🕷️ Crawler Inspector

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1. Shard Calculation

Query:

Response:

Calculated Shard: 152 (from laksa133)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa152.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, attrs_boilerpipe_text AS attrs_boilerpipe_text, attrs_markdown AS attrs_markdown, attrs_readable_markdown AS attrs_readable_markdown, meta_canonical AS meta_canonical, ml_categories_json AS ml_categories_json, ml_types_json AS ml_types_json, ml_intent_types_json AS ml_intent_types_json, meta_language AS meta_language, attrs_author AS attrs_author, ifNull(toUnixTimestamp(attrs_publish_time), 0) AS attrs_publish_time, ifNull(toUnixTimestamp(attrs_original_publish_time), 0) AS attrs_original_publish_time, ifNull(attrs_is_republished, 0) AS attrs_is_republished, ifNull(attrs_nr_words, 0) AS attrs_nr_words, ifNull(attrs_boilerpipe_nr_words, 0) AS attrs_boilerpipe_nr_words, ifNull(body_ext_links_number, 0) AS body_ext_links_number, ifNull(body_int_links_number, 0) AS body_int_links_number, ifNull(meta_nofollow, 0) AS meta_nofollow, ifNull(meta_noarchive, 0) AS meta_noarchive, ifNull(props_was_rendered, 0) AS props_was_rendered, ifNull(src_redirect, \'\') AS src_redirect, ifNull(download_time_msec, 0) AS download_time_msec, ifNull(download_ttfb_msec, 0) AS download_ttfb_msec, ifNull(download_size, 0) AS download_size FROM crawler3.page_info_local FINAL PREWHERE (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://en.wikipedia.org/wiki/Fuel_efficiency\')), getAhrefsUnparsedNoserviceFromURL(\'https://en.wikipedia.org/wiki/Fuel_efficiency\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency","crawl_time":1775977587,"first_indexed_time":1375989515,"http_code":200,"src_unparsed":"org,wikipedia!en,\/wiki\/Fuel_efficiency s443","src_root_hash":"17790707453426894952","history_drop_reason":null,"meta_title":"Fuel efficiency - Wikipedia","meta_descriptions":[],"attrs_boilerpipe_text":"From Wikipedia, the free encyclopedia\nFuel efficiency\n(or\nfuel economy\n) is a form of\nthermal efficiency\n, meaning the\nratio\nof effort to result of a process that converts\nchemical\npotential energy\ncontained in a carrier (\nfuel\n) into kinetic energy or\nwork\n. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous\nenergy profile\n. Non-transportation applications, such as\nindustry\n, benefit from increased fuel efficiency, especially\nfossil fuel power plants\nor industries dealing with\ncombustion\n, such as\nammonia\nproduction during the\nHaber process\n.\nIn the context of\ntransport\n, fuel economy is the\nenergy efficiency\nof a particular vehicle,  given as a\nratio\nof distance traveled per unit of\nfuel\nconsumed. It is dependent on several factors  including\nengine efficiency\n,\ntransmission\ndesign, and\ntire\ndesign. In most countries, using the\nmetric system\n, fuel economy is stated as \"fuel consumption\" in\nliters\nper 100\nkilometers\n(L\/100 km) or kilometers per liter (km\/L or kmpl). In a number of countries still using other systems, fuel economy is expressed in\nmiles\nper\ngallon\n(mpg), for example in the US and usually also in the UK (\nimperial\ngallon); there is sometimes confusion as the imperial gallon is 20% larger than the US gallon so that mpg values are not directly comparable.  Traditionally, litres per\nmil\nwere used in\nNorway\nand\nSweden\n, but both have aligned to the EU standard of L\/100 km.\n[\n1\n]\nFuel consumption is a more accurate measure of a vehicle's performance because it is a linear relationship while fuel economy leads to distortions in efficiency improvements.\n[\n2\n]\nWeight-specific efficiency (efficiency per unit weight) may be stated for\nfreight\n, and passenger-specific efficiency (vehicle efficiency per passenger) for passenger vehicles.\nFuel efficiency is dependent on many parameters of a vehicle, including its\nengine\nparameters,\naerodynamic drag\n, weight, AC usage, fuel and\nrolling resistance\n. There have been advances in all areas of vehicle design in recent decades. Fuel efficiency of vehicles can also be improved by careful maintenance and driving habits.\n[\n3\n]\nHybrid vehicles\nuse two or more power sources for propulsion. In many designs, a small combustion engine is combined with electric motors.  Kinetic energy which would otherwise be lost to heat during braking is recaptured as electrical power to improve fuel efficiency. The larger batteries in these vehicles power the\ncar's electronics\n, allowing the engine to shut off and avoid prolonged\nidling\n.\n[\n4\n]\nTrucks' share of US vehicles produced, has tripled since 1975. Though vehicle fuel efficiency has increased within each category, the overall trend toward less efficient types of vehicles has offset some of the benefits of greater fuel economy and reduction in carbon dioxide emissions.\n[\n5\n]\nWithout the shift towards SUVs, energy use per unit distance could have fallen 30% more than it did from 2010 to 2022.\n[\n6\n]\nFleet efficiency describes the average efficiency of a population of vehicles.  Technological advances in efficiency may be offset by a change in buying habits with a propensity to heavier vehicles that are less fuel-efficient.\n[\n5\n]\nEnergy efficiency terminology\n[\nedit\n]\nEnergy efficiency\nis similar to fuel efficiency but the input is usually in units of energy such as\nmegajoules\n(MJ),\nkilowatt-hours\n(kW·h), kilocalories (kcal) or\nBritish thermal units\n(BTU). The inverse of \"energy efficiency\" is \"\nenergy intensity\n\", or the amount of input energy required for a unit of output such as MJ\/passenger-km (of passenger transport), BTU\/ton-mile or kJ\/t-km (of freight transport), GJ\/t (for production of steel and other materials), BTU\/(kW·h) (for electricity generation), or litres\/100 km (of vehicle travel). Litres per 100 km is also a measure of \"energy intensity\" where the input is measured by the amount of fuel and the output is measured by the\ndistance\ntravelled.  For example:\nFuel economy in automobiles\n.\nGiven a heat value of a fuel, it would be trivial to convert from fuel units (such as litres of gasoline) to energy units (such as MJ) and conversely. But there are two problems with comparisons made using energy units:\nThere are two different heat values for any hydrogen-containing fuel which can differ by several percent (see below).\nWhen comparing transportation energy costs, a\nkilowatt hour\nof electric energy may require an amount of fuel with heating value of 2 or 3 kilowatt hours to produce it.\nEnergy content of fuel\n[\nedit\n]\nThe specific\nenergy content\nof a fuel is the heat energy obtained when a certain quantity is burned (such as a gallon, litre, kilogram).  It is sometimes called the\nheat of combustion\n.  There exists two different values of\nspecific heat\nenergy for the same batch of fuel.  One is the high (or gross) heat of combustion and the other is the low (or net) heat of combustion.  The high value is obtained when, after the combustion, the water in the exhaust is in liquid form.  For the low value, the exhaust has all the water in vapor form (steam).  Since water vapor gives up heat energy when it changes from vapor to liquid, the liquid water value is larger since it includes the\nlatent heat\nof vaporization of water.  The difference between the high and low values is significant, about 8 or 9%.  This accounts for most of the apparent discrepancy in the heat value of gasoline. In the U.S. (and the table) the high heat values have traditionally been used, but in many other countries, the low heat values are commonly used.\nFuel type\nMJ\/L\nMJ\/kg\nBTU\n\/\nimp gal\nBTU\/\nUS gal\nResearch octane\nnumber (RON)\nRegular\ngasoline\n\/petrol\n34.8\n~47\n150,100\n125,000\nMin. 91\nPremium\ngasoline\n\/petrol\n~46\nMin. 95\nAutogas\n(\nLPG\n) (60%\npropane\nand 40%\nbutane\n)\n25.5–28.7\n~51\n108–110\nEthanol\n23.5\n31.1\n[\n7\n]\n101,600\n84,600\n129\nMethanol\n17.9\n19.9\n77,600\n64,600\n123\nGasohol\n(10% ethanol and 90% gasoline)\n33.7\n~45\n145,200\n121,000\n93\/94\nE85\n(85% ethanol and 15% gasoline)\n25.2\n~33\n108,878\n90,660\n100–105\nDiesel\n38.6\n~48\n166,600\n138,700\nN\/A (see cetane)\nBiodiesel\n35.1\n39.9\n151,600\n126,200\nN\/A (see cetane)\nVegetable oil\n(using 9.00 kcal\/g)\n34.3\n37.7\n147,894\n123,143\nAviation gasoline\n33.5\n46.8\n144,400\n120,200\n80-145\nJet fuel\n, naphtha\n35.5\n46.6\n153,100\n127,500\nN\/A to turbine engines\nJet fuel\n, kerosene\n37.6\n~47\n162,100\n135,000\nN\/A to turbine engines\nLiquefied natural gas\n25.3\n~55\n109,000\n90,800\nLiquid hydrogen\n9.3\n~130\n40,467\n33,696\n[\n8\n]\nNeither the gross heat of combustion nor the net heat of combustion gives the theoretical amount of mechanical energy (work) that can be obtained from the reaction. (This is given by the change in\nGibbs free energy\n, and is around 45.7 MJ\/kg for gasoline.) The actual amount of mechanical work obtained from fuel (the inverse of the\nspecific fuel consumption\n) depends on the engine. A figure of 17.6 MJ\/kg is possible with a gasoline engine, and 19.1 MJ\/kg for a diesel engine. See\nBrake-specific fuel consumption\nfor more information.\n[\nclarification needed\n]\nThe\nenergy efficiency in transport\nis the useful travelled\ndistance\n, of passengers, goods or any type of load; divided by the total\nenergy\nput into the transport\npropulsion\nmeans. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in\nliquid fuels\n,\nelectrical energy\nor\nfood energy\n.\n[\n9\n]\n[\n10\n]\nThe\nenergy efficiency\nis also occasionally known as\nenergy intensity\n.\n[\n11\n]\nThe\ninverse\nof the energy efficiency in transport is the energy consumption in transport.\nEnergy efficiency in transport is often described in terms of\nfuel consumption\n, fuel consumption being the reciprocal of fuel economy.\n[\n10\n]\nNonetheless, fuel consumption is linked with a means of propulsion which uses\nliquid fuels\n, whilst energy efficiency is applicable to any sort of propulsion. To avoid said confusion, and to be able to compare the energy efficiency in any type of vehicle, experts tend to measure the energy in the\nInternational System of Units\n, i.e.,\njoules\n.\nTherefore, in the International System of Units, the energy efficiency in transport is measured in terms of metre per joule, or m\/J, while the energy consumption in transport is measured in terms of joules per metre, or J\/m. The more efficient the vehicle, the more metres it covers with one joule (more efficiency), or the fewer joules it uses to travel over one metre (less consumption). The\nenergy efficiency\nin transport largely varies by means of transport. Different types of\ntransport\nrange from some hundred\nkilojoules\nper kilometre (kJ\/km) for a\nbicycle\nto tens of megajoules per kilometre (MJ\/km) for a\nhelicopter\n.\nVia type of fuel used and rate of fuel consumption, energy efficiency is also often related to operating cost ($\/km) and environmental emissions (e.g. CO\n2\n\/km).\nFuel efficiency of motor vehicles\n[\nedit\n]\nNew light-duty vehicle fuel economy by vehicle type from vehicle manufacturers in the United States, in miles per gallon (1975 - 2019)\nFuel consumption monitor from a 2006\nHonda Airwave\n. The displayed fuel economy is 18.1 km\/L (5.5 L\/100 km; 43 mpg\n‑US\n).\nA\nBriggs and Stratton Flyer\nfrom 1916. Originally an experiment in creating a fuel-saving automobile in the United States, the vehicle weighed only 135 lb (61.2 kg) and was an adaptation of a small gasoline engine originally designed to power a bicycle.\n[\n12\n]\nThe\nfuel economy\nor fuel efficiency of an\nautomobile\nrelates to the\ndistance traveled\nby a vehicle and the amount of\nfuel\nconsumed. It can be expressed in terms of the volume of fuel to travel a given distance, such as in litres per 100 kilometres (L\/100\n \nkm), or through its inverse, the distance traveled per unit volume of fuel consumed, as in kilometres per litre (km\/L) or miles per gallon (mpg). Since fuel economy of vehicles is a significant factor in\nair pollution\n, the importation of\nmotor fuel\ncan be a large part of a nation's\nforeign trade\nand consumers frequently undervalue fuel efficiency, many countries impose requirements for fuel economy.\nDifferent methods are used to approximate the actual performance of the vehicle. The energy in fuel is required to overcome various losses (\nwind resistance\n,\ntire drag\n, and others) encountered while propelling the vehicle, and in providing power to vehicle systems such as ignition or air conditioning. Various strategies can be employed to reduce losses at each of the conversions between the\nchemical energy\nin the fuel and the\nkinetic energy\nof the vehicle. Driver behavior can affect fuel economy; maneuvers such as sudden acceleration and heavy\nbraking\nwaste energy.\nElectric cars\nuse\nkilowatt-hours\nof electricity per 100 kilometres (kWh\/100km); in the U.S., an equivalence measure, such as\nmiles per gallon gasoline equivalent\n(US gallon) has been created to attempt to compare them.\nEnergy-efficient driving\ntechniques are used by drivers who wish to reduce their fuel consumption, and thus maximize fuel efficiency. Many drivers have the potential to improve their fuel efficiency significantly.\n[\n13\n]\nSimple things such as keeping tires properly inflated, having a vehicle well-maintained and avoiding idling can dramatically improve fuel efficiency.\n[\n14\n]\nCareful use of acceleration and deceleration and especially limiting use of high speeds helps efficiency. The use of multiple such techniques is called \"\nhypermiling\n\".\n[\n15\n]\nWhile these techniques can be applied by any driver, energy-efficient driving (often called \"eco-driving\") has become a major focus of modern\nfleet management\n. As a key part of\nfleet digitalization\n, companies use\ntelematics\nto automatically monitor and manage fuel economy. A\nfleet telematics system\ncollects data on behaviors that waste fuel, such as harsh acceleration, speeding, and idling. This information is then used in\ndriver scoring\napplications to identify and coach drivers.\n[\n13\n]\nThis is often combined with dedicated\nfuel-management systems\nthat use high-precision\nfuel level sensors\nto get exact fuel consumption data and prevent\ngasoline theft\n.\n[\n16\n]\nSimple fuel-efficiency techniques can result in reduction in fuel consumption without resorting to radical fuel-saving techniques that can be unlawful and dangerous, such as tailgating larger vehicles.\nAdvanced technology\n[\nedit\n]\nThe most efficient machines for converting energy to rotary motion are electric motors, as used in\nelectric vehicles\n. However, electricity is not a primary energy source so the efficiency of the electricity production has also to be taken into account.\nRailway\ntrains can be powered using electricity, delivered through an additional running rail, overhead\ncatenary\nsystem or by on-board generators used in\ndiesel-electric\nlocomotives as common on the US and UK rail networks. Pollution produced from centralised generation of electricity is emitted at a distant power station, rather than \"on site\". Pollution can be reduced by using more railway electrification and\nlow carbon power\nfor electricity. Some railways, such as the French SNCF and Swiss federal railways derive most, if not 100% of their power, from hydroelectric or nuclear power stations, therefore atmospheric pollution from their rail networks is very low. This was reflected in a study by AEA Technology between a\nEurostar\ntrain and airline journeys between London and Paris, which showed the trains on average emitting 10 times less CO\n2\n, per passenger, than planes, helped in part by French nuclear generation.\n[\n17\n]\nHydrogen fuel cells\n[\nedit\n]\nIn the future,\nhydrogen cars\nmay be commercially available. Toyota is test-marketing vehicles powered by hydrogen fuel cells in southern California, where a series of hydrogen fueling stations has been established. Powered either through chemical reactions in a\nfuel cell\nthat create electricity to drive very efficient electrical motors or by directly burning hydrogen in a combustion engine (near identically to a\nnatural gas vehicle\n, and similarly compatible with both natural gas and gasoline); these vehicles promise to have near-zero pollution from the tailpipe (exhaust pipe). Potentially the atmospheric pollution could be minimal, provided the hydrogen is made by\nelectrolysis\nusing electricity from non-polluting sources such as solar, wind or\nhydroelectricity\nor nuclear. Commercial\nhydrogen production\nuses fossil fuels and produces more carbon dioxide than hydrogen.\nBecause there are pollutants involved in the manufacture and destruction of a car and the production, transmission and storage of electricity and hydrogen, the label \"zero pollution\" applies only to the car's conversion of stored energy into movement.\nIn 2004, a consortium of major auto-makers —\nBMW\n,\nGeneral Motors\n,\nHonda\n,\nToyota\nand\nVolkswagen\n\/\nAudi\n— came up with\n\"Top Tier Detergent Gasoline Standard\"\nto\ngasoline\nbrands in the US and Canada that meet their minimum standards for\ndetergent\ncontent\n[\n18\n]\nand do not contain metallic additives. Top Tier gasoline contains higher levels of detergent additives in order to prevent the build-up of deposits (typically, on\nfuel injector\nand\nintake valve\n) known to reduce fuel economy and engine performance.\n[\n19\n]\nHow fuel combusts affects how much energy is produced. The\nNational Aeronautics and Space Administration\n(NASA) has investigated fuel consumption in\nmicrogravity\n.\nThe common distribution of a flame under normal gravity conditions depends on\nconvection\n, because soot tends to rise to the top of a flame, such as in a candle, making the flame yellow. In microgravity or\nzero gravity\n, such as an environment in\nouter space\n, convection no longer occurs, and the flame becomes\nspherical\n, with a tendency to become more blue and more efficient. There are several possible explanations for this difference, of which the most likely one given is the hypothesis that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs., National Aeronautics and Space Administration, April 2005. Experiments by NASA in microgravity reveal that\ndiffusion flames\nin microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions.\nLSP-1 experiment results\n, National Aeronautics and Space Administration, April 2005.\nPremixed flames\nin microgravity burn at a much slower rate and more efficiently than even a candle on Earth, and last much longer.\n[\n20\n]\nAnnual fuel utilization efficiency\n(AFUE)\nACEA agreement\nAlternative propulsion\nCamless piston engine\nCarbon dioxide equivalent\nCorporate Average Fuel Economy\n(CAFE)\nEcoAuto\n(in Canada)\nEfficient energy use\nEmission standard\nEnergy content of Biofuel\nEnergy conservation\nEnergy conversion efficiency\nEnergy density\nFF layout\nFront-wheel drive\nFuel economy in aircraft\nFuel economy in automobiles\nFuel economy maximising behaviors\nFuel efficiency in transportation\nGas-guzzler\nHeating value\nJevons paradox\nLife cycle assessment\nLow-rolling resistance tires\nMiles per gallon gasoline equivalent\nMarine fuel management\nTwinjet\nVariable valve timing\nUnibody\nAutomobile costs\nVehicle metrics\n^\n\"Information on the fuel consumption of new cars\"\n. Archived from\nthe original\non 8 September 2019\n. Retrieved\n7 November\n2019\n.\n^\n\"Learn More About the Fuel Economy Label for Gasoline Vehicles\"\n.\nArchived\nfrom the original on 2013-07-05.\n^\n\"Simple tips and tricks to increase fuel efficiency of your car | CarSangrah\"\n.\nCarSangrah\n. 2018-06-07\n. Retrieved\n2018-07-24\n.\n^\n\"How Hybrids Work\"\n.\nU.S. Department of Energy\n.\nArchived\nfrom the original on 2015-07-08\n. Retrieved\n2014-01-16\n.\n^\na\nb\n\"Highlights of the Automotive Trends Report\"\n.\nEPA.gov\n. U.S. Environmental Protection Agency (EPA). 12 December 2022.\nArchived\nfrom the original on 2 September 2023.\n^\nCazzola, Pierpaolo; Paoli, Leonardo; Teter, Jacob (November 2023).\n\"Trends in the Global Vehicle Fleet 2023 \/ Managing the SUV Shift and the EV Transition\"\n(PDF)\n. Global Fuel Economy Initiative (GFEI). p. 3.\ndoi\n:\n10.7922\/G2HM56SV\n.\nArchived\n(PDF)\nfrom the original on 26 November 2023.\n^\nCalculated from heats of formation. Does not correspond exactly to the figure for MJ\/L divided by density.\n^\nAppendix B, Transportation Energy Data Book\nfrom the\nCenter for Transportation Analysis\nof the\nOak Ridge National Laboratory\n^\n\"Efficiency\"\n. Retrieved\n18 September\n2016\n.\n^\na\nb\nAssessment of Fuel Economy Technologies for Light-duty Vehicles\n. The National Academies Press. 2011.\ndoi\n:\n10.17226\/12924\n.\nISBN\n \n978-0-309-15607-3\n. Retrieved\n18 September\n2016\n.\n^\n\"Glossary of energy-related terms\"\n.\nU.S. Department of Energy\n. Retrieved\n20 September\n2016\n.\n^\nPage, Walter Hines; Page, Arthur Wilson (1916).\n\"Man and His Machines\"\n.\nThe World's Work\n. Vol. XXXIII. Garden City, New York: Doubleday, Page & Co.\n^\na\nb\nBeusen; et al. (2009).\n\"Using on-board logging devices to study the long-term impact of an eco-driving course\"\n.\nTransportation Research D\n.\n14\n(7):\n514–\n520.\nBibcode\n:\n2009TRPD...14..514B\n.\ndoi\n:\n10.1016\/j.trd.2009.05.009\n.\nArchived\nfrom the original on 2013-10-19.\n^\n\"20 Ways to Improve Your Fuel Efficiency and Save Money at the Pump\"\n.\nArchived\nfrom the original on 2016-08-16.\n^\nhttp:\/\/www.merriam-webster.com\/dictionary\/hypermiling\nMerriam Webster dictionary\n^\n\"Staying Ahead Of The Curve: 3 Key Fleet Management Trends For 2023\"\n.\nForbes\n. April 18, 2023\n. Retrieved\nOctober 7,\n2025\n.\n^\n\"Rail 10 times better than air in London-Paris CO2 comparison - Transport & Environment\"\n.\nArchived\nfrom the original on 2007-09-28.\n^\nTop Tier Gasoline\nArchived\n2013-08-15 at the\nWayback Machine\n^\n\"Deposit Control Standards\"\n. Archived from\nthe original\non 2004-08-06\n. Retrieved\n2012-10-19\n.\n^\nSOFBAL-2 experiment results\nArchived\n2007-03-12 at the\nWayback Machine\n, National Aeronautics and Space Administration, April 2005.\nUS Government website on fuel economy\nUK DfT comparisons on road and rail\nNASA Offers a $1.5 Million Prize for a Fast and Fuel-Efficient Aircraft\nArchived\n2016-03-03 at the\nWayback Machine\nCar Fuel Consumption Official Figures\nSpritmonitor.de \"the most fuel efficient cars\" - Database of thousands of (mostly German) car owners' actual fuel consumption figures\n(cf.\nSpritmonitor\n)\nSearchable fuel economy data from the EPA - United States Environmental Protection Agency\npenghemat bbm - Alat penghemat bbm\nNy Times: A Road Test of Alternative Fuel Visions","attrs_markdown":"[Jump to content](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#bodyContent)\n\nMain menu\n\nMain menu\n\nmove to sidebar\n\nhide\n\nNavigation\n\n- [Main page](https:\/\/en.wikipedia.org\/wiki\/Main_Page \"Visit the main page [z]\")\n- [Contents](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Contents \"Guides to browsing Wikipedia\")\n- [Current events](https:\/\/en.wikipedia.org\/wiki\/Portal:Current_events \"Articles related to current events\")\n- [Random article](https:\/\/en.wikipedia.org\/wiki\/Special:Random \"Visit a randomly selected article [x]\")\n- [About Wikipedia](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:About \"Learn about Wikipedia and how it works\")\n- [Contact us](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Contact_us \"How to contact Wikipedia\")\n\nContribute\n\n- [Help](https:\/\/en.wikipedia.org\/wiki\/Help:Contents \"Guidance on how to use and edit Wikipedia\")\n- [Learn to edit](https:\/\/en.wikipedia.org\/wiki\/Help:Introduction \"Learn how to edit Wikipedia\")\n- [Community portal](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Community_portal \"The hub for editors\")\n- [Recent changes](https:\/\/en.wikipedia.org\/wiki\/Special:RecentChanges \"A list of recent changes to Wikipedia [r]\")\n- [Upload file](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:File_upload_wizard \"Add images or other media for use on Wikipedia\")\n- [Special pages](https:\/\/en.wikipedia.org\/wiki\/Special:SpecialPages \"A list of all special pages [q]\")\n\n[![](https:\/\/en.wikipedia.org\/static\/images\/icons\/enwiki-25.svg) ![Wikipedia](https:\/\/en.wikipedia.org\/static\/images\/mobile\/copyright\/wikipedia-wordmark-en-25.svg) ![The Free Encyclopedia](https:\/\/en.wikipedia.org\/static\/images\/mobile\/copyright\/wikipedia-tagline-en-25.svg)](https:\/\/en.wikipedia.org\/wiki\/Main_Page)\n\n[Search](https:\/\/en.wikipedia.org\/wiki\/Special:Search \"Search Wikipedia [f]\")\n\nAppearance\n\n- [Donate](https:\/\/donate.wikimedia.org\/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en)\n- [Create account](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CreateAccount&returnto=Fuel+efficiency \"You are encouraged to create an account and log in; however, it is not mandatory\")\n- [Log in](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:UserLogin&returnto=Fuel+efficiency \"You're encouraged to log in; however, it's not mandatory. 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[o]\")\n\n## Contents\nmove to sidebar\n\nhide\n\n- [(Top)](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency)\n- [1 Vehicle design](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#Vehicle_design)\n- [2 Fleet efficiency](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#Fleet_efficiency)\n- [3 Energy efficiency terminology](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#Energy_efficiency_terminology)\n- [4 Energy content of fuel](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#Energy_content_of_fuel)\n- [5 Transportation](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#Transportation)\n  Toggle Transportation subsection\n  - [5\\.1 Fuel efficiency of motor vehicles](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#Fuel_efficiency_of_motor_vehicles)\n  - [5\\.2 Driving technique](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#Driving_technique)\n- [6 Advanced technology](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#Advanced_technology)\n  Toggle Advanced technology subsection\n  - [6\\.1 Hydrogen fuel cells](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#Hydrogen_fuel_cells)\n  - [6\\.2 In microgravity](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#In_microgravity)\n- [7 See also](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#See_also)\n- [8 References](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#References)\n- [9 External links](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#External_links)\n\nToggle the table of contents\n\n# Fuel efficiency\n8 languages\n\n- [العربية](https:\/\/ar.wikipedia.org\/wiki\/%D9%83%D9%81%D8%A7%D8%A1%D8%A9_%D8%A7%D9%84%D9%88%D9%82%D9%88%D8%AF \"كفاءة الوقود – Arabic\")\n- [Català](https:\/\/ca.wikipedia.org\/wiki\/Efici%C3%A8ncia_de_combustible \"Eficiència de combustible – Catalan\")\n- [فارسی](https:\/\/fa.wikipedia.org\/wiki\/%D8%A8%D8%A7%D8%B2%D8%AF%D9%87%DB%8C_%D8%B3%D9%88%D8%AE%D8%AA \"بازدهی سوخت – Persian\")\n- [Bahasa Indonesia](https:\/\/id.wikipedia.org\/wiki\/Efisiensi_bahan_bakar \"Efisiensi bahan bakar – Indonesian\")\n- [Bahasa Melayu](https:\/\/ms.wikipedia.org\/wiki\/Kecekapan_bahan_api \"Kecekapan bahan api – Malay\")\n- [Türkçe](https:\/\/tr.wikipedia.org\/wiki\/Yak%C4%B1t_verimlili%C4%9Fi \"Yakıt verimliliği – Turkish\")\n- [Українська](https:\/\/uk.wikipedia.org\/wiki\/%D0%95%D1%84%D0%B5%D0%BA%D1%82%D0%B8%D0%B2%D0%BD%D1%96%D1%81%D1%82%D1%8C_%D0%BF%D0%B0%D0%BB%D0%B8%D0%B2%D0%B0 \"Ефективність палива – Ukrainian\")\n- [中文](https:\/\/zh.wikipedia.org\/wiki\/%E7%87%83%E6%B2%B9%E6%95%88%E7%8E%87 \"燃油效率 – Chinese\")\n\n[Edit links](https:\/\/www.wikidata.org\/wiki\/Special:EntityPage\/Q5042317#sitelinks-wikipedia \"Edit interlanguage links\")\n\n- [Article](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency \"View the content page [c]\")\n- [Talk](https:\/\/en.wikipedia.org\/wiki\/Talk:Fuel_efficiency \"Discuss improvements to the content page [t]\")\n\nEnglish\n\n- [Read](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency)\n- [Edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit \"Edit this page [e]\")\n- [View history](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=history \"Past revisions of this page [h]\")\n\nTools\n\nTools\n\nmove to sidebar\n\nhide\n\nActions\n\n- [Read](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency)\n- [Edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit \"Edit this page [e]\")\n- [View history](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=history)\n\nGeneral\n\n- [What links here](https:\/\/en.wikipedia.org\/wiki\/Special:WhatLinksHere\/Fuel_efficiency \"List of all English Wikipedia pages containing links to this page [j]\")\n- [Related changes](https:\/\/en.wikipedia.org\/wiki\/Special:RecentChangesLinked\/Fuel_efficiency \"Recent changes in pages linked from this page [k]\")\n- [Upload file](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:File_Upload_Wizard \"Upload files [u]\")\n- [Permanent link](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&oldid=1317110748 \"Permanent link to this revision of this page\")\n- [Page information](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=info \"More information about this page\")\n- [Cite this page](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CiteThisPage&page=Fuel_efficiency&id=1317110748&wpFormIdentifier=titleform \"Information on how to cite this page\")\n- [Get shortened URL](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FFuel_efficiency)\n\nPrint\/export\n\n- [Download as PDF](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:DownloadAsPdf&page=Fuel_efficiency&action=show-download-screen \"Download this page as a PDF file\")\n- [Printable version](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&printable=yes \"Printable version of this page [p]\")\n\nIn other projects\n\n- [Wikidata item](https:\/\/www.wikidata.org\/wiki\/Special:EntityPage\/Q5042317 \"Structured data on this page hosted by Wikidata [g]\")\n\nAppearance\n\nmove to sidebar\n\nhide\n\nFrom Wikipedia, the free encyclopedia\n\nForm of thermal efficiency\n\n| [Infrastructure](https:\/\/en.wikipedia.org\/wiki\/Infrastructure \"Infrastructure\") |\n|---|\n| [![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/d\/d8\/Grand_Coulee_Dam_spillway.jpg\/250px-Grand_Coulee_Dam_spillway.jpg)](https:\/\/en.wikipedia.org\/wiki\/File:Grand_Coulee_Dam_spillway.jpg)[Grand Coulee Dam](https:\/\/en.wikipedia.org\/wiki\/Grand_Coulee_Dam \"Grand Coulee Dam\") |\n| [Assets](https:\/\/en.wikipedia.org\/wiki\/Fixed_asset \"Fixed asset\") and facilities [Airports](https:\/\/en.wikipedia.org\/wiki\/Airport \"Airport\") [Bridges](https:\/\/en.wikipedia.org\/wiki\/Bridge \"Bridge\") [Broadband](https:\/\/en.wikipedia.org\/wiki\/Broadband \"Broadband\") [Canals](https:\/\/en.wikipedia.org\/wiki\/Canal \"Canal\") [Coastal management](https:\/\/en.wikipedia.org\/wiki\/Coastal_management \"Coastal management\") [Critical infrastructure](https:\/\/en.wikipedia.org\/wiki\/Critical_infrastructure \"Critical infrastructure\") [Dams](https:\/\/en.wikipedia.org\/wiki\/Dam \"Dam\") [Electricity](https:\/\/en.wikipedia.org\/wiki\/Electricity_generation \"Electricity generation\") [Energy](https:\/\/en.wikipedia.org\/wiki\/Energy_development \"Energy development\") [Hazardous waste](https:\/\/en.wikipedia.org\/wiki\/Hazardous_waste \"Hazardous waste\") [Hospitals](https:\/\/en.wikipedia.org\/wiki\/Hospital \"Hospital\") [Irrigation](https:\/\/en.wikipedia.org\/wiki\/Irrigation \"Irrigation\") [Levees](https:\/\/en.wikipedia.org\/wiki\/Levee \"Levee\") [Lighthouses](https:\/\/en.wikipedia.org\/wiki\/Lighthouse \"Lighthouse\") [Parks](https:\/\/en.wikipedia.org\/wiki\/Park \"Park\") [Pipeline](https:\/\/en.wikipedia.org\/wiki\/Pipeline \"Pipeline\") [Ports](https:\/\/en.wikipedia.org\/wiki\/Port \"Port\") [Mass transit](https:\/\/en.wikipedia.org\/wiki\/Public_transport \"Public transport\") [Public housing](https:\/\/en.wikipedia.org\/wiki\/Public_housing \"Public housing\") [State schools](https:\/\/en.wikipedia.org\/wiki\/State_school \"State school\") [Public spaces](https:\/\/en.wikipedia.org\/wiki\/Public_space \"Public space\") [Rail](https:\/\/en.wikipedia.org\/wiki\/Rail_transport \"Rail transport\") [Roads](https:\/\/en.wikipedia.org\/wiki\/Road \"Road\") [Sewage treatment](https:\/\/en.wikipedia.org\/wiki\/Sewage_treatment \"Sewage treatment\") [Sewerage](https:\/\/en.wikipedia.org\/wiki\/Sewerage \"Sewerage\") [Sluices](https:\/\/en.wikipedia.org\/wiki\/Sluice \"Sluice\") [Snow removal](https:\/\/en.wikipedia.org\/wiki\/Snow_removal \"Snow removal\") [Solid waste](https:\/\/en.wikipedia.org\/wiki\/Municipal_solid_waste \"Municipal solid waste\") [Telecommunications](https:\/\/en.wikipedia.org\/wiki\/Telecommunications \"Telecommunications\") [Trails](https:\/\/en.wikipedia.org\/wiki\/Trail \"Trail\") [Utilities](https:\/\/en.wikipedia.org\/wiki\/Public_utility \"Public utility\") [Water supply](https:\/\/en.wikipedia.org\/wiki\/Water_supply_network \"Water supply network\") [Weirs](https:\/\/en.wikipedia.org\/wiki\/Weir \"Weir\") |\n| Concepts [Asset management](https:\/\/en.wikipedia.org\/wiki\/Infrastructure_asset_management \"Infrastructure asset management\") [Appropriation](https:\/\/en.wikipedia.org\/wiki\/Appropriation_\$law\$ \"Appropriation (law)\") [Lindahl tax](https:\/\/en.wikipedia.org\/wiki\/Lindahl_tax \"Lindahl tax\") [Build–operate–transfer](https:\/\/en.wikipedia.org\/wiki\/Build%E2%80%93operate%E2%80%93transfer \"Build–operate–transfer\") [Design–bid–build](https:\/\/en.wikipedia.org\/wiki\/Design%E2%80%93bid%E2%80%93build \"Design–bid–build\") [Design–build](https:\/\/en.wikipedia.org\/wiki\/Design%E2%80%93build \"Design–build\") [Earmark](https:\/\/en.wikipedia.org\/wiki\/Earmark_\$politics\$ \"Earmark (politics)\") [European green infrastructure](https:\/\/en.wikipedia.org\/wiki\/European_green_infrastructure \"European green infrastructure\") [Fixed cost](https:\/\/en.wikipedia.org\/wiki\/Fixed_cost \"Fixed cost\") [Engineering contracts](https:\/\/en.wikipedia.org\/wiki\/Infrastructure#Engineering \"Infrastructure\") [Externality](https:\/\/en.wikipedia.org\/wiki\/Externality \"Externality\") [Government debt](https:\/\/en.wikipedia.org\/wiki\/Government_debt \"Government debt\") [Green infrastructure](https:\/\/en.wikipedia.org\/wiki\/Green_infrastructure \"Green infrastructure\") [Life-cycle assessment](https:\/\/en.wikipedia.org\/wiki\/Life-cycle_assessment \"Life-cycle assessment\") [Maintenance](https:\/\/en.wikipedia.org\/wiki\/Maintenance \"Maintenance\") [Monopoly](https:\/\/en.wikipedia.org\/wiki\/Natural_monopoly \"Natural monopoly\") [Property tax](https:\/\/en.wikipedia.org\/wiki\/Property_tax \"Property tax\") [Public–private partnership](https:\/\/en.wikipedia.org\/wiki\/Public%E2%80%93private_partnership \"Public–private partnership\") [Public capital](https:\/\/en.wikipedia.org\/wiki\/Public_capital \"Public capital\") [Public finance](https:\/\/en.wikipedia.org\/wiki\/Public_finance \"Public finance\") [Public good](https:\/\/en.wikipedia.org\/wiki\/Public_good \"Public good\") [Public sector](https:\/\/en.wikipedia.org\/wiki\/Public_sector \"Public sector\") [Renovation](https:\/\/en.wikipedia.org\/wiki\/Renovation \"Renovation\") [Replacement (upgrade)](https:\/\/en.wikipedia.org\/wiki\/Upgrade \"Upgrade\") [Spillover](https:\/\/en.wikipedia.org\/wiki\/Spillover_\$economics\$ \"Spillover (economics)\") [Supply chain](https:\/\/en.wikipedia.org\/wiki\/Supply_chain \"Supply chain\") [Tax](https:\/\/en.wikipedia.org\/wiki\/Tax \"Tax\") |\n| Issues and ideas [Air traffic control](https:\/\/en.wikipedia.org\/wiki\/Air_traffic_control \"Air traffic control\") [Brownfield](https:\/\/en.wikipedia.org\/wiki\/Brownfield_land \"Brownfield land\") [Carbon footprint](https:\/\/en.wikipedia.org\/wiki\/Carbon_footprint \"Carbon footprint\") [Containerization](https:\/\/en.wikipedia.org\/wiki\/Containerization \"Containerization\") [Congestion pricing](https:\/\/en.wikipedia.org\/wiki\/Congestion_pricing \"Congestion pricing\") [Environmental tax](https:\/\/en.wikipedia.org\/wiki\/Environmental_tax \"Environmental tax\") [Ethanol fuel](https:\/\/en.wikipedia.org\/wiki\/Ethanol_fuel \"Ethanol fuel\") [Fuel tax](https:\/\/en.wikipedia.org\/wiki\/Fuel_tax \"Fuel tax\") [Groundwater](https:\/\/en.wikipedia.org\/wiki\/Groundwater \"Groundwater\") [High-speed rail](https:\/\/en.wikipedia.org\/wiki\/High-speed_rail \"High-speed rail\") [Hybrid vehicles](https:\/\/en.wikipedia.org\/wiki\/Hybrid_vehicle \"Hybrid vehicle\") [Land-use planning](https:\/\/en.wikipedia.org\/wiki\/Land-use_planning \"Land-use planning\") [Mobile data terminal](https:\/\/en.wikipedia.org\/wiki\/Mobile_data_terminal \"Mobile data terminal\") [Pork barrel](https:\/\/en.wikipedia.org\/wiki\/Pork_barrel \"Pork barrel\") [Rapid bus transit](https:\/\/en.wikipedia.org\/wiki\/Bus_rapid_transit \"Bus rapid transit\") [Recycling](https:\/\/en.wikipedia.org\/wiki\/Recycling \"Recycling\") [Renewables](https:\/\/en.wikipedia.org\/wiki\/Renewable_resource \"Renewable resource\") [Reverse osmosis](https:\/\/en.wikipedia.org\/wiki\/Reverse_osmosis \"Reverse osmosis\") [Smart grid](https:\/\/en.wikipedia.org\/wiki\/Smart_grid \"Smart grid\") [Smart growth](https:\/\/en.wikipedia.org\/wiki\/Smart_growth \"Smart growth\") [Stormwater](https:\/\/en.wikipedia.org\/wiki\/Stormwater \"Stormwater\") [Urban sprawl](https:\/\/en.wikipedia.org\/wiki\/Urban_sprawl \"Urban sprawl\") [Traffic congestion](https:\/\/en.wikipedia.org\/wiki\/Traffic_congestion \"Traffic congestion\") [Transit-oriented development](https:\/\/en.wikipedia.org\/wiki\/Transit-oriented_development \"Transit-oriented development\") [Fuel efficiency]() [Waste-to-energy](https:\/\/en.wikipedia.org\/wiki\/Waste-to-energy \"Waste-to-energy\") [Weatherization](https:\/\/en.wikipedia.org\/wiki\/Weatherization \"Weatherization\") [Wireless technology](https:\/\/en.wikipedia.org\/wiki\/Wireless \"Wireless\") |\n| Fields of study [Architecture](https:\/\/en.wikipedia.org\/wiki\/Architecture \"Architecture\") [Chemical engineering](https:\/\/en.wikipedia.org\/wiki\/Chemical_engineering \"Chemical engineering\") [Civil](https:\/\/en.wikipedia.org\/wiki\/Civil_engineering \"Civil engineering\") [Electrical](https:\/\/en.wikipedia.org\/wiki\/Electrical_engineering \"Electrical engineering\") [Mechanical engineering](https:\/\/en.wikipedia.org\/wiki\/Mechanical_engineering \"Mechanical engineering\") [Public economics](https:\/\/en.wikipedia.org\/wiki\/Public_economics \"Public economics\") [Public policy](https:\/\/en.wikipedia.org\/wiki\/Public_policy \"Public policy\") [Urban planning](https:\/\/en.wikipedia.org\/wiki\/Urban_planning \"Urban planning\") |\n| Examples [Akashi Kaikyo Bridge](https:\/\/en.wikipedia.org\/wiki\/Akashi_Kaikyo_Bridge \"Akashi Kaikyo Bridge\") [Trans-Alaska pipeline](https:\/\/en.wikipedia.org\/wiki\/Trans-Alaska_Pipeline_System \"Trans-Alaska Pipeline System\") [Autobahn](https:\/\/en.wikipedia.org\/wiki\/Autobahn \"Autobahn\") [Bicycle parking station](https:\/\/en.wikipedia.org\/wiki\/Bicycle_parking_station \"Bicycle parking station\") [Brazilian energy independence](https:\/\/en.wikipedia.org\/wiki\/Energy_in_Brazil \"Energy in Brazil\") [Brooklyn Bridge](https:\/\/en.wikipedia.org\/wiki\/Brooklyn_Bridge \"Brooklyn Bridge\") [Channel Tunnel](https:\/\/en.wikipedia.org\/wiki\/Channel_Tunnel \"Channel Tunnel\") [Chicago wastewater](https:\/\/en.wikipedia.org\/wiki\/Metropolitan_Water_Reclamation_District_of_Greater_Chicago \"Metropolitan Water Reclamation District of Greater Chicago\") [China's high-speed rail](https:\/\/en.wikipedia.org\/wiki\/High-speed_rail_in_China \"High-speed rail in China\") [Curtiba rapid bus transit](https:\/\/en.wikipedia.org\/wiki\/Rede_Integrada_de_Transporte \"Rede Integrada de Transporte\") [Cycling infrastructure](https:\/\/en.wikipedia.org\/wiki\/Cycling_infrastructure \"Cycling infrastructure\") ([history](https:\/\/en.wikipedia.org\/wiki\/History_of_cycling_infrastructure \"History of cycling infrastructure\"), [safety](https:\/\/en.wikipedia.org\/wiki\/Safety_of_cycling_infrastructure \"Safety of cycling infrastructure\")) [Danish wind-power](https:\/\/en.wikipedia.org\/wiki\/Wind_power_in_Denmark \"Wind power in Denmark\") [British offshore wind-power](https:\/\/en.wikipedia.org\/wiki\/List_of_offshore_wind_farms_in_the_United_Kingdom \"List of offshore wind farms in the United Kingdom\") [Nuclear power in France](https:\/\/en.wikipedia.org\/wiki\/Nuclear_power_in_France \"Nuclear power in France\") [Solar power in Germany](https:\/\/en.wikipedia.org\/wiki\/Solar_power_in_Germany \"Solar power in Germany\") [Hoover Dam](https:\/\/en.wikipedia.org\/wiki\/Hoover_Dam \"Hoover Dam\") [Hong Kong Int'l Airport](https:\/\/en.wikipedia.org\/wiki\/Hong_Kong_International_Airport \"Hong Kong International Airport\") [Intercity Express](https:\/\/en.wikipedia.org\/wiki\/Intercity_Express \"Intercity Express\") [Interstate highways](https:\/\/en.wikipedia.org\/wiki\/Interstate_Highway_System \"Interstate Highway System\") [Jamnagar Refinery](https:\/\/en.wikipedia.org\/wiki\/Jio-bp#Jamnagar_Refinery \"Jio-bp\") [Kansai Int'l Airport](https:\/\/en.wikipedia.org\/wiki\/Kansai_International_Airport \"Kansai International Airport\") [Levee](https:\/\/en.wikipedia.org\/wiki\/Levee \"Levee\") [Offshore wind port](https:\/\/en.wikipedia.org\/wiki\/Offshore_wind_port \"Offshore wind port\") [Panama Canal](https:\/\/en.wikipedia.org\/wiki\/Panama_Canal \"Panama Canal\") [Port of Shanghai](https:\/\/en.wikipedia.org\/wiki\/Port_of_Shanghai \"Port of Shanghai\") [San Francisco–Oakland Bay Bridge](https:\/\/en.wikipedia.org\/wiki\/San_Francisco%E2%80%93Oakland_Bay_Bridge \"San Francisco–Oakland Bay Bridge\") [Three Gorges Dam](https:\/\/en.wikipedia.org\/wiki\/Three_Gorges_Dam \"Three Gorges Dam\") [Shinkansen](https:\/\/en.wikipedia.org\/wiki\/Shinkansen \"Shinkansen\") [Spanish high-speed rail](https:\/\/en.wikipedia.org\/wiki\/High-speed_rail_in_Spain \"High-speed rail in Spain\") [French TGV rail](https:\/\/en.wikipedia.org\/wiki\/TGV \"TGV\") [Spanish autovias and autopistas](https:\/\/en.wikipedia.org\/wiki\/Highways_in_Spain \"Highways in Spain\") [Transcontinental Railroad](https:\/\/en.wikipedia.org\/wiki\/First_transcontinental_railroad \"First transcontinental railroad\") [Power transmission in the USA](https:\/\/en.wikipedia.org\/wiki\/Electric_power_transmission#Overhead_transmission \"Electric power transmission\") [Wind farm](https:\/\/en.wikipedia.org\/wiki\/Wind_farm \"Wind farm\") |\n| ![](https:\/\/upload.wikimedia.org\/wikipedia\/en\/thumb\/9\/96\/Symbol_category_class.svg\/20px-Symbol_category_class.svg.png) [Category](https:\/\/en.wikipedia.org\/wiki\/Category:Infrastructure \"Category:Infrastructure\") [![icon](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/7\/7a\/Nuvola_apps_kcmsystem.svg\/40px-Nuvola_apps_kcmsystem.svg.png)](https:\/\/en.wikipedia.org\/wiki\/File:Nuvola_apps_kcmsystem.svg) [Engineering portal](https:\/\/en.wikipedia.org\/wiki\/Portal:Engineering \"Portal:Engineering\") |\n| [v](https:\/\/en.wikipedia.org\/wiki\/Template:Infrastructure_sidebar \"Template:Infrastructure sidebar\") [t](https:\/\/en.wikipedia.org\/wiki\/Template_talk:Infrastructure_sidebar \"Template talk:Infrastructure sidebar\") [e](https:\/\/en.wikipedia.org\/wiki\/Special:EditPage\/Template:Infrastructure_sidebar \"Special:EditPage\/Template:Infrastructure sidebar\") |\n\n**Fuel efficiency** (or **fuel economy**) is a form of [thermal efficiency](https:\/\/en.wikipedia.org\/wiki\/Thermal_efficiency \"Thermal efficiency\"), meaning the [ratio](https:\/\/en.wikipedia.org\/wiki\/Ratio \"Ratio\") of effort to result of a process that converts [chemical](https:\/\/en.wikipedia.org\/wiki\/Chemical_energy \"Chemical energy\") [potential energy](https:\/\/en.wikipedia.org\/wiki\/Potential_energy \"Potential energy\") contained in a carrier ([fuel](https:\/\/en.wikipedia.org\/wiki\/Fuel \"Fuel\")) into kinetic energy or [work](https:\/\/en.wikipedia.org\/wiki\/Mechanical_work \"Mechanical work\"). Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous [energy profile](https:\/\/en.wikipedia.org\/wiki\/Energy_profile \"Energy profile\"). Non-transportation applications, such as [industry](https:\/\/en.wikipedia.org\/wiki\/Industrial_sector \"Industrial sector\"), benefit from increased fuel efficiency, especially [fossil fuel power plants](https:\/\/en.wikipedia.org\/wiki\/Fossil_fuel_power_plant \"Fossil fuel power plant\") or industries dealing with [combustion](https:\/\/en.wikipedia.org\/wiki\/Combustion \"Combustion\"), such as [ammonia](https:\/\/en.wikipedia.org\/wiki\/Ammonia \"Ammonia\") production during the [Haber process](https:\/\/en.wikipedia.org\/wiki\/Haber_process \"Haber process\").\n\nIn the context of [transport](https:\/\/en.wikipedia.org\/wiki\/Transport \"Transport\"), fuel economy is the [energy efficiency](https:\/\/en.wikipedia.org\/wiki\/Energy_efficiency_in_transportation \"Energy efficiency in transportation\") of a particular vehicle, given as a [ratio](https:\/\/en.wikipedia.org\/wiki\/Ratio \"Ratio\") of distance traveled per unit of [fuel](https:\/\/en.wikipedia.org\/wiki\/Motor_fuel \"Motor fuel\") consumed. It is dependent on several factors including [engine efficiency](https:\/\/en.wikipedia.org\/wiki\/Engine_efficiency \"Engine efficiency\"), [transmission](https:\/\/en.wikipedia.org\/wiki\/Transmission_\$mechanics\$ \"Transmission (mechanics)\") design, and [tire](https:\/\/en.wikipedia.org\/wiki\/Tire \"Tire\") design. In most countries, using the [metric system](https:\/\/en.wikipedia.org\/wiki\/Metric_system \"Metric system\"), fuel economy is stated as \"fuel consumption\" in [liters](https:\/\/en.wikipedia.org\/wiki\/Liter \"Liter\") per 100 [kilometers](https:\/\/en.wikipedia.org\/wiki\/Kilometers \"Kilometers\") (L\/100 km) or kilometers per liter (km\/L or kmpl). In a number of countries still using other systems, fuel economy is expressed in [miles](https:\/\/en.wikipedia.org\/wiki\/Mile \"Mile\") per [gallon](https:\/\/en.wikipedia.org\/wiki\/Gallon \"Gallon\") (mpg), for example in the US and usually also in the UK ([imperial](https:\/\/en.wikipedia.org\/wiki\/Imperial_units \"Imperial units\") gallon); there is sometimes confusion as the imperial gallon is 20% larger than the US gallon so that mpg values are not directly comparable. Traditionally, litres per [mil](https:\/\/en.wikipedia.org\/wiki\/Scandinavian_mile \"Scandinavian mile\") were used in [Norway](https:\/\/en.wikipedia.org\/wiki\/Norway \"Norway\") and [Sweden](https:\/\/en.wikipedia.org\/wiki\/Sweden \"Sweden\"), but both have aligned to the EU standard of L\/100 km.[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-1)\n\nFuel consumption is a more accurate measure of a vehicle's performance because it is a linear relationship while fuel economy leads to distortions in efficiency improvements.[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-2) Weight-specific efficiency (efficiency per unit weight) may be stated for [freight](https:\/\/en.wikipedia.org\/wiki\/Freight \"Freight\"), and passenger-specific efficiency (vehicle efficiency per passenger) for passenger vehicles.\n\n## Vehicle design\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=1 \"Edit section: Vehicle design\")\\]\n\nFuel efficiency is dependent on many parameters of a vehicle, including its [engine](https:\/\/en.wikipedia.org\/wiki\/Engine \"Engine\") parameters, [aerodynamic drag](https:\/\/en.wikipedia.org\/wiki\/Drag_\$physics\$ \"Drag (physics)\"), weight, AC usage, fuel and [rolling resistance](https:\/\/en.wikipedia.org\/wiki\/Rolling_resistance \"Rolling resistance\"). There have been advances in all areas of vehicle design in recent decades. Fuel efficiency of vehicles can also be improved by careful maintenance and driving habits.[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-3)\n\n[Hybrid vehicles](https:\/\/en.wikipedia.org\/wiki\/Hybrid_vehicles \"Hybrid vehicles\") use two or more power sources for propulsion. In many designs, a small combustion engine is combined with electric motors. Kinetic energy which would otherwise be lost to heat during braking is recaptured as electrical power to improve fuel efficiency. The larger batteries in these vehicles power the [car's electronics](https:\/\/en.wikipedia.org\/wiki\/Automotive_electronics \"Automotive electronics\"), allowing the engine to shut off and avoid prolonged [idling](https:\/\/en.wikipedia.org\/wiki\/Start-stop_system \"Start-stop system\").[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-4)\n\n## Fleet efficiency\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=2 \"Edit section: Fleet efficiency\")\\]\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/9\/90\/1975-_US_vehicle_production_share%2C_by_vehicle_type.svg\/250px-1975-_US_vehicle_production_share%2C_by_vehicle_type.svg.png)](https:\/\/en.wikipedia.org\/wiki\/File:1975-_US_vehicle_production_share,_by_vehicle_type.svg)\n\nTrucks' share of US vehicles produced, has tripled since 1975. Though vehicle fuel efficiency has increased within each category, the overall trend toward less efficient types of vehicles has offset some of the benefits of greater fuel economy and reduction in carbon dioxide emissions.[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-EPA_AutomotiveTrends_202212-5) Without the shift towards SUVs, energy use per unit distance could have fallen 30% more than it did from 2010 to 2022.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-GlobalFuelEfficInit_202311-6)\n\nFleet efficiency describes the average efficiency of a population of vehicles. Technological advances in efficiency may be offset by a change in buying habits with a propensity to heavier vehicles that are less fuel-efficient.[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-EPA_AutomotiveTrends_202212-5)\n\n## Energy efficiency terminology\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=3 \"Edit section: Energy efficiency terminology\")\\]\n\n[Energy efficiency](https:\/\/en.wikipedia.org\/wiki\/Energy_efficiency_\$physics\$ \"Energy efficiency (physics)\") is similar to fuel efficiency but the input is usually in units of energy such as [megajoules](https:\/\/en.wikipedia.org\/wiki\/Megajoules \"Megajoules\") (MJ), [kilowatt-hours](https:\/\/en.wikipedia.org\/wiki\/Kilowatt-hours \"Kilowatt-hours\") (kW·h), kilocalories (kcal) or [British thermal units](https:\/\/en.wikipedia.org\/wiki\/British_thermal_units \"British thermal units\") (BTU). The inverse of \"energy efficiency\" is \"[energy intensity](https:\/\/en.wikipedia.org\/wiki\/Energy_intensity \"Energy intensity\")\", or the amount of input energy required for a unit of output such as MJ\/passenger-km (of passenger transport), BTU\/ton-mile or kJ\/t-km (of freight transport), GJ\/t (for production of steel and other materials), BTU\/(kW·h) (for electricity generation), or litres\/100 km (of vehicle travel). Litres per 100 km is also a measure of \"energy intensity\" where the input is measured by the amount of fuel and the output is measured by the [distance](https:\/\/en.wikipedia.org\/wiki\/Distance \"Distance\") travelled. For example: [Fuel economy in automobiles](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy_in_automobiles \"Fuel economy in automobiles\").\n\nGiven a heat value of a fuel, it would be trivial to convert from fuel units (such as litres of gasoline) to energy units (such as MJ) and conversely. But there are two problems with comparisons made using energy units:\n\n- There are two different heat values for any hydrogen-containing fuel which can differ by several percent (see below).\n- When comparing transportation energy costs, a [kilowatt hour](https:\/\/en.wikipedia.org\/wiki\/Kilowatt_hour \"Kilowatt hour\") of electric energy may require an amount of fuel with heating value of 2 or 3 kilowatt hours to produce it.\n\n## Energy content of fuel\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=4 \"Edit section: Energy content of fuel\")\\]\n\nThe specific [energy content](https:\/\/en.wikipedia.org\/wiki\/Energy_content \"Energy content\") of a fuel is the heat energy obtained when a certain quantity is burned (such as a gallon, litre, kilogram). It is sometimes called the [heat of combustion](https:\/\/en.wikipedia.org\/wiki\/Heat_of_combustion \"Heat of combustion\"). There exists two different values of [specific heat](https:\/\/en.wikipedia.org\/wiki\/Specific_heat \"Specific heat\") energy for the same batch of fuel. One is the high (or gross) heat of combustion and the other is the low (or net) heat of combustion. The high value is obtained when, after the combustion, the water in the exhaust is in liquid form. For the low value, the exhaust has all the water in vapor form (steam). Since water vapor gives up heat energy when it changes from vapor to liquid, the liquid water value is larger since it includes the [latent heat](https:\/\/en.wikipedia.org\/wiki\/Latent_heat \"Latent heat\") of vaporization of water. The difference between the high and low values is significant, about 8 or 9%. This accounts for most of the apparent discrepancy in the heat value of gasoline. In the U.S. (and the table) the high heat values have traditionally been used, but in many other countries, the low heat values are commonly used.\n\n| Fuel type | MJ\/L | MJ\/kg | [BTU](https:\/\/en.wikipedia.org\/wiki\/British_thermal_unit \"British thermal unit\")\/[imp gal](https:\/\/en.wikipedia.org\/wiki\/Gallon \"Gallon\") | BTU\/[US gal](https:\/\/en.wikipedia.org\/wiki\/US_gallon \"US gallon\") | [Research octane  number (RON)](https:\/\/en.wikipedia.org\/wiki\/Octane_rating \"Octane rating\") |\n|---|---|---|---|---|---|\n| Regular [gasoline](https:\/\/en.wikipedia.org\/wiki\/Gasoline \"Gasoline\")\/petrol | 34\\.8 | ~47 | 150,100 | 125,000 | Min. 91 |\n| Premium [gasoline](https:\/\/en.wikipedia.org\/wiki\/Gasoline \"Gasoline\")\/petrol |   | ~46 |   |   | Min. 95 |\n| [Autogas](https:\/\/en.wikipedia.org\/wiki\/Autogas \"Autogas\") ([LPG](https:\/\/en.wikipedia.org\/wiki\/Liquefied_petroleum_gas \"Liquefied petroleum gas\")) (60% [propane](https:\/\/en.wikipedia.org\/wiki\/Propane \"Propane\") and 40% [butane](https:\/\/en.wikipedia.org\/wiki\/Butane \"Butane\")) | 25\\.5–28.7 | ~51 |   |   | 108–110 |\n| [Ethanol](https:\/\/en.wikipedia.org\/wiki\/Ethanol_fuel \"Ethanol fuel\") | 23\\.5 | 31\\.1[\\[7\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-7) | 101,600 | 84,600 | 129 |\n| [Methanol](https:\/\/en.wikipedia.org\/wiki\/Methanol \"Methanol\") | 17\\.9 | 19\\.9 | 77,600 | 64,600 | 123 |\n| [Gasohol](https:\/\/en.wikipedia.org\/wiki\/Alcohol_fuel \"Alcohol fuel\") (10% ethanol and 90% gasoline) | 33\\.7 | ~45 | 145,200 | 121,000 | 93\/94 |\n| [E85](https:\/\/en.wikipedia.org\/wiki\/E85 \"E85\") (85% ethanol and 15% gasoline) | 25\\.2 | ~33 | 108,878 | 90,660 | 100–105 |\n| [Diesel](https:\/\/en.wikipedia.org\/wiki\/Diesel_fuel \"Diesel fuel\") | 38\\.6 | ~48 | 166,600 | 138,700 | [N\/A (see cetane)](https:\/\/en.wikipedia.org\/wiki\/Cetane_number \"Cetane number\") |\n| [Biodiesel](https:\/\/en.wikipedia.org\/wiki\/Biodiesel \"Biodiesel\") | 35\\.1 | 39\\.9 | 151,600 | 126,200 | [N\/A (see cetane)](https:\/\/en.wikipedia.org\/wiki\/Cetane_number \"Cetane number\") |\n| [Vegetable oil](https:\/\/en.wikipedia.org\/wiki\/WVO \"WVO\") (using 9.00 kcal\/g) | 34\\.3 | 37\\.7 | 147,894 | 123,143 |   |\n| [Aviation gasoline](https:\/\/en.wikipedia.org\/wiki\/Aviation_gasoline \"Aviation gasoline\") | 33\\.5 | 46\\.8 | 144,400 | 120,200 | 80-145 |\n| [Jet fuel](https:\/\/en.wikipedia.org\/wiki\/Jet_fuel \"Jet fuel\"), naphtha | 35\\.5 | 46\\.6 | 153,100 | 127,500 | N\/A to turbine engines |\n| [Jet fuel](https:\/\/en.wikipedia.org\/wiki\/Jet_fuel \"Jet fuel\"), kerosene | 37\\.6 | ~47 | 162,100 | 135,000 | N\/A to turbine engines |\n| [Liquefied natural gas](https:\/\/en.wikipedia.org\/wiki\/Liquefied_natural_gas \"Liquefied natural gas\") | 25\\.3 | ~55 | 109,000 | 90,800 |   |\n| [Liquid hydrogen](https:\/\/en.wikipedia.org\/wiki\/Liquid_hydrogen \"Liquid hydrogen\") | 09\\.3 | ~130 | 40,467 | 33,696 |   |\n\n[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-TEDB-8)\n\nNeither the gross heat of combustion nor the net heat of combustion gives the theoretical amount of mechanical energy (work) that can be obtained from the reaction. (This is given by the change in [Gibbs free energy](https:\/\/en.wikipedia.org\/wiki\/Gibbs_free_energy \"Gibbs free energy\"), and is around 45.7 MJ\/kg for gasoline.) The actual amount of mechanical work obtained from fuel (the inverse of the [specific fuel consumption](https:\/\/en.wikipedia.org\/wiki\/Brake-specific_fuel_consumption \"Brake-specific fuel consumption\")) depends on the engine. A figure of 17.6 MJ\/kg is possible with a gasoline engine, and 19.1 MJ\/kg for a diesel engine. See [Brake-specific fuel consumption](https:\/\/en.wikipedia.org\/wiki\/Brake-specific_fuel_consumption \"Brake-specific fuel consumption\") for more information.\\[*[clarification needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Please_clarify \"Wikipedia:Please clarify\")*\\]\n\n## Transportation\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=5 \"Edit section: Transportation\")\\]\n\nThis section is an excerpt from [Energy efficiency in transport](https:\/\/en.wikipedia.org\/wiki\/Energy_efficiency_in_transport \"Energy efficiency in transport\").\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Energy_efficiency_in_transport&action=edit)\\]\n\nThe [energy efficiency in transport](https:\/\/en.wikipedia.org\/wiki\/Energy_efficiency_in_transport \"Energy efficiency in transport\") is the useful travelled [distance](https:\/\/en.wikipedia.org\/wiki\/Distance \"Distance\"), of passengers, goods or any type of load; divided by the total [energy](https:\/\/en.wikipedia.org\/wiki\/Energy \"Energy\") put into the transport [propulsion](https:\/\/en.wikipedia.org\/wiki\/Propulsion \"Propulsion\") means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in [liquid fuels](https:\/\/en.wikipedia.org\/wiki\/Liquid_fuel \"Liquid fuel\"), [electrical energy](https:\/\/en.wikipedia.org\/wiki\/Electrical_energy \"Electrical energy\") or [food energy](https:\/\/en.wikipedia.org\/wiki\/Food_energy \"Food energy\").[\\[9\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-9)[\\[10\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_fueleco-10) The [energy efficiency](https:\/\/en.wikipedia.org\/wiki\/Efficient_energy_use \"Efficient energy use\") is also occasionally known as [energy intensity](https:\/\/en.wikipedia.org\/wiki\/Energy_intensity \"Energy intensity\").[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_DOEgloss-11) The [inverse](https:\/\/en.wikipedia.org\/wiki\/Multiplicative_inverse \"Multiplicative inverse\") of the energy efficiency in transport is the energy consumption in transport.\n\nEnergy efficiency in transport is often described in terms of [fuel consumption](https:\/\/en.wikipedia.org\/wiki\/Fuel_consumption \"Fuel consumption\"), fuel consumption being the reciprocal of fuel economy.[\\[10\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_fueleco-10) Nonetheless, fuel consumption is linked with a means of propulsion which uses [liquid fuels](https:\/\/en.wikipedia.org\/wiki\/Liquid_fuel \"Liquid fuel\"), whilst energy efficiency is applicable to any sort of propulsion. To avoid said confusion, and to be able to compare the energy efficiency in any type of vehicle, experts tend to measure the energy in the [International System of Units](https:\/\/en.wikipedia.org\/wiki\/International_System_of_Units \"International System of Units\"), i.e., [joules](https:\/\/en.wikipedia.org\/wiki\/Joule \"Joule\").\n\nTherefore, in the International System of Units, the energy efficiency in transport is measured in terms of metre per joule, or m\/J, while the energy consumption in transport is measured in terms of joules per metre, or J\/m. The more efficient the vehicle, the more metres it covers with one joule (more efficiency), or the fewer joules it uses to travel over one metre (less consumption). The [energy efficiency](https:\/\/en.wikipedia.org\/wiki\/Efficient_energy_use \"Efficient energy use\") in transport largely varies by means of transport. Different types of [transport](https:\/\/en.wikipedia.org\/wiki\/Transportation \"Transportation\") range from some hundred [kilojoules](https:\/\/en.wikipedia.org\/wiki\/Joule \"Joule\") per kilometre (kJ\/km) for a [bicycle](https:\/\/en.wikipedia.org\/wiki\/Bicycle \"Bicycle\") to tens of megajoules per kilometre (MJ\/km) for a [helicopter](https:\/\/en.wikipedia.org\/wiki\/Helicopter \"Helicopter\").\n\nVia type of fuel used and rate of fuel consumption, energy efficiency is also often related to operating cost (\\$\/km) and environmental emissions (e.g. CO2\/km).\n\n### Fuel efficiency of motor vehicles\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=6 \"Edit section: Fuel efficiency of motor vehicles\")\\]\n\nThis section is an excerpt from [Fuel economy in automobiles](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy_in_automobiles \"Fuel economy in automobiles\").\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_economy_in_automobiles&action=edit)\\]\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/3\/38\/CAFE_performance.svg\/250px-CAFE_performance.svg.png)](https:\/\/en.wikipedia.org\/wiki\/File:CAFE_performance.svg)\n\nNew light-duty vehicle fuel economy by vehicle type from vehicle manufacturers in the United States, in miles per gallon (1975 - 2019)\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/3\/35\/2006_Honda_Airwave_fuel_efficiency_meter.jpg\/250px-2006_Honda_Airwave_fuel_efficiency_meter.jpg)](https:\/\/en.wikipedia.org\/wiki\/File:2006_Honda_Airwave_fuel_efficiency_meter.jpg)\n\nFuel consumption monitor from a 2006 [Honda Airwave](https:\/\/en.wikipedia.org\/wiki\/Honda_Airwave \"Honda Airwave\"). The displayed fuel economy is 18.1 km\/L (5.5 L\/100 km; 43 mpg‑US).\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/0\/02\/Fuel_Economy%2C_1916.jpg\/250px-Fuel_Economy%2C_1916.jpg)](https:\/\/en.wikipedia.org\/wiki\/File:Fuel_Economy,_1916.jpg)\n\nA [Briggs and Stratton Flyer](https:\/\/en.wikipedia.org\/wiki\/Briggs_and_Stratton_Flyer \"Briggs and Stratton Flyer\") from 1916. Originally an experiment in creating a fuel-saving automobile in the United States, the vehicle weighed only 135 lb (61.2 kg) and was an adaptation of a small gasoline engine originally designed to power a bicycle.[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-12)\n\nThe [fuel economy](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy_in_automobiles \"Fuel economy in automobiles\") or fuel efficiency of an [automobile](https:\/\/en.wikipedia.org\/wiki\/Car \"Car\") relates to the [distance traveled](https:\/\/en.wikipedia.org\/wiki\/Distance_traveled \"Distance traveled\") by a vehicle and the amount of [fuel](https:\/\/en.wikipedia.org\/wiki\/Fuel \"Fuel\") consumed. It can be expressed in terms of the volume of fuel to travel a given distance, such as in litres per 100 kilometres (L\/100 km), or through its inverse, the distance traveled per unit volume of fuel consumed, as in kilometres per litre (km\/L) or miles per gallon (mpg). Since fuel economy of vehicles is a significant factor in [air pollution](https:\/\/en.wikipedia.org\/wiki\/Air_pollution \"Air pollution\"), the importation of [motor fuel](https:\/\/en.wikipedia.org\/wiki\/Motor_fuel \"Motor fuel\") can be a large part of a nation's [foreign trade](https:\/\/en.wikipedia.org\/wiki\/Foreign_trade \"Foreign trade\") and consumers frequently undervalue fuel efficiency, many countries impose requirements for fuel economy.\n\nDifferent methods are used to approximate the actual performance of the vehicle. The energy in fuel is required to overcome various losses ([wind resistance](https:\/\/en.wikipedia.org\/wiki\/Wind_resistance \"Wind resistance\"), [tire drag](https:\/\/en.wikipedia.org\/wiki\/Tire_drag \"Tire drag\"), and others) encountered while propelling the vehicle, and in providing power to vehicle systems such as ignition or air conditioning. Various strategies can be employed to reduce losses at each of the conversions between the [chemical energy](https:\/\/en.wikipedia.org\/wiki\/Chemical_energy \"Chemical energy\") in the fuel and the [kinetic energy](https:\/\/en.wikipedia.org\/wiki\/Kinetic_energy \"Kinetic energy\") of the vehicle. Driver behavior can affect fuel economy; maneuvers such as sudden acceleration and heavy [braking](https:\/\/en.wikipedia.org\/wiki\/Braking \"Braking\") waste energy.\n\n[Electric cars](https:\/\/en.wikipedia.org\/wiki\/Electric_car \"Electric car\") use [kilowatt-hours](https:\/\/en.wikipedia.org\/wiki\/Kilowatt-hours \"Kilowatt-hours\") of electricity per 100 kilometres (kWh\/100km); in the U.S., an equivalence measure, such as [miles per gallon gasoline equivalent](https:\/\/en.wikipedia.org\/wiki\/Miles_per_gallon_gasoline_equivalent \"Miles per gallon gasoline equivalent\") (US gallon) has been created to attempt to compare them.\n\n### Driving technique\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=7 \"Edit section: Driving technique\")\\]\n\nThis section is an excerpt from [Energy-efficient driving](https:\/\/en.wikipedia.org\/wiki\/Energy-efficient_driving \"Energy-efficient driving\").\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Energy-efficient_driving&action=edit)\\]\n\n[Energy-efficient driving](https:\/\/en.wikipedia.org\/wiki\/Energy-efficient_driving \"Energy-efficient driving\") techniques are used by drivers who wish to reduce their fuel consumption, and thus maximize fuel efficiency. Many drivers have the potential to improve their fuel efficiency significantly.[\\[13\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy-efficient_driving_Beusen-13) Simple things such as keeping tires properly inflated, having a vehicle well-maintained and avoiding idling can dramatically improve fuel efficiency.[\\[14\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-14) Careful use of acceleration and deceleration and especially limiting use of high speeds helps efficiency. The use of multiple such techniques is called \"[hypermiling](https:\/\/en.wikipedia.org\/wiki\/Hypermiling \"Hypermiling\")\".[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy-efficient_driving_merriam-webster.com-15)\n\nWhile these techniques can be applied by any driver, energy-efficient driving (often called \"eco-driving\") has become a major focus of modern [fleet management](https:\/\/en.wikipedia.org\/wiki\/Fleet_management \"Fleet management\"). As a key part of [fleet digitalization](https:\/\/en.wikipedia.org\/wiki\/Fleet_digitalization \"Fleet digitalization\"), companies use [telematics](https:\/\/en.wikipedia.org\/wiki\/Telematics \"Telematics\") to automatically monitor and manage fuel economy. A [fleet telematics system](https:\/\/en.wikipedia.org\/wiki\/Fleet_telematics_system \"Fleet telematics system\") collects data on behaviors that waste fuel, such as harsh acceleration, speeding, and idling. This information is then used in [driver scoring](https:\/\/en.wikipedia.org\/wiki\/Driver_scoring \"Driver scoring\") applications to identify and coach drivers.[\\[13\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy-efficient_driving_Beusen-13) This is often combined with dedicated [fuel-management systems](https:\/\/en.wikipedia.org\/wiki\/Fuel-management_systems \"Fuel-management systems\") that use high-precision [fuel level sensors](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_level_sensor&action=edit&redlink=1 \"Fuel level sensor (page does not exist)\") to get exact fuel consumption data and prevent [gasoline theft](https:\/\/en.wikipedia.org\/wiki\/Gasoline_theft \"Gasoline theft\").[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-16)\n\nSimple fuel-efficiency techniques can result in reduction in fuel consumption without resorting to radical fuel-saving techniques that can be unlawful and dangerous, such as tailgating larger vehicles.\n\n## Advanced technology\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=8 \"Edit section: Advanced technology\")\\]\n\nThe most efficient machines for converting energy to rotary motion are electric motors, as used in [electric vehicles](https:\/\/en.wikipedia.org\/wiki\/Electric_vehicles \"Electric vehicles\"). However, electricity is not a primary energy source so the efficiency of the electricity production has also to be taken into account. [Railway](https:\/\/en.wikipedia.org\/wiki\/Railway \"Railway\") trains can be powered using electricity, delivered through an additional running rail, overhead [catenary](https:\/\/en.wikipedia.org\/wiki\/Overhead_lines \"Overhead lines\") system or by on-board generators used in [diesel-electric](https:\/\/en.wikipedia.org\/wiki\/Diesel-electric_transmission \"Diesel-electric transmission\") locomotives as common on the US and UK rail networks. Pollution produced from centralised generation of electricity is emitted at a distant power station, rather than \"on site\". Pollution can be reduced by using more railway electrification and [low carbon power](https:\/\/en.wikipedia.org\/wiki\/Low_carbon_power \"Low carbon power\") for electricity. Some railways, such as the French SNCF and Swiss federal railways derive most, if not 100% of their power, from hydroelectric or nuclear power stations, therefore atmospheric pollution from their rail networks is very low. This was reflected in a study by AEA Technology between a [Eurostar](https:\/\/en.wikipedia.org\/wiki\/Eurostar \"Eurostar\") train and airline journeys between London and Paris, which showed the trains on average emitting 10 times less CO2, per passenger, than planes, helped in part by French nuclear generation.[\\[17\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-17)\n\n### Hydrogen fuel cells\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=9 \"Edit section: Hydrogen fuel cells\")\\]\n\nIn the future, [hydrogen cars](https:\/\/en.wikipedia.org\/wiki\/Hydrogen_vehicle \"Hydrogen vehicle\") may be commercially available. Toyota is test-marketing vehicles powered by hydrogen fuel cells in southern California, where a series of hydrogen fueling stations has been established. Powered either through chemical reactions in a [fuel cell](https:\/\/en.wikipedia.org\/wiki\/Fuel_cell \"Fuel cell\") that create electricity to drive very efficient electrical motors or by directly burning hydrogen in a combustion engine (near identically to a [natural gas vehicle](https:\/\/en.wikipedia.org\/wiki\/Natural_gas_vehicle \"Natural gas vehicle\"), and similarly compatible with both natural gas and gasoline); these vehicles promise to have near-zero pollution from the tailpipe (exhaust pipe). Potentially the atmospheric pollution could be minimal, provided the hydrogen is made by [electrolysis](https:\/\/en.wikipedia.org\/wiki\/Electrolysis \"Electrolysis\") using electricity from non-polluting sources such as solar, wind or [hydroelectricity](https:\/\/en.wikipedia.org\/wiki\/Hydroelectricity \"Hydroelectricity\") or nuclear. Commercial [hydrogen production](https:\/\/en.wikipedia.org\/wiki\/Hydrogen_production \"Hydrogen production\") uses fossil fuels and produces more carbon dioxide than hydrogen.\n\nBecause there are pollutants involved in the manufacture and destruction of a car and the production, transmission and storage of electricity and hydrogen, the label \"zero pollution\" applies only to the car's conversion of stored energy into movement.\n\nIn 2004, a consortium of major auto-makers — [BMW](https:\/\/en.wikipedia.org\/wiki\/BMW \"BMW\"), [General Motors](https:\/\/en.wikipedia.org\/wiki\/General_Motors \"General Motors\"), [Honda](https:\/\/en.wikipedia.org\/wiki\/Honda \"Honda\"), [Toyota](https:\/\/en.wikipedia.org\/wiki\/Toyota \"Toyota\") and [Volkswagen](https:\/\/en.wikipedia.org\/wiki\/Volkswagen \"Volkswagen\")\/[Audi](https:\/\/en.wikipedia.org\/wiki\/Audi \"Audi\") — came up with *\"Top Tier Detergent Gasoline Standard\"* to [gasoline](https:\/\/en.wikipedia.org\/wiki\/Gasoline \"Gasoline\") brands in the US and Canada that meet their minimum standards for [detergent](https:\/\/en.wikipedia.org\/wiki\/Detergent \"Detergent\") content[\\[18\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Top_Tier_Gasoline-18) and do not contain metallic additives. Top Tier gasoline contains higher levels of detergent additives in order to prevent the build-up of deposits (typically, on [fuel injector](https:\/\/en.wikipedia.org\/wiki\/Fuel_injector \"Fuel injector\") and [intake valve](https:\/\/en.wikipedia.org\/wiki\/Intake_valve \"Intake valve\")) known to reduce fuel economy and engine performance.[\\[19\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-19)\n\n### In microgravity\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=10 \"Edit section: In microgravity\")\\]\n\nHow fuel combusts affects how much energy is produced. The [National Aeronautics and Space Administration](https:\/\/en.wikipedia.org\/wiki\/National_Aeronautics_and_Space_Administration \"National Aeronautics and Space Administration\") (NASA) has investigated fuel consumption in [microgravity](https:\/\/en.wikipedia.org\/wiki\/Microgravity \"Microgravity\").\n\nThe common distribution of a flame under normal gravity conditions depends on [convection](https:\/\/en.wikipedia.org\/wiki\/Convection \"Convection\"), because soot tends to rise to the top of a flame, such as in a candle, making the flame yellow. In microgravity or [zero gravity](https:\/\/en.wikipedia.org\/wiki\/Zero_gravity \"Zero gravity\"), such as an environment in [outer space](https:\/\/en.wikipedia.org\/wiki\/Outer_space \"Outer space\"), convection no longer occurs, and the flame becomes [spherical](https:\/\/en.wikipedia.org\/wiki\/Sphere \"Sphere\"), with a tendency to become more blue and more efficient. There are several possible explanations for this difference, of which the most likely one given is the hypothesis that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs., National Aeronautics and Space Administration, April 2005. Experiments by NASA in microgravity reveal that [diffusion flames](https:\/\/en.wikipedia.org\/wiki\/Diffusion_flame \"Diffusion flame\") in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions.[LSP-1 experiment results](https:\/\/web.archive.org\/web\/20070312020123\/http:\/\/microgravity.grc.nasa.gov\/combustion\/lsp\/lsp1_results.htm), National Aeronautics and Space Administration, April 2005. [Premixed flames](https:\/\/en.wikipedia.org\/wiki\/Premixed_flame \"Premixed flame\") in microgravity burn at a much slower rate and more efficiently than even a candle on Earth, and last much longer.[\\[20\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-20)\n\n## See also\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=11 \"Edit section: See also\")\\]\n\n- [![icon](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/1\/14\/Crystal_energy.svg\/40px-Crystal_energy.svg.png)](https:\/\/en.wikipedia.org\/wiki\/File:Crystal_energy.svg)[Energy portal](https:\/\/en.wikipedia.org\/wiki\/Portal:Energy \"Portal:Energy\")\n\n- [Annual fuel utilization efficiency](https:\/\/en.wikipedia.org\/wiki\/Annual_fuel_utilization_efficiency \"Annual fuel utilization efficiency\") (AFUE)\n- [ACEA agreement](https:\/\/en.wikipedia.org\/wiki\/ACEA_agreement \"ACEA agreement\")\n- [Alternative propulsion](https:\/\/en.wikipedia.org\/wiki\/Alternative_propulsion \"Alternative propulsion\")\n- [Camless piston engine](https:\/\/en.wikipedia.org\/wiki\/Camless_piston_engine \"Camless piston engine\")\n- [Carbon dioxide equivalent](https:\/\/en.wikipedia.org\/wiki\/Carbon_dioxide_equivalent \"Carbon dioxide equivalent\")\n- [Corporate Average Fuel Economy](https:\/\/en.wikipedia.org\/wiki\/Corporate_Average_Fuel_Economy \"Corporate Average Fuel Economy\") (CAFE)\n- [EcoAuto](https:\/\/en.wikipedia.org\/wiki\/EcoAuto \"EcoAuto\") (in Canada)\n- [Efficient energy use](https:\/\/en.wikipedia.org\/wiki\/Efficient_energy_use \"Efficient energy use\")\n- [Emission standard](https:\/\/en.wikipedia.org\/wiki\/Emission_standard \"Emission standard\")\n- [Energy content of Biofuel](https:\/\/en.wikipedia.org\/wiki\/Energy_content_of_Biofuel \"Energy content of Biofuel\")\n- [Energy conservation](https:\/\/en.wikipedia.org\/wiki\/Energy_conservation \"Energy conservation\")\n- [Energy conversion efficiency](https:\/\/en.wikipedia.org\/wiki\/Energy_conversion_efficiency \"Energy conversion efficiency\")\n- [Energy density](https:\/\/en.wikipedia.org\/wiki\/Energy_density \"Energy density\")\n- [FF layout](https:\/\/en.wikipedia.org\/wiki\/FF_layout \"FF layout\")\n- [Front-wheel drive](https:\/\/en.wikipedia.org\/wiki\/Front-wheel_drive \"Front-wheel drive\")\n- [Fuel economy in aircraft](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy_in_aircraft \"Fuel economy in aircraft\")\n- [Fuel economy in automobiles](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy_in_automobiles \"Fuel economy in automobiles\")\n- [Fuel economy maximising behaviors](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy-maximizing_behaviors \"Fuel economy-maximizing behaviors\")\n- [Fuel efficiency in transportation](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency_in_transportation \"Fuel efficiency in transportation\")\n- [Gas-guzzler](https:\/\/en.wikipedia.org\/wiki\/Gas-guzzler \"Gas-guzzler\")\n- [Heating value](https:\/\/en.wikipedia.org\/wiki\/Heating_value \"Heating value\")\n- [Jevons paradox](https:\/\/en.wikipedia.org\/wiki\/Jevons_paradox \"Jevons paradox\")\n- [Life cycle assessment](https:\/\/en.wikipedia.org\/wiki\/Life_cycle_assessment \"Life cycle assessment\")\n- [Low-rolling resistance tires](https:\/\/en.wikipedia.org\/wiki\/Low-rolling_resistance_tires \"Low-rolling resistance tires\")\n- [Miles per gallon gasoline equivalent](https:\/\/en.wikipedia.org\/wiki\/Miles_per_gallon_gasoline_equivalent \"Miles per gallon gasoline equivalent\")\n- [Marine fuel management](https:\/\/en.wikipedia.org\/wiki\/Marine_fuel_management \"Marine fuel management\")\n- [Twinjet](https:\/\/en.wikipedia.org\/wiki\/Twinjet \"Twinjet\")\n- [Variable valve timing](https:\/\/en.wikipedia.org\/wiki\/Variable_valve_timing \"Variable valve timing\")\n- [Unibody](https:\/\/en.wikipedia.org\/wiki\/Vehicle_frame#Unibody \"Vehicle frame\")\n- [Automobile costs](https:\/\/en.wikipedia.org\/wiki\/Automobile_costs \"Automobile costs\")\n- [Vehicle metrics](https:\/\/en.wikipedia.org\/wiki\/Vehicle_metrics \"Vehicle metrics\")\n\n## References\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=12 \"Edit section: References\")\\]\n\n1. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-1)**\n   [\"Information on the fuel consumption of new cars\"](https:\/\/web.archive.org\/web\/20190908124154\/http:\/\/www.bilsweden.se\/miljo-sakerhet\/miljo\/information-gallande-bransleforbrukning-for-nya-bilar). Archived from [the original](http:\/\/www.bilsweden.se\/miljo-sakerhet\/miljo\/information-gallande-bransleforbrukning-for-nya-bilar) on 8 September 2019. Retrieved 7 November 2019.\n2. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-2)**\n   [\"Learn More About the Fuel Economy Label for Gasoline Vehicles\"](https:\/\/www.fueleconomy.gov\/feg\/label\/learn-more-gasoline-label.shtml#fuel-consumption-rate). [Archived](https:\/\/web.archive.org\/web\/20130705143242\/http:\/\/www.fueleconomy.gov\/feg\/label\/learn-more-gasoline-label.shtml#fuel-consumption-rate) from the original on 2013-07-05.\n3. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-3)**\n   [\"Simple tips and tricks to increase fuel efficiency of your car \\| CarSangrah\"](https:\/\/www.carsangrah.com\/blog\/simple-tips-tricks-enhance-fuel-efficiency-car). *CarSangrah*. 2018-06-07. Retrieved 2018-07-24.\n4. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-4)**\n   [\"How Hybrids Work\"](https:\/\/www.fueleconomy.gov\/). [U.S. Department of Energy](https:\/\/en.wikipedia.org\/wiki\/U.S._Department_of_Energy \"U.S. Department of Energy\"). [Archived](https:\/\/web.archive.org\/web\/20150708093450\/http:\/\/www.fueleconomy.gov\/) from the original on 2015-07-08. Retrieved 2014-01-16.\n5. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-EPA_AutomotiveTrends_202212_5-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-EPA_AutomotiveTrends_202212_5-1)\n   [\"Highlights of the Automotive Trends Report\"](https:\/\/www.epa.gov\/automotive-trends\/highlights-automotive-trends-report). *EPA.gov*. U.S. Environmental Protection Agency (EPA). 12 December 2022. [Archived](https:\/\/web.archive.org\/web\/20230902145941\/https:\/\/www.epa.gov\/automotive-trends\/highlights-automotive-trends-report) from the original on 2 September 2023.\n6. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-GlobalFuelEfficInit_202311_6-0)**\n   Cazzola, Pierpaolo; Paoli, Leonardo; Teter, Jacob (November 2023). [\"Trends in the Global Vehicle Fleet 2023 \/ Managing the SUV Shift and the EV Transition\"](https:\/\/www.globalfueleconomy.org\/media\/792523\/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf) (PDF). Global Fuel Economy Initiative (GFEI). p. 3. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\$identifier\$ \"Doi (identifier)\"):[10\\.7922\/G2HM56SV](https:\/\/doi.org\/10.7922%2FG2HM56SV). [Archived](https:\/\/web.archive.org\/web\/20231126092826\/https:\/\/www.globalfueleconomy.org\/media\/792523\/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf) (PDF) from the original on 26 November 2023.\n7. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-7)** Calculated from heats of formation. Does not correspond exactly to the figure for MJ\/L divided by density.\n8. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-TEDB_8-0)** [Appendix B, Transportation Energy Data Book](http:\/\/www-cta.ornl.gov\/data\/Appendix_B.html) from the [Center for Transportation Analysis](https:\/\/en.wikipedia.org\/wiki\/Center_for_Transportation_Analysis \"Center for Transportation Analysis\") of the [Oak Ridge National Laboratory](https:\/\/en.wikipedia.org\/wiki\/Oak_Ridge_National_Laboratory \"Oak Ridge National Laboratory\")\n9. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-9)**\n   [\"Efficiency\"](http:\/\/www.merriam-webster.com\/dictionary\/efficiency). Retrieved 18 September 2016.\n10. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_fueleco_10-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_fueleco_10-1)\n    [*Assessment of Fuel Economy Technologies for Light-duty Vehicles*](http:\/\/www.nap.edu\/read\/12924\/chapter\/4). The National Academies Press. 2011. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\$identifier\$ \"Doi (identifier)\"):[10\\.17226\/12924](https:\/\/doi.org\/10.17226%2F12924). [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\$identifier\$ \"ISBN (identifier)\")\n    \n    [978-0-309-15607-3](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0-309-15607-3 \"Special:BookSources\/978-0-309-15607-3\")\n    \n    . Retrieved 18 September 2016.\n11. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_DOEgloss_11-0)**\n    [\"Glossary of energy-related terms\"](http:\/\/energy.gov\/eere\/energybasics\/articles\/glossary-energy-related-terms#E). [U.S. Department of Energy](https:\/\/en.wikipedia.org\/wiki\/U.S._Department_of_Energy \"U.S. Department of Energy\"). Retrieved 20 September 2016.\n12. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-12)**\n    Page, Walter Hines; Page, Arthur Wilson (1916). [\"Man and His Machines\"](https:\/\/books.google.com\/books?id=lPAMVa7esS4C). *The World's Work*. Vol. XXXIII. Garden City, New York: Doubleday, Page & Co.\n13. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy-efficient_driving_Beusen_13-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy-efficient_driving_Beusen_13-1)\n    Beusen; et al. (2009). [\"Using on-board logging devices to study the long-term impact of an eco-driving course\"](https:\/\/www.researchgate.net\/publication\/231614817). *Transportation Research D*. **14** (7): 514–520\\. [Bibcode](https:\/\/en.wikipedia.org\/wiki\/Bibcode_\$identifier\$ \"Bibcode (identifier)\"):[2009TRPD...14..514B](https:\/\/ui.adsabs.harvard.edu\/abs\/2009TRPD...14..514B). [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\$identifier\$ \"Doi (identifier)\"):[10\\.1016\/j.trd.2009.05.009](https:\/\/doi.org\/10.1016%2Fj.trd.2009.05.009). [Archived](https:\/\/web.archive.org\/web\/20131019115218\/http:\/\/www.researchgate.net\/publication\/231614817_Using_on-board_logging_devices_to_study_the_long-term_impact_of_an_eco-driving_course?ev=prf_pub) from the original on 2013-10-19.\n14. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-14)**\n    [\"20 Ways to Improve Your Fuel Efficiency and Save Money at the Pump\"](http:\/\/car1.ca\/blog\/2016\/08\/02\/20-ways-to-improve-your-fuel-efficiency-and-save-money-at-the-pump\/). [Archived](https:\/\/web.archive.org\/web\/20160816132350\/http:\/\/car1.ca\/blog\/2016\/08\/02\/20-ways-to-improve-your-fuel-efficiency-and-save-money-at-the-pump\/) from the original on 2016-08-16.\n15. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy-efficient_driving_merriam-webster.com_15-0)** <http:\/\/www.merriam-webster.com\/dictionary\/hypermiling> Merriam Webster dictionary\n16. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-16)**\n    [\"Staying Ahead Of The Curve: 3 Key Fleet Management Trends For 2023\"](https:\/\/www.forbes.com\/councils\/forbestechcouncil\/2023\/04\/18\/staying-ahead-of-the-curve-3-key-fleet-management-trends-for-2023\/). *Forbes*. April 18, 2023. Retrieved October 7, 2025.\n17. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-17)**\n    [\"Rail 10 times better than air in London-Paris CO2 comparison - Transport & Environment\"](http:\/\/www.transportenvironment.org\/Article267.html). [Archived](https:\/\/web.archive.org\/web\/20070928024427\/http:\/\/www.transportenvironment.org\/Article267.html) from the original on 2007-09-28.\n18. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Top_Tier_Gasoline_18-0)** [Top Tier Gasoline](http:\/\/www.toptiergas.com\/retailers.html) [Archived](https:\/\/web.archive.org\/web\/20130815031514\/http:\/\/www.toptiergas.com\/retailers.html) 2013-08-15 at the [Wayback Machine](https:\/\/en.wikipedia.org\/wiki\/Wayback_Machine \"Wayback Machine\")\n19. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-19)**\n    [\"Deposit Control Standards\"](https:\/\/web.archive.org\/web\/20040806012056\/http:\/\/www.toptiergas.com\/deposit_control.html). Archived from [the original](http:\/\/www.toptiergas.com\/deposit_control.html) on 2004-08-06. Retrieved 2012-10-19.\n20. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-20)** [SOFBAL-2 experiment results](https:\/\/microgravity.grc.nasa.gov\/combustion\/lsp\/lsp1_results.htm) [Archived](https:\/\/web.archive.org\/web\/20070312020123\/http:\/\/microgravity.grc.nasa.gov\/combustion\/lsp\/lsp1_results.htm) 2007-03-12 at the [Wayback Machine](https:\/\/en.wikipedia.org\/wiki\/Wayback_Machine \"Wayback Machine\"), National Aeronautics and Space Administration, April 2005.\n\n## External links\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=13 \"Edit section: External links\")\\]\n\n|   |   |\n|---|---|\n| ![](https:\/\/upload.wikimedia.org\/wikipedia\/en\/thumb\/f\/f2\/Edit-clear.svg\/40px-Edit-clear.svg.png) | This article's **use of [external links](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:External_links \"Wikipedia:External links\") may not follow Wikipedia's policies or guidelines**. Please [improve this article](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit) by removing [excessive](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:What_Wikipedia_is_not#Wikipedia_is_not_a_mirror_or_a_repository_of_links,_images,_or_media_files \"Wikipedia:What Wikipedia is not\") or [inappropriate](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:External_links \"Wikipedia:External links\") external links, and converting useful links where appropriate into [footnote references](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citing_sources \"Wikipedia:Citing sources\"). *(November 2023)* *([Learn how and when to remove this message](https:\/\/en.wikipedia.org\/wiki\/Help:Maintenance_template_removal \"Help:Maintenance template removal\"))* |\n\n- [US Government website on fuel economy](https:\/\/www.fueleconomy.gov\/)\n- [UK DfT comparisons on road and rail](http:\/\/www.dft.gov.uk\/stellent\/groups\/dft_railways\/documents\/page\/dft_railways_611287.pdf)\n- [NASA Offers a \\$1.5 Million Prize for a Fast and Fuel-Efficient Aircraft](http:\/\/apps1.eere.energy.gov\/news\/news_detail.cfm\/news_id=12694) [Archived](https:\/\/web.archive.org\/web\/20160303200449\/http:\/\/apps1.eere.energy.gov\/news\/news_detail.cfm\/news_id=12694) 2016-03-03 at the [Wayback Machine](https:\/\/en.wikipedia.org\/wiki\/Wayback_Machine \"Wayback Machine\")\n- [Car Fuel Consumption Official Figures](http:\/\/www.carfuelconsumption.com\/)\n- [Spritmonitor.de \"the most fuel efficient cars\" - Database of thousands of (mostly German) car owners' actual fuel consumption figures](https:\/\/www.spritmonitor.de\/de\/die_sparsamsten_autos.html) (cf. [Spritmonitor](https:\/\/en.wikipedia.org\/wiki\/Spritmonitor \"Spritmonitor\"))\n- [Searchable fuel economy data from the EPA - United States Environmental Protection Agency](https:\/\/web.archive.org\/web\/20131029195658\/http:\/\/fueleconomy.carconsumption.com\/)\n- [penghemat bbm - Alat penghemat bbm](http:\/\/www.xpower-ionizer.com\/)\n- [Ny Times: A Road Test of Alternative Fuel Visions](https:\/\/www.nytimes.com\/2014\/11\/18\/science\/earth\/hydrogen-cars-join-electric-models-in-showrooms.html)\n\n| [v](https:\/\/en.wikipedia.org\/wiki\/Template:Public_infrastructure_topics \"Template:Public infrastructure topics\") [t](https:\/\/en.wikipedia.org\/wiki\/Template_talk:Public_infrastructure_topics \"Template talk:Public infrastructure topics\") [e](https:\/\/en.wikipedia.org\/wiki\/Special:EditPage\/Template:Public_infrastructure_topics \"Special:EditPage\/Template:Public infrastructure topics\")[Public infrastructure](https:\/\/en.wikipedia.org\/wiki\/Public_infrastructure \"Public infrastructure\") |   |\n|---|---|\n| [Assets](https:\/\/en.wikipedia.org\/wiki\/Fixed_asset \"Fixed asset\") and facilities | [Airports](https:\/\/en.wikipedia.org\/wiki\/Airport \"Airport\") [Bridges](https:\/\/en.wikipedia.org\/wiki\/Bridge \"Bridge\") [Broadband](https:\/\/en.wikipedia.org\/wiki\/Broadband \"Broadband\") [Canals](https:\/\/en.wikipedia.org\/wiki\/Canal \"Canal\") [Critical infrastructure](https:\/\/en.wikipedia.org\/wiki\/Critical_infrastructure \"Critical infrastructure\") [Dams](https:\/\/en.wikipedia.org\/wiki\/Dam \"Dam\") [Electricity generation](https:\/\/en.wikipedia.org\/wiki\/Electricity_generation \"Electricity generation\") [Energy development](https:\/\/en.wikipedia.org\/wiki\/Energy_development \"Energy development\") [Hazardous waste](https:\/\/en.wikipedia.org\/wiki\/Hazardous_waste \"Hazardous waste\") [Hospitals](https:\/\/en.wikipedia.org\/wiki\/Hospital \"Hospital\") [Levees](https:\/\/en.wikipedia.org\/wiki\/Levee \"Levee\") [Lighthouses](https:\/\/en.wikipedia.org\/wiki\/Lighthouse \"Lighthouse\") [Municipal solid waste](https:\/\/en.wikipedia.org\/wiki\/Municipal_solid_waste \"Municipal solid waste\") [Parks](https:\/\/en.wikipedia.org\/wiki\/Park \"Park\") [Ports](https:\/\/en.wikipedia.org\/wiki\/Port \"Port\") [Public housing](https:\/\/en.wikipedia.org\/wiki\/Public_housing \"Public housing\") [Public spaces](https:\/\/en.wikipedia.org\/wiki\/Public_space \"Public space\") [Public transport](https:\/\/en.wikipedia.org\/wiki\/Public_transport \"Public transport\") [Public utilities](https:\/\/en.wikipedia.org\/wiki\/Public_utility \"Public utility\") [Public works](https:\/\/en.wikipedia.org\/wiki\/Public_works \"Public works\") [Rail transport](https:\/\/en.wikipedia.org\/wiki\/Rail_transport \"Rail transport\") [Roads](https:\/\/en.wikipedia.org\/wiki\/Road \"Road\") [Sewage](https:\/\/en.wikipedia.org\/wiki\/Sewage \"Sewage\") [State schools](https:\/\/en.wikipedia.org\/wiki\/State_school \"State school\") [Telecommunications](https:\/\/en.wikipedia.org\/wiki\/Telecommunications \"Telecommunications\") [Town square](https:\/\/en.wikipedia.org\/wiki\/Town_square \"Town square\") [Wastewater treatment](https:\/\/en.wikipedia.org\/wiki\/Wastewater_treatment \"Wastewater treatment\") [Water supply network](https:\/\/en.wikipedia.org\/wiki\/Water_supply_network \"Water supply network\") [Wind power](https:\/\/en.wikipedia.org\/wiki\/Wind_power \"Wind power\") |\n| Concepts | [Appropriation](https:\/\/en.wikipedia.org\/wiki\/Appropriation_\$law\$ \"Appropriation (law)\") [Infrastructure asset management](https:\/\/en.wikipedia.org\/wiki\/Infrastructure_asset_management \"Infrastructure asset management\") [Build–operate–transfer](https:\/\/en.wikipedia.org\/wiki\/Build%E2%80%93operate%E2%80%93transfer \"Build–operate–transfer\") [Design–build](https:\/\/en.wikipedia.org\/wiki\/Design%E2%80%93build \"Design–build\") [Earmark](https:\/\/en.wikipedia.org\/wiki\/Earmark_\$politics\$ \"Earmark (politics)\") [Engineering contracts](https:\/\/en.wikipedia.org\/wiki\/Infrastructure#Engineering \"Infrastructure\") [Externality](https:\/\/en.wikipedia.org\/wiki\/Externality \"Externality\") [Fixed cost](https:\/\/en.wikipedia.org\/wiki\/Fixed_cost \"Fixed cost\") [Government debt](https:\/\/en.wikipedia.org\/wiki\/Government_debt \"Government debt\") [Infrastructure bond](https:\/\/en.wikipedia.org\/wiki\/Infrastructure_bond \"Infrastructure bond\") [Life-cycle assessment](https:\/\/en.wikipedia.org\/wiki\/Life-cycle_assessment \"Life-cycle assessment\") [Lindahl tax](https:\/\/en.wikipedia.org\/wiki\/Lindahl_tax \"Lindahl tax\") [Maintenance, repair, and operations](https:\/\/en.wikipedia.org\/wiki\/Maintenance,_repair,_and_operations \"Maintenance, repair, and operations\") [Natural monopoly](https:\/\/en.wikipedia.org\/wiki\/Natural_monopoly \"Natural monopoly\") [Property tax](https:\/\/en.wikipedia.org\/wiki\/Property_tax \"Property tax\") [Public capital](https:\/\/en.wikipedia.org\/wiki\/Public_capital \"Public capital\") [Public finance](https:\/\/en.wikipedia.org\/wiki\/Public_finance \"Public finance\") [Public good](https:\/\/en.wikipedia.org\/wiki\/Public_good_\$economics\$ \"Public good (economics)\") [Public sector](https:\/\/en.wikipedia.org\/wiki\/Public_sector \"Public sector\") [Public–private partnership](https:\/\/en.wikipedia.org\/wiki\/Public%E2%80%93private_partnership \"Public–private partnership\") [Renovation](https:\/\/en.wikipedia.org\/wiki\/Renovation \"Renovation\") [Spillover](https:\/\/en.wikipedia.org\/wiki\/Spillover_\$economics\$ \"Spillover (economics)\") [Supply chain](https:\/\/en.wikipedia.org\/wiki\/Supply_chain \"Supply chain\") [Taxation](https:\/\/en.wikipedia.org\/wiki\/Tax \"Tax\") [Upgrade](https:\/\/en.wikipedia.org\/wiki\/Upgrade \"Upgrade\") |\n| Issues and ideas | [Air traffic control](https:\/\/en.wikipedia.org\/wiki\/Air_traffic_control \"Air traffic control\") [Brownfield land](https:\/\/en.wikipedia.org\/wiki\/Brownfield_land \"Brownfield land\") [Bus rapid transit](https:\/\/en.wikipedia.org\/wiki\/Bus_rapid_transit \"Bus rapid transit\") [Carbon footprint](https:\/\/en.wikipedia.org\/wiki\/Carbon_footprint \"Carbon footprint\") [Congestion pricing](https:\/\/en.wikipedia.org\/wiki\/Congestion_pricing \"Congestion pricing\") [Containerization](https:\/\/en.wikipedia.org\/wiki\/Containerization \"Containerization\") [Ethanol fuel](https:\/\/en.wikipedia.org\/wiki\/Ethanol_fuel \"Ethanol fuel\") [Fuel efficiency]() [Fuel tax](https:\/\/en.wikipedia.org\/wiki\/Fuel_tax \"Fuel tax\") [Groundwater](https:\/\/en.wikipedia.org\/wiki\/Groundwater \"Groundwater\") [High-speed rail](https:\/\/en.wikipedia.org\/wiki\/High-speed_rail \"High-speed rail\") [Hybrid vehicles](https:\/\/en.wikipedia.org\/wiki\/Hybrid_vehicle \"Hybrid vehicle\") [Land-use planning](https:\/\/en.wikipedia.org\/wiki\/Land-use_planning \"Land-use planning\") [Mobile data terminal](https:\/\/en.wikipedia.org\/wiki\/Mobile_data_terminal \"Mobile data terminal\") [Pork barrel](https:\/\/en.wikipedia.org\/wiki\/Pork_barrel \"Pork barrel\") [Recycling](https:\/\/en.wikipedia.org\/wiki\/Recycling \"Recycling\") [Renewable resources](https:\/\/en.wikipedia.org\/wiki\/Renewable_resource \"Renewable resource\") [Reverse osmosis](https:\/\/en.wikipedia.org\/wiki\/Reverse_osmosis \"Reverse osmosis\") [Smart grid](https:\/\/en.wikipedia.org\/wiki\/Smart_grid \"Smart grid\") [Smart growth](https:\/\/en.wikipedia.org\/wiki\/Smart_growth \"Smart growth\") [Stormwater](https:\/\/en.wikipedia.org\/wiki\/Stormwater \"Stormwater\") [Sustainable urban infrastructure](https:\/\/en.wikipedia.org\/wiki\/Sustainable_urban_infrastructure \"Sustainable urban infrastructure\") [Traffic congestion](https:\/\/en.wikipedia.org\/wiki\/Traffic_congestion \"Traffic congestion\") [Transit-oriented development](https:\/\/en.wikipedia.org\/wiki\/Transit-oriented_development \"Transit-oriented development\") [Urban sprawl](https:\/\/en.wikipedia.org\/wiki\/Urban_sprawl \"Urban sprawl\") [Waste-to-energy](https:\/\/en.wikipedia.org\/wiki\/Waste-to-energy \"Waste-to-energy\") [Weatherization](https:\/\/en.wikipedia.org\/wiki\/Weatherization \"Weatherization\") [Wireless](https:\/\/en.wikipedia.org\/wiki\/Wireless \"Wireless\") |\n| Fields of study | [Architecture](https:\/\/en.wikipedia.org\/wiki\/Architecture \"Architecture\") [Civil engineering](https:\/\/en.wikipedia.org\/wiki\/Civil_engineering \"Civil engineering\") [Electrical engineering](https:\/\/en.wikipedia.org\/wiki\/Electrical_engineering \"Electrical engineering\") [Mechanical engineering](https:\/\/en.wikipedia.org\/wiki\/Mechanical_engineering \"Mechanical engineering\") [Public economics](https:\/\/en.wikipedia.org\/wiki\/Public_economics \"Public economics\") [Public policy](https:\/\/en.wikipedia.org\/wiki\/Public_policy \"Public policy\") [Urban planning](https:\/\/en.wikipedia.org\/wiki\/Urban_planning \"Urban planning\") |\n| Examples | [Akashi Kaikyō Bridge](https:\/\/en.wikipedia.org\/wiki\/Akashi_Kaiky%C5%8D_Bridge \"Akashi Kaikyō Bridge\") [Autobahn](https:\/\/en.wikipedia.org\/wiki\/Autobahn \"Autobahn\") [Brooklyn Bridge](https:\/\/en.wikipedia.org\/wiki\/Brooklyn_Bridge \"Brooklyn Bridge\") [Bus rapid transit systems](https:\/\/en.wikipedia.org\/wiki\/List_of_bus_rapid_transit_systems \"List of bus rapid transit systems\") [Channel Tunnel](https:\/\/en.wikipedia.org\/wiki\/Channel_Tunnel \"Channel Tunnel\") [Controlled-access highway systems](https:\/\/en.wikipedia.org\/wiki\/List_of_controlled-access_highway_systems \"List of controlled-access highway systems\") [Electric power transmission](https:\/\/en.wikipedia.org\/wiki\/Electric_power_transmission#Overhead_transmission \"Electric power transmission\") [High-speed trains](https:\/\/en.wikipedia.org\/wiki\/List_of_high-speed_trains \"List of high-speed trains\") [Hong Kong International Airport](https:\/\/en.wikipedia.org\/wiki\/Hong_Kong_International_Airport \"Hong Kong International Airport\") [Hoover Dam](https:\/\/en.wikipedia.org\/wiki\/Hoover_Dam \"Hoover Dam\") [Humber Bridge](https:\/\/en.wikipedia.org\/wiki\/Humber_Bridge \"Humber Bridge\") [Kansai International Airport](https:\/\/en.wikipedia.org\/wiki\/Kansai_International_Airport \"Kansai International Airport\") [Millau Viaduct](https:\/\/en.wikipedia.org\/wiki\/Millau_Viaduct \"Millau Viaduct\") [Nuclear power](https:\/\/en.wikipedia.org\/wiki\/Nuclear_power_by_country \"Nuclear power by country\") [Offshore wind farms](https:\/\/en.wikipedia.org\/wiki\/List_of_offshore_wind_farms \"List of offshore wind farms\") [Panama Canal](https:\/\/en.wikipedia.org\/wiki\/Panama_Canal \"Panama Canal\") [Port of Shanghai](https:\/\/en.wikipedia.org\/wiki\/Port_of_Shanghai \"Port of Shanghai\") [San Francisco–Oakland Bay Bridge](https:\/\/en.wikipedia.org\/wiki\/San_Francisco%E2%80%93Oakland_Bay_Bridge \"San Francisco–Oakland Bay Bridge\") [Suez Canal](https:\/\/en.wikipedia.org\/wiki\/Suez_Canal \"Suez Canal\") [Solar power](https:\/\/en.wikipedia.org\/wiki\/Solar_power_by_country \"Solar power by country\") [Three Gorges Dam](https:\/\/en.wikipedia.org\/wiki\/Three_Gorges_Dam \"Three Gorges Dam\") [Trans-Alaska pipeline](https:\/\/en.wikipedia.org\/wiki\/Trans-Alaska_Pipeline_System \"Trans-Alaska Pipeline System\") [Transcontinental railroads](https:\/\/en.wikipedia.org\/wiki\/Transcontinental_railroad \"Transcontinental railroad\") |\n\n![](https:\/\/en.wikipedia.org\/wiki\/Special:CentralAutoLogin\/start?useformat=desktop&type=1x1&usesul3=1)\n\nRetrieved from \"<https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&oldid=1317110748>\"\n\n[Categories](https:\/\/en.wikipedia.org\/wiki\/Help:Category \"Help:Category\"):\n\n- [Energy 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Wikipedia® is a registered trademark of the [Wikimedia Foundation, Inc.](https:\/\/wikimediafoundation.org\/), a non-profit organization.\n\n- [Privacy policy](https:\/\/foundation.wikimedia.org\/wiki\/Special:MyLanguage\/Policy:Privacy_policy)\n- [About Wikipedia](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:About)\n- [Disclaimers](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:General_disclaimer)\n- [Contact Wikipedia](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Contact_us)\n- [Legal & safety contacts](https:\/\/foundation.wikimedia.org\/wiki\/Special:MyLanguage\/Legal:Wikimedia_Foundation_Legal_and_Safety_Contact_Information)\n- [Code of Conduct](https:\/\/foundation.wikimedia.org\/wiki\/Special:MyLanguage\/Policy:Universal_Code_of_Conduct)\n- [Developers](https:\/\/developer.wikimedia.org\/)\n- [Statistics](https:\/\/stats.wikimedia.org\/#\/en.wikipedia.org)\n- [Cookie statement](https:\/\/foundation.wikimedia.org\/wiki\/Special:MyLanguage\/Policy:Cookie_statement)\n- [Mobile view](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&mobileaction=toggle_view_mobile)\n\n- [![Wikimedia Foundation](https:\/\/en.wikipedia.org\/static\/images\/footer\/wikimedia.svg)](https:\/\/www.wikimedia.org\/)\n- [![Powered by MediaWiki](https:\/\/en.wikipedia.org\/w\/resources\/assets\/mediawiki_compact.svg)](https:\/\/www.mediawiki.org\/)\n\nSearch\n\nToggle the table of contents\n\nFuel efficiency\n\n8 languages\n\n[Add topic](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency)","attrs_readable_markdown":"From Wikipedia, the free encyclopedia\n\n**Fuel efficiency** (or **fuel economy**) is a form of [thermal efficiency](https:\/\/en.wikipedia.org\/wiki\/Thermal_efficiency \"Thermal efficiency\"), meaning the [ratio](https:\/\/en.wikipedia.org\/wiki\/Ratio \"Ratio\") of effort to result of a process that converts [chemical](https:\/\/en.wikipedia.org\/wiki\/Chemical_energy \"Chemical energy\") [potential energy](https:\/\/en.wikipedia.org\/wiki\/Potential_energy \"Potential energy\") contained in a carrier ([fuel](https:\/\/en.wikipedia.org\/wiki\/Fuel \"Fuel\")) into kinetic energy or [work](https:\/\/en.wikipedia.org\/wiki\/Mechanical_work \"Mechanical work\"). Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous [energy profile](https:\/\/en.wikipedia.org\/wiki\/Energy_profile \"Energy profile\"). Non-transportation applications, such as [industry](https:\/\/en.wikipedia.org\/wiki\/Industrial_sector \"Industrial sector\"), benefit from increased fuel efficiency, especially [fossil fuel power plants](https:\/\/en.wikipedia.org\/wiki\/Fossil_fuel_power_plant \"Fossil fuel power plant\") or industries dealing with [combustion](https:\/\/en.wikipedia.org\/wiki\/Combustion \"Combustion\"), such as [ammonia](https:\/\/en.wikipedia.org\/wiki\/Ammonia \"Ammonia\") production during the [Haber process](https:\/\/en.wikipedia.org\/wiki\/Haber_process \"Haber process\").\n\nIn the context of [transport](https:\/\/en.wikipedia.org\/wiki\/Transport \"Transport\"), fuel economy is the [energy efficiency](https:\/\/en.wikipedia.org\/wiki\/Energy_efficiency_in_transportation \"Energy efficiency in transportation\") of a particular vehicle, given as a [ratio](https:\/\/en.wikipedia.org\/wiki\/Ratio \"Ratio\") of distance traveled per unit of [fuel](https:\/\/en.wikipedia.org\/wiki\/Motor_fuel \"Motor fuel\") consumed. It is dependent on several factors including [engine efficiency](https:\/\/en.wikipedia.org\/wiki\/Engine_efficiency \"Engine efficiency\"), [transmission](https:\/\/en.wikipedia.org\/wiki\/Transmission_\$mechanics\$ \"Transmission (mechanics)\") design, and [tire](https:\/\/en.wikipedia.org\/wiki\/Tire \"Tire\") design. In most countries, using the [metric system](https:\/\/en.wikipedia.org\/wiki\/Metric_system \"Metric system\"), fuel economy is stated as \"fuel consumption\" in [liters](https:\/\/en.wikipedia.org\/wiki\/Liter \"Liter\") per 100 [kilometers](https:\/\/en.wikipedia.org\/wiki\/Kilometers \"Kilometers\") (L\/100 km) or kilometers per liter (km\/L or kmpl). In a number of countries still using other systems, fuel economy is expressed in [miles](https:\/\/en.wikipedia.org\/wiki\/Mile \"Mile\") per [gallon](https:\/\/en.wikipedia.org\/wiki\/Gallon \"Gallon\") (mpg), for example in the US and usually also in the UK ([imperial](https:\/\/en.wikipedia.org\/wiki\/Imperial_units \"Imperial units\") gallon); there is sometimes confusion as the imperial gallon is 20% larger than the US gallon so that mpg values are not directly comparable. Traditionally, litres per [mil](https:\/\/en.wikipedia.org\/wiki\/Scandinavian_mile \"Scandinavian mile\") were used in [Norway](https:\/\/en.wikipedia.org\/wiki\/Norway \"Norway\") and [Sweden](https:\/\/en.wikipedia.org\/wiki\/Sweden \"Sweden\"), but both have aligned to the EU standard of L\/100 km.[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-1)\n\nFuel consumption is a more accurate measure of a vehicle's performance because it is a linear relationship while fuel economy leads to distortions in efficiency improvements.[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-2) Weight-specific efficiency (efficiency per unit weight) may be stated for [freight](https:\/\/en.wikipedia.org\/wiki\/Freight \"Freight\"), and passenger-specific efficiency (vehicle efficiency per passenger) for passenger vehicles.\n\nFuel efficiency is dependent on many parameters of a vehicle, including its [engine](https:\/\/en.wikipedia.org\/wiki\/Engine \"Engine\") parameters, [aerodynamic drag](https:\/\/en.wikipedia.org\/wiki\/Drag_\$physics\$ \"Drag (physics)\"), weight, AC usage, fuel and [rolling resistance](https:\/\/en.wikipedia.org\/wiki\/Rolling_resistance \"Rolling resistance\"). There have been advances in all areas of vehicle design in recent decades. Fuel efficiency of vehicles can also be improved by careful maintenance and driving habits.[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-3)\n\n[Hybrid vehicles](https:\/\/en.wikipedia.org\/wiki\/Hybrid_vehicles \"Hybrid vehicles\") use two or more power sources for propulsion. In many designs, a small combustion engine is combined with electric motors. Kinetic energy which would otherwise be lost to heat during braking is recaptured as electrical power to improve fuel efficiency. The larger batteries in these vehicles power the [car's electronics](https:\/\/en.wikipedia.org\/wiki\/Automotive_electronics \"Automotive electronics\"), allowing the engine to shut off and avoid prolonged [idling](https:\/\/en.wikipedia.org\/wiki\/Start-stop_system \"Start-stop system\").[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-4)\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/9\/90\/1975-_US_vehicle_production_share%2C_by_vehicle_type.svg\/250px-1975-_US_vehicle_production_share%2C_by_vehicle_type.svg.png)](https:\/\/en.wikipedia.org\/wiki\/File:1975-_US_vehicle_production_share,_by_vehicle_type.svg)\n\nTrucks' share of US vehicles produced, has tripled since 1975. Though vehicle fuel efficiency has increased within each category, the overall trend toward less efficient types of vehicles has offset some of the benefits of greater fuel economy and reduction in carbon dioxide emissions.[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-EPA_AutomotiveTrends_202212-5) Without the shift towards SUVs, energy use per unit distance could have fallen 30% more than it did from 2010 to 2022.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-GlobalFuelEfficInit_202311-6)\n\nFleet efficiency describes the average efficiency of a population of vehicles. Technological advances in efficiency may be offset by a change in buying habits with a propensity to heavier vehicles that are less fuel-efficient.[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-EPA_AutomotiveTrends_202212-5)\n\n## Energy efficiency terminology\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=3 \"Edit section: Energy efficiency terminology\")\\]\n\n[Energy efficiency](https:\/\/en.wikipedia.org\/wiki\/Energy_efficiency_\$physics\$ \"Energy efficiency (physics)\") is similar to fuel efficiency but the input is usually in units of energy such as [megajoules](https:\/\/en.wikipedia.org\/wiki\/Megajoules \"Megajoules\") (MJ), [kilowatt-hours](https:\/\/en.wikipedia.org\/wiki\/Kilowatt-hours \"Kilowatt-hours\") (kW·h), kilocalories (kcal) or [British thermal units](https:\/\/en.wikipedia.org\/wiki\/British_thermal_units \"British thermal units\") (BTU). The inverse of \"energy efficiency\" is \"[energy intensity](https:\/\/en.wikipedia.org\/wiki\/Energy_intensity \"Energy intensity\")\", or the amount of input energy required for a unit of output such as MJ\/passenger-km (of passenger transport), BTU\/ton-mile or kJ\/t-km (of freight transport), GJ\/t (for production of steel and other materials), BTU\/(kW·h) (for electricity generation), or litres\/100 km (of vehicle travel). Litres per 100 km is also a measure of \"energy intensity\" where the input is measured by the amount of fuel and the output is measured by the [distance](https:\/\/en.wikipedia.org\/wiki\/Distance \"Distance\") travelled. For example: [Fuel economy in automobiles](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy_in_automobiles \"Fuel economy in automobiles\").\n\nGiven a heat value of a fuel, it would be trivial to convert from fuel units (such as litres of gasoline) to energy units (such as MJ) and conversely. But there are two problems with comparisons made using energy units:\n\n- There are two different heat values for any hydrogen-containing fuel which can differ by several percent (see below).\n- When comparing transportation energy costs, a [kilowatt hour](https:\/\/en.wikipedia.org\/wiki\/Kilowatt_hour \"Kilowatt hour\") of electric energy may require an amount of fuel with heating value of 2 or 3 kilowatt hours to produce it.\n\n## Energy content of fuel\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=4 \"Edit section: Energy content of fuel\")\\]\n\nThe specific [energy content](https:\/\/en.wikipedia.org\/wiki\/Energy_content \"Energy content\") of a fuel is the heat energy obtained when a certain quantity is burned (such as a gallon, litre, kilogram). It is sometimes called the [heat of combustion](https:\/\/en.wikipedia.org\/wiki\/Heat_of_combustion \"Heat of combustion\"). There exists two different values of [specific heat](https:\/\/en.wikipedia.org\/wiki\/Specific_heat \"Specific heat\") energy for the same batch of fuel. One is the high (or gross) heat of combustion and the other is the low (or net) heat of combustion. The high value is obtained when, after the combustion, the water in the exhaust is in liquid form. For the low value, the exhaust has all the water in vapor form (steam). Since water vapor gives up heat energy when it changes from vapor to liquid, the liquid water value is larger since it includes the [latent heat](https:\/\/en.wikipedia.org\/wiki\/Latent_heat \"Latent heat\") of vaporization of water. The difference between the high and low values is significant, about 8 or 9%. This accounts for most of the apparent discrepancy in the heat value of gasoline. In the U.S. (and the table) the high heat values have traditionally been used, but in many other countries, the low heat values are commonly used.\n\n| Fuel type | MJ\/L | MJ\/kg | [BTU](https:\/\/en.wikipedia.org\/wiki\/British_thermal_unit \"British thermal unit\")\/[imp gal](https:\/\/en.wikipedia.org\/wiki\/Gallon \"Gallon\") | BTU\/[US gal](https:\/\/en.wikipedia.org\/wiki\/US_gallon \"US gallon\") | [Research octane  number (RON)](https:\/\/en.wikipedia.org\/wiki\/Octane_rating \"Octane rating\") |\n|---|---|---|---|---|---|\n| Regular [gasoline](https:\/\/en.wikipedia.org\/wiki\/Gasoline \"Gasoline\")\/petrol | 34\\.8 | ~47 | 150,100 | 125,000 | Min. 91 |\n| Premium [gasoline](https:\/\/en.wikipedia.org\/wiki\/Gasoline \"Gasoline\")\/petrol |   | ~46 |   |   | Min. 95 |\n| [Autogas](https:\/\/en.wikipedia.org\/wiki\/Autogas \"Autogas\") ([LPG](https:\/\/en.wikipedia.org\/wiki\/Liquefied_petroleum_gas \"Liquefied petroleum gas\")) (60% [propane](https:\/\/en.wikipedia.org\/wiki\/Propane \"Propane\") and 40% [butane](https:\/\/en.wikipedia.org\/wiki\/Butane \"Butane\")) | 25\\.5–28.7 | ~51 |   |   | 108–110 |\n| [Ethanol](https:\/\/en.wikipedia.org\/wiki\/Ethanol_fuel \"Ethanol fuel\") | 23\\.5 | 31\\.1[\\[7\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-7) | 101,600 | 84,600 | 129 |\n| [Methanol](https:\/\/en.wikipedia.org\/wiki\/Methanol \"Methanol\") | 17\\.9 | 19\\.9 | 77,600 | 64,600 | 123 |\n| [Gasohol](https:\/\/en.wikipedia.org\/wiki\/Alcohol_fuel \"Alcohol fuel\") (10% ethanol and 90% gasoline) | 33\\.7 | ~45 | 145,200 | 121,000 | 93\/94 |\n| [E85](https:\/\/en.wikipedia.org\/wiki\/E85 \"E85\") (85% ethanol and 15% gasoline) | 25\\.2 | ~33 | 108,878 | 90,660 | 100–105 |\n| [Diesel](https:\/\/en.wikipedia.org\/wiki\/Diesel_fuel \"Diesel fuel\") | 38\\.6 | ~48 | 166,600 | 138,700 | [N\/A (see cetane)](https:\/\/en.wikipedia.org\/wiki\/Cetane_number \"Cetane number\") |\n| [Biodiesel](https:\/\/en.wikipedia.org\/wiki\/Biodiesel \"Biodiesel\") | 35\\.1 | 39\\.9 | 151,600 | 126,200 | [N\/A (see cetane)](https:\/\/en.wikipedia.org\/wiki\/Cetane_number \"Cetane number\") |\n| [Vegetable oil](https:\/\/en.wikipedia.org\/wiki\/WVO \"WVO\") (using 9.00 kcal\/g) | 34\\.3 | 37\\.7 | 147,894 | 123,143 |   |\n| [Aviation gasoline](https:\/\/en.wikipedia.org\/wiki\/Aviation_gasoline \"Aviation gasoline\") | 33\\.5 | 46\\.8 | 144,400 | 120,200 | 80-145 |\n| [Jet fuel](https:\/\/en.wikipedia.org\/wiki\/Jet_fuel \"Jet fuel\"), naphtha | 35\\.5 | 46\\.6 | 153,100 | 127,500 | N\/A to turbine engines |\n| [Jet fuel](https:\/\/en.wikipedia.org\/wiki\/Jet_fuel \"Jet fuel\"), kerosene | 37\\.6 | ~47 | 162,100 | 135,000 | N\/A to turbine engines |\n| [Liquefied natural gas](https:\/\/en.wikipedia.org\/wiki\/Liquefied_natural_gas \"Liquefied natural gas\") | 25\\.3 | ~55 | 109,000 | 90,800 |   |\n| [Liquid hydrogen](https:\/\/en.wikipedia.org\/wiki\/Liquid_hydrogen \"Liquid hydrogen\") | 9\\.3 | ~130 | 40,467 | 33,696 |   |\n\n[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-TEDB-8)\n\nNeither the gross heat of combustion nor the net heat of combustion gives the theoretical amount of mechanical energy (work) that can be obtained from the reaction. (This is given by the change in [Gibbs free energy](https:\/\/en.wikipedia.org\/wiki\/Gibbs_free_energy \"Gibbs free energy\"), and is around 45.7 MJ\/kg for gasoline.) The actual amount of mechanical work obtained from fuel (the inverse of the [specific fuel consumption](https:\/\/en.wikipedia.org\/wiki\/Brake-specific_fuel_consumption \"Brake-specific fuel consumption\")) depends on the engine. A figure of 17.6 MJ\/kg is possible with a gasoline engine, and 19.1 MJ\/kg for a diesel engine. See [Brake-specific fuel consumption](https:\/\/en.wikipedia.org\/wiki\/Brake-specific_fuel_consumption \"Brake-specific fuel consumption\") for more information.\\[*[clarification needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Please_clarify \"Wikipedia:Please clarify\")*\\]\n\nThe [energy efficiency in transport](https:\/\/en.wikipedia.org\/wiki\/Energy_efficiency_in_transport \"Energy efficiency in transport\") is the useful travelled [distance](https:\/\/en.wikipedia.org\/wiki\/Distance \"Distance\"), of passengers, goods or any type of load; divided by the total [energy](https:\/\/en.wikipedia.org\/wiki\/Energy \"Energy\") put into the transport [propulsion](https:\/\/en.wikipedia.org\/wiki\/Propulsion \"Propulsion\") means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in [liquid fuels](https:\/\/en.wikipedia.org\/wiki\/Liquid_fuel \"Liquid fuel\"), [electrical energy](https:\/\/en.wikipedia.org\/wiki\/Electrical_energy \"Electrical energy\") or [food energy](https:\/\/en.wikipedia.org\/wiki\/Food_energy \"Food energy\").[\\[9\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-9)[\\[10\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_fueleco-10) The [energy efficiency](https:\/\/en.wikipedia.org\/wiki\/Efficient_energy_use \"Efficient energy use\") is also occasionally known as [energy intensity](https:\/\/en.wikipedia.org\/wiki\/Energy_intensity \"Energy intensity\").[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_DOEgloss-11) The [inverse](https:\/\/en.wikipedia.org\/wiki\/Multiplicative_inverse \"Multiplicative inverse\") of the energy efficiency in transport is the energy consumption in transport.\n\nEnergy efficiency in transport is often described in terms of [fuel consumption](https:\/\/en.wikipedia.org\/wiki\/Fuel_consumption \"Fuel consumption\"), fuel consumption being the reciprocal of fuel economy.[\\[10\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_fueleco-10) Nonetheless, fuel consumption is linked with a means of propulsion which uses [liquid fuels](https:\/\/en.wikipedia.org\/wiki\/Liquid_fuel \"Liquid fuel\"), whilst energy efficiency is applicable to any sort of propulsion. To avoid said confusion, and to be able to compare the energy efficiency in any type of vehicle, experts tend to measure the energy in the [International System of Units](https:\/\/en.wikipedia.org\/wiki\/International_System_of_Units \"International System of Units\"), i.e., [joules](https:\/\/en.wikipedia.org\/wiki\/Joule \"Joule\").\n\nTherefore, in the International System of Units, the energy efficiency in transport is measured in terms of metre per joule, or m\/J, while the energy consumption in transport is measured in terms of joules per metre, or J\/m. The more efficient the vehicle, the more metres it covers with one joule (more efficiency), or the fewer joules it uses to travel over one metre (less consumption). The [energy efficiency](https:\/\/en.wikipedia.org\/wiki\/Efficient_energy_use \"Efficient energy use\") in transport largely varies by means of transport. Different types of [transport](https:\/\/en.wikipedia.org\/wiki\/Transportation \"Transportation\") range from some hundred [kilojoules](https:\/\/en.wikipedia.org\/wiki\/Joule \"Joule\") per kilometre (kJ\/km) for a [bicycle](https:\/\/en.wikipedia.org\/wiki\/Bicycle \"Bicycle\") to tens of megajoules per kilometre (MJ\/km) for a [helicopter](https:\/\/en.wikipedia.org\/wiki\/Helicopter \"Helicopter\").\n\nVia type of fuel used and rate of fuel consumption, energy efficiency is also often related to operating cost (\\$\/km) and environmental emissions (e.g. CO2\/km).\n\n### Fuel efficiency of motor vehicles\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=6 \"Edit section: Fuel efficiency of motor vehicles\")\\]\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/3\/38\/CAFE_performance.svg\/250px-CAFE_performance.svg.png)](https:\/\/en.wikipedia.org\/wiki\/File:CAFE_performance.svg)\n\nNew light-duty vehicle fuel economy by vehicle type from vehicle manufacturers in the United States, in miles per gallon (1975 - 2019)\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/3\/35\/2006_Honda_Airwave_fuel_efficiency_meter.jpg\/250px-2006_Honda_Airwave_fuel_efficiency_meter.jpg)](https:\/\/en.wikipedia.org\/wiki\/File:2006_Honda_Airwave_fuel_efficiency_meter.jpg)\n\nFuel consumption monitor from a 2006 [Honda Airwave](https:\/\/en.wikipedia.org\/wiki\/Honda_Airwave \"Honda Airwave\"). The displayed fuel economy is 18.1 km\/L (5.5 L\/100 km; 43 mpg‑US).\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/0\/02\/Fuel_Economy%2C_1916.jpg\/250px-Fuel_Economy%2C_1916.jpg)](https:\/\/en.wikipedia.org\/wiki\/File:Fuel_Economy,_1916.jpg)\n\nA [Briggs and Stratton Flyer](https:\/\/en.wikipedia.org\/wiki\/Briggs_and_Stratton_Flyer \"Briggs and Stratton Flyer\") from 1916. Originally an experiment in creating a fuel-saving automobile in the United States, the vehicle weighed only 135 lb (61.2 kg) and was an adaptation of a small gasoline engine originally designed to power a bicycle.[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-12)\n\nThe [fuel economy](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy_in_automobiles \"Fuel economy in automobiles\") or fuel efficiency of an [automobile](https:\/\/en.wikipedia.org\/wiki\/Car \"Car\") relates to the [distance traveled](https:\/\/en.wikipedia.org\/wiki\/Distance_traveled \"Distance traveled\") by a vehicle and the amount of [fuel](https:\/\/en.wikipedia.org\/wiki\/Fuel \"Fuel\") consumed. It can be expressed in terms of the volume of fuel to travel a given distance, such as in litres per 100 kilometres (L\/100 km), or through its inverse, the distance traveled per unit volume of fuel consumed, as in kilometres per litre (km\/L) or miles per gallon (mpg). Since fuel economy of vehicles is a significant factor in [air pollution](https:\/\/en.wikipedia.org\/wiki\/Air_pollution \"Air pollution\"), the importation of [motor fuel](https:\/\/en.wikipedia.org\/wiki\/Motor_fuel \"Motor fuel\") can be a large part of a nation's [foreign trade](https:\/\/en.wikipedia.org\/wiki\/Foreign_trade \"Foreign trade\") and consumers frequently undervalue fuel efficiency, many countries impose requirements for fuel economy.\n\nDifferent methods are used to approximate the actual performance of the vehicle. The energy in fuel is required to overcome various losses ([wind resistance](https:\/\/en.wikipedia.org\/wiki\/Wind_resistance \"Wind resistance\"), [tire drag](https:\/\/en.wikipedia.org\/wiki\/Tire_drag \"Tire drag\"), and others) encountered while propelling the vehicle, and in providing power to vehicle systems such as ignition or air conditioning. Various strategies can be employed to reduce losses at each of the conversions between the [chemical energy](https:\/\/en.wikipedia.org\/wiki\/Chemical_energy \"Chemical energy\") in the fuel and the [kinetic energy](https:\/\/en.wikipedia.org\/wiki\/Kinetic_energy \"Kinetic energy\") of the vehicle. Driver behavior can affect fuel economy; maneuvers such as sudden acceleration and heavy [braking](https:\/\/en.wikipedia.org\/wiki\/Braking \"Braking\") waste energy.\n\n[Electric cars](https:\/\/en.wikipedia.org\/wiki\/Electric_car \"Electric car\") use [kilowatt-hours](https:\/\/en.wikipedia.org\/wiki\/Kilowatt-hours \"Kilowatt-hours\") of electricity per 100 kilometres (kWh\/100km); in the U.S., an equivalence measure, such as [miles per gallon gasoline equivalent](https:\/\/en.wikipedia.org\/wiki\/Miles_per_gallon_gasoline_equivalent \"Miles per gallon gasoline equivalent\") (US gallon) has been created to attempt to compare them.\n\n[Energy-efficient driving](https:\/\/en.wikipedia.org\/wiki\/Energy-efficient_driving \"Energy-efficient driving\") techniques are used by drivers who wish to reduce their fuel consumption, and thus maximize fuel efficiency. Many drivers have the potential to improve their fuel efficiency significantly.[\\[13\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy-efficient_driving_Beusen-13) Simple things such as keeping tires properly inflated, having a vehicle well-maintained and avoiding idling can dramatically improve fuel efficiency.[\\[14\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-14) Careful use of acceleration and deceleration and especially limiting use of high speeds helps efficiency. The use of multiple such techniques is called \"[hypermiling](https:\/\/en.wikipedia.org\/wiki\/Hypermiling \"Hypermiling\")\".[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy-efficient_driving_merriam-webster.com-15)\n\nWhile these techniques can be applied by any driver, energy-efficient driving (often called \"eco-driving\") has become a major focus of modern [fleet management](https:\/\/en.wikipedia.org\/wiki\/Fleet_management \"Fleet management\"). As a key part of [fleet digitalization](https:\/\/en.wikipedia.org\/wiki\/Fleet_digitalization \"Fleet digitalization\"), companies use [telematics](https:\/\/en.wikipedia.org\/wiki\/Telematics \"Telematics\") to automatically monitor and manage fuel economy. A [fleet telematics system](https:\/\/en.wikipedia.org\/wiki\/Fleet_telematics_system \"Fleet telematics system\") collects data on behaviors that waste fuel, such as harsh acceleration, speeding, and idling. This information is then used in [driver scoring](https:\/\/en.wikipedia.org\/wiki\/Driver_scoring \"Driver scoring\") applications to identify and coach drivers.[\\[13\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Energy-efficient_driving_Beusen-13) This is often combined with dedicated [fuel-management systems](https:\/\/en.wikipedia.org\/wiki\/Fuel-management_systems \"Fuel-management systems\") that use high-precision [fuel level sensors](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_level_sensor&action=edit&redlink=1 \"Fuel level sensor (page does not exist)\") to get exact fuel consumption data and prevent [gasoline theft](https:\/\/en.wikipedia.org\/wiki\/Gasoline_theft \"Gasoline theft\").[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-16)\n\nSimple fuel-efficiency techniques can result in reduction in fuel consumption without resorting to radical fuel-saving techniques that can be unlawful and dangerous, such as tailgating larger vehicles.\n\n## Advanced technology\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=8 \"Edit section: Advanced technology\")\\]\n\nThe most efficient machines for converting energy to rotary motion are electric motors, as used in [electric vehicles](https:\/\/en.wikipedia.org\/wiki\/Electric_vehicles \"Electric vehicles\"). However, electricity is not a primary energy source so the efficiency of the electricity production has also to be taken into account. [Railway](https:\/\/en.wikipedia.org\/wiki\/Railway \"Railway\") trains can be powered using electricity, delivered through an additional running rail, overhead [catenary](https:\/\/en.wikipedia.org\/wiki\/Overhead_lines \"Overhead lines\") system or by on-board generators used in [diesel-electric](https:\/\/en.wikipedia.org\/wiki\/Diesel-electric_transmission \"Diesel-electric transmission\") locomotives as common on the US and UK rail networks. Pollution produced from centralised generation of electricity is emitted at a distant power station, rather than \"on site\". Pollution can be reduced by using more railway electrification and [low carbon power](https:\/\/en.wikipedia.org\/wiki\/Low_carbon_power \"Low carbon power\") for electricity. Some railways, such as the French SNCF and Swiss federal railways derive most, if not 100% of their power, from hydroelectric or nuclear power stations, therefore atmospheric pollution from their rail networks is very low. This was reflected in a study by AEA Technology between a [Eurostar](https:\/\/en.wikipedia.org\/wiki\/Eurostar \"Eurostar\") train and airline journeys between London and Paris, which showed the trains on average emitting 10 times less CO2, per passenger, than planes, helped in part by French nuclear generation.[\\[17\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-17)\n\n### Hydrogen fuel cells\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Fuel_efficiency&action=edit&section=9 \"Edit section: Hydrogen fuel cells\")\\]\n\nIn the future, [hydrogen cars](https:\/\/en.wikipedia.org\/wiki\/Hydrogen_vehicle \"Hydrogen vehicle\") may be commercially available. Toyota is test-marketing vehicles powered by hydrogen fuel cells in southern California, where a series of hydrogen fueling stations has been established. Powered either through chemical reactions in a [fuel cell](https:\/\/en.wikipedia.org\/wiki\/Fuel_cell \"Fuel cell\") that create electricity to drive very efficient electrical motors or by directly burning hydrogen in a combustion engine (near identically to a [natural gas vehicle](https:\/\/en.wikipedia.org\/wiki\/Natural_gas_vehicle \"Natural gas vehicle\"), and similarly compatible with both natural gas and gasoline); these vehicles promise to have near-zero pollution from the tailpipe (exhaust pipe). Potentially the atmospheric pollution could be minimal, provided the hydrogen is made by [electrolysis](https:\/\/en.wikipedia.org\/wiki\/Electrolysis \"Electrolysis\") using electricity from non-polluting sources such as solar, wind or [hydroelectricity](https:\/\/en.wikipedia.org\/wiki\/Hydroelectricity \"Hydroelectricity\") or nuclear. Commercial [hydrogen production](https:\/\/en.wikipedia.org\/wiki\/Hydrogen_production \"Hydrogen production\") uses fossil fuels and produces more carbon dioxide than hydrogen.\n\nBecause there are pollutants involved in the manufacture and destruction of a car and the production, transmission and storage of electricity and hydrogen, the label \"zero pollution\" applies only to the car's conversion of stored energy into movement.\n\nIn 2004, a consortium of major auto-makers — [BMW](https:\/\/en.wikipedia.org\/wiki\/BMW \"BMW\"), [General Motors](https:\/\/en.wikipedia.org\/wiki\/General_Motors \"General Motors\"), [Honda](https:\/\/en.wikipedia.org\/wiki\/Honda \"Honda\"), [Toyota](https:\/\/en.wikipedia.org\/wiki\/Toyota \"Toyota\") and [Volkswagen](https:\/\/en.wikipedia.org\/wiki\/Volkswagen \"Volkswagen\")\/[Audi](https:\/\/en.wikipedia.org\/wiki\/Audi \"Audi\") — came up with *\"Top Tier Detergent Gasoline Standard\"* to [gasoline](https:\/\/en.wikipedia.org\/wiki\/Gasoline \"Gasoline\") brands in the US and Canada that meet their minimum standards for [detergent](https:\/\/en.wikipedia.org\/wiki\/Detergent \"Detergent\") content[\\[18\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-Top_Tier_Gasoline-18) and do not contain metallic additives. Top Tier gasoline contains higher levels of detergent additives in order to prevent the build-up of deposits (typically, on [fuel injector](https:\/\/en.wikipedia.org\/wiki\/Fuel_injector \"Fuel injector\") and [intake valve](https:\/\/en.wikipedia.org\/wiki\/Intake_valve \"Intake valve\")) known to reduce fuel economy and engine performance.[\\[19\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-19)\n\nHow fuel combusts affects how much energy is produced. The [National Aeronautics and Space Administration](https:\/\/en.wikipedia.org\/wiki\/National_Aeronautics_and_Space_Administration \"National Aeronautics and Space Administration\") (NASA) has investigated fuel consumption in [microgravity](https:\/\/en.wikipedia.org\/wiki\/Microgravity \"Microgravity\").\n\nThe common distribution of a flame under normal gravity conditions depends on [convection](https:\/\/en.wikipedia.org\/wiki\/Convection \"Convection\"), because soot tends to rise to the top of a flame, such as in a candle, making the flame yellow. In microgravity or [zero gravity](https:\/\/en.wikipedia.org\/wiki\/Zero_gravity \"Zero gravity\"), such as an environment in [outer space](https:\/\/en.wikipedia.org\/wiki\/Outer_space \"Outer space\"), convection no longer occurs, and the flame becomes [spherical](https:\/\/en.wikipedia.org\/wiki\/Sphere \"Sphere\"), with a tendency to become more blue and more efficient. There are several possible explanations for this difference, of which the most likely one given is the hypothesis that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs., National Aeronautics and Space Administration, April 2005. Experiments by NASA in microgravity reveal that [diffusion flames](https:\/\/en.wikipedia.org\/wiki\/Diffusion_flame \"Diffusion flame\") in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions.[LSP-1 experiment results](https:\/\/web.archive.org\/web\/20070312020123\/http:\/\/microgravity.grc.nasa.gov\/combustion\/lsp\/lsp1_results.htm), National Aeronautics and Space Administration, April 2005. [Premixed flames](https:\/\/en.wikipedia.org\/wiki\/Premixed_flame \"Premixed flame\") in microgravity burn at a much slower rate and more efficiently than even a candle on Earth, and last much longer.[\\[20\\]](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_note-20)\n\n- [Annual fuel utilization efficiency](https:\/\/en.wikipedia.org\/wiki\/Annual_fuel_utilization_efficiency \"Annual fuel utilization efficiency\") (AFUE)\n- [ACEA agreement](https:\/\/en.wikipedia.org\/wiki\/ACEA_agreement \"ACEA agreement\")\n- [Alternative propulsion](https:\/\/en.wikipedia.org\/wiki\/Alternative_propulsion \"Alternative propulsion\")\n- [Camless piston engine](https:\/\/en.wikipedia.org\/wiki\/Camless_piston_engine \"Camless piston engine\")\n- [Carbon dioxide equivalent](https:\/\/en.wikipedia.org\/wiki\/Carbon_dioxide_equivalent \"Carbon dioxide equivalent\")\n- [Corporate Average Fuel Economy](https:\/\/en.wikipedia.org\/wiki\/Corporate_Average_Fuel_Economy \"Corporate Average Fuel Economy\") (CAFE)\n- [EcoAuto](https:\/\/en.wikipedia.org\/wiki\/EcoAuto \"EcoAuto\") (in Canada)\n- [Efficient energy use](https:\/\/en.wikipedia.org\/wiki\/Efficient_energy_use \"Efficient energy use\")\n- [Emission standard](https:\/\/en.wikipedia.org\/wiki\/Emission_standard \"Emission standard\")\n- [Energy content of Biofuel](https:\/\/en.wikipedia.org\/wiki\/Energy_content_of_Biofuel \"Energy content of Biofuel\")\n- [Energy conservation](https:\/\/en.wikipedia.org\/wiki\/Energy_conservation \"Energy conservation\")\n- [Energy conversion efficiency](https:\/\/en.wikipedia.org\/wiki\/Energy_conversion_efficiency \"Energy conversion efficiency\")\n- [Energy density](https:\/\/en.wikipedia.org\/wiki\/Energy_density \"Energy density\")\n- [FF layout](https:\/\/en.wikipedia.org\/wiki\/FF_layout \"FF layout\")\n- [Front-wheel drive](https:\/\/en.wikipedia.org\/wiki\/Front-wheel_drive \"Front-wheel drive\")\n- [Fuel economy in aircraft](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy_in_aircraft \"Fuel economy in aircraft\")\n- [Fuel economy in automobiles](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy_in_automobiles \"Fuel economy in automobiles\")\n- [Fuel economy maximising behaviors](https:\/\/en.wikipedia.org\/wiki\/Fuel_economy-maximizing_behaviors \"Fuel economy-maximizing behaviors\")\n- [Fuel efficiency in transportation](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency_in_transportation \"Fuel efficiency in transportation\")\n- [Gas-guzzler](https:\/\/en.wikipedia.org\/wiki\/Gas-guzzler \"Gas-guzzler\")\n- [Heating value](https:\/\/en.wikipedia.org\/wiki\/Heating_value \"Heating value\")\n- [Jevons paradox](https:\/\/en.wikipedia.org\/wiki\/Jevons_paradox \"Jevons paradox\")\n- [Life cycle assessment](https:\/\/en.wikipedia.org\/wiki\/Life_cycle_assessment \"Life cycle assessment\")\n- [Low-rolling resistance tires](https:\/\/en.wikipedia.org\/wiki\/Low-rolling_resistance_tires \"Low-rolling resistance tires\")\n- [Miles per gallon gasoline equivalent](https:\/\/en.wikipedia.org\/wiki\/Miles_per_gallon_gasoline_equivalent \"Miles per gallon gasoline equivalent\")\n- [Marine fuel management](https:\/\/en.wikipedia.org\/wiki\/Marine_fuel_management \"Marine fuel management\")\n- [Twinjet](https:\/\/en.wikipedia.org\/wiki\/Twinjet \"Twinjet\")\n- [Variable valve timing](https:\/\/en.wikipedia.org\/wiki\/Variable_valve_timing \"Variable valve timing\")\n- [Unibody](https:\/\/en.wikipedia.org\/wiki\/Vehicle_frame#Unibody \"Vehicle frame\")\n- [Automobile costs](https:\/\/en.wikipedia.org\/wiki\/Automobile_costs \"Automobile costs\")\n- [Vehicle metrics](https:\/\/en.wikipedia.org\/wiki\/Vehicle_metrics \"Vehicle metrics\")\n\n1. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-1)**\n   [\"Information on the fuel consumption of new cars\"](https:\/\/web.archive.org\/web\/20190908124154\/http:\/\/www.bilsweden.se\/miljo-sakerhet\/miljo\/information-gallande-bransleforbrukning-for-nya-bilar). Archived from [the original](http:\/\/www.bilsweden.se\/miljo-sakerhet\/miljo\/information-gallande-bransleforbrukning-for-nya-bilar) on 8 September 2019. Retrieved 7 November 2019.\n2. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-2)**\n   [\"Learn More About the Fuel Economy Label for Gasoline Vehicles\"](https:\/\/www.fueleconomy.gov\/feg\/label\/learn-more-gasoline-label.shtml#fuel-consumption-rate). [Archived](https:\/\/web.archive.org\/web\/20130705143242\/http:\/\/www.fueleconomy.gov\/feg\/label\/learn-more-gasoline-label.shtml#fuel-consumption-rate) from the original on 2013-07-05.\n3. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-3)**\n   [\"Simple tips and tricks to increase fuel efficiency of your car \\| CarSangrah\"](https:\/\/www.carsangrah.com\/blog\/simple-tips-tricks-enhance-fuel-efficiency-car). *CarSangrah*. 2018-06-07. Retrieved 2018-07-24.\n4. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-4)**\n   [\"How Hybrids Work\"](https:\/\/www.fueleconomy.gov\/). [U.S. Department of Energy](https:\/\/en.wikipedia.org\/wiki\/U.S._Department_of_Energy \"U.S. Department of Energy\"). [Archived](https:\/\/web.archive.org\/web\/20150708093450\/http:\/\/www.fueleconomy.gov\/) from the original on 2015-07-08. Retrieved 2014-01-16.\n5. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-EPA_AutomotiveTrends_202212_5-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-EPA_AutomotiveTrends_202212_5-1)\n   [\"Highlights of the Automotive Trends Report\"](https:\/\/www.epa.gov\/automotive-trends\/highlights-automotive-trends-report). *EPA.gov*. U.S. Environmental Protection Agency (EPA). 12 December 2022. [Archived](https:\/\/web.archive.org\/web\/20230902145941\/https:\/\/www.epa.gov\/automotive-trends\/highlights-automotive-trends-report) from the original on 2 September 2023.\n6. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-GlobalFuelEfficInit_202311_6-0)**\n   Cazzola, Pierpaolo; Paoli, Leonardo; Teter, Jacob (November 2023). [\"Trends in the Global Vehicle Fleet 2023 \/ Managing the SUV Shift and the EV Transition\"](https:\/\/www.globalfueleconomy.org\/media\/792523\/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf) (PDF). Global Fuel Economy Initiative (GFEI). p. 3. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\$identifier\$ \"Doi (identifier)\"):[10\\.7922\/G2HM56SV](https:\/\/doi.org\/10.7922%2FG2HM56SV). [Archived](https:\/\/web.archive.org\/web\/20231126092826\/https:\/\/www.globalfueleconomy.org\/media\/792523\/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf) (PDF) from the original on 26 November 2023.\n7. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-7)** Calculated from heats of formation. Does not correspond exactly to the figure for MJ\/L divided by density.\n8. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-TEDB_8-0)** [Appendix B, Transportation Energy Data Book](http:\/\/www-cta.ornl.gov\/data\/Appendix_B.html) from the [Center for Transportation Analysis](https:\/\/en.wikipedia.org\/wiki\/Center_for_Transportation_Analysis \"Center for Transportation Analysis\") of the [Oak Ridge National Laboratory](https:\/\/en.wikipedia.org\/wiki\/Oak_Ridge_National_Laboratory \"Oak Ridge National Laboratory\")\n9. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-9)**\n   [\"Efficiency\"](http:\/\/www.merriam-webster.com\/dictionary\/efficiency). Retrieved 18 September 2016.\n10. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_fueleco_10-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_fueleco_10-1)\n    [*Assessment of Fuel Economy Technologies for Light-duty Vehicles*](http:\/\/www.nap.edu\/read\/12924\/chapter\/4). The National Academies Press. 2011. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\$identifier\$ \"Doi (identifier)\"):[10\\.17226\/12924](https:\/\/doi.org\/10.17226%2F12924). [ISBN](https:\/\/en.wikipedia.org\/wiki\/ISBN_\$identifier\$ \"ISBN (identifier)\")\n    \n    [978-0-309-15607-3](https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/978-0-309-15607-3 \"Special:BookSources\/978-0-309-15607-3\")\n    \n    . Retrieved 18 September 2016.\n11. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_DOEgloss_11-0)**\n    [\"Glossary of energy-related terms\"](http:\/\/energy.gov\/eere\/energybasics\/articles\/glossary-energy-related-terms#E). [U.S. Department of Energy](https:\/\/en.wikipedia.org\/wiki\/U.S._Department_of_Energy \"U.S. Department of Energy\"). Retrieved 20 September 2016.\n12. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-12)**\n    Page, Walter Hines; Page, Arthur Wilson (1916). [\"Man and His Machines\"](https:\/\/books.google.com\/books?id=lPAMVa7esS4C). *The World's Work*. Vol. XXXIII. Garden City, New York: Doubleday, Page & Co.\n13. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy-efficient_driving_Beusen_13-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy-efficient_driving_Beusen_13-1)\n    Beusen; et al. (2009). [\"Using on-board logging devices to study the long-term impact of an eco-driving course\"](https:\/\/www.researchgate.net\/publication\/231614817). *Transportation Research D*. **14** (7): 514–520\\. [Bibcode](https:\/\/en.wikipedia.org\/wiki\/Bibcode_\$identifier\$ \"Bibcode (identifier)\"):[2009TRPD...14..514B](https:\/\/ui.adsabs.harvard.edu\/abs\/2009TRPD...14..514B). [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\$identifier\$ \"Doi (identifier)\"):[10\\.1016\/j.trd.2009.05.009](https:\/\/doi.org\/10.1016%2Fj.trd.2009.05.009). [Archived](https:\/\/web.archive.org\/web\/20131019115218\/http:\/\/www.researchgate.net\/publication\/231614817_Using_on-board_logging_devices_to_study_the_long-term_impact_of_an_eco-driving_course?ev=prf_pub) from the original on 2013-10-19.\n14. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-14)**\n    [\"20 Ways to Improve Your Fuel Efficiency and Save Money at the Pump\"](http:\/\/car1.ca\/blog\/2016\/08\/02\/20-ways-to-improve-your-fuel-efficiency-and-save-money-at-the-pump\/). [Archived](https:\/\/web.archive.org\/web\/20160816132350\/http:\/\/car1.ca\/blog\/2016\/08\/02\/20-ways-to-improve-your-fuel-efficiency-and-save-money-at-the-pump\/) from the original on 2016-08-16.\n15. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Energy-efficient_driving_merriam-webster.com_15-0)** <http:\/\/www.merriam-webster.com\/dictionary\/hypermiling> Merriam Webster dictionary\n16. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-16)**\n    [\"Staying Ahead Of The Curve: 3 Key Fleet Management Trends For 2023\"](https:\/\/www.forbes.com\/councils\/forbestechcouncil\/2023\/04\/18\/staying-ahead-of-the-curve-3-key-fleet-management-trends-for-2023\/). *Forbes*. April 18, 2023. Retrieved October 7, 2025.\n17. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-17)**\n    [\"Rail 10 times better than air in London-Paris CO2 comparison - Transport & Environment\"](http:\/\/www.transportenvironment.org\/Article267.html). [Archived](https:\/\/web.archive.org\/web\/20070928024427\/http:\/\/www.transportenvironment.org\/Article267.html) from the original on 2007-09-28.\n18. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-Top_Tier_Gasoline_18-0)** [Top Tier Gasoline](http:\/\/www.toptiergas.com\/retailers.html) [Archived](https:\/\/web.archive.org\/web\/20130815031514\/http:\/\/www.toptiergas.com\/retailers.html) 2013-08-15 at the [Wayback Machine](https:\/\/en.wikipedia.org\/wiki\/Wayback_Machine \"Wayback Machine\")\n19. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-19)**\n    [\"Deposit Control Standards\"](https:\/\/web.archive.org\/web\/20040806012056\/http:\/\/www.toptiergas.com\/deposit_control.html). Archived from [the original](http:\/\/www.toptiergas.com\/deposit_control.html) on 2004-08-06. Retrieved 2012-10-19.\n20. **[^](https:\/\/en.wikipedia.org\/wiki\/Fuel_efficiency#cite_ref-20)** [SOFBAL-2 experiment results](https:\/\/microgravity.grc.nasa.gov\/combustion\/lsp\/lsp1_results.htm) [Archived](https:\/\/web.archive.org\/web\/20070312020123\/http:\/\/microgravity.grc.nasa.gov\/combustion\/lsp\/lsp1_results.htm) 2007-03-12 at the [Wayback Machine](https:\/\/en.wikipedia.org\/wiki\/Wayback_Machine \"Wayback Machine\"), National Aeronautics and Space Administration, April 2005.\n\n- [US Government website on fuel economy](https:\/\/www.fueleconomy.gov\/)\n- [UK DfT comparisons on road and rail](http:\/\/www.dft.gov.uk\/stellent\/groups\/dft_railways\/documents\/page\/dft_railways_611287.pdf)\n- [NASA Offers a \\$1.5 Million Prize for a Fast and Fuel-Efficient Aircraft](http:\/\/apps1.eere.energy.gov\/news\/news_detail.cfm\/news_id=12694) [Archived](https:\/\/web.archive.org\/web\/20160303200449\/http:\/\/apps1.eere.energy.gov\/news\/news_detail.cfm\/news_id=12694) 2016-03-03 at the [Wayback Machine](https:\/\/en.wikipedia.org\/wiki\/Wayback_Machine \"Wayback Machine\")\n- [Car Fuel Consumption Official Figures](http:\/\/www.carfuelconsumption.com\/)\n- [Spritmonitor.de \"the most fuel efficient cars\" - Database of thousands of (mostly German) car owners' actual fuel consumption figures](https:\/\/www.spritmonitor.de\/de\/die_sparsamsten_autos.html) (cf. [Spritmonitor](https:\/\/en.wikipedia.org\/wiki\/Spritmonitor \"Spritmonitor\"))\n- [Searchable fuel economy data from the EPA - United States Environmental Protection Agency](https:\/\/web.archive.org\/web\/20131029195658\/http:\/\/fueleconomy.carconsumption.com\/)\n- [penghemat bbm - Alat penghemat bbm](http:\/\/www.xpower-ionizer.com\/)\n- [Ny Times: A Road Test of Alternative Fuel Visions](https:\/\/www.nytimes.com\/2014\/11\/18\/science\/earth\/hydrogen-cars-join-electric-models-in-showrooms.html)","meta_canonical":null,"ml_categories_json":"{\"\/Science\":882,\"\/Science\/Engineering_and_Technology\":772,\"\/Science\/Engineering_and_Technology\/Other\":767,\"\/Autos_and_Vehicles\":321,\"\/Autos_and_Vehicles\/Motor_Vehicles_(By_Type)\":242,\"\/Autos_and_Vehicles\/Motor_Vehicles_(By_Type)\/Other\":133}","ml_types_json":"{\"\/Article\":999,\"\/Article\/Wiki\":949}","ml_intent_types_json":"{\"Informational\":999}","meta_language":"en","attrs_author":null,"attrs_publish_time":0,"attrs_original_publish_time":1375989515,"attrs_is_republished":0,"attrs_nr_words":"4268","attrs_boilerpipe_nr_words":"3328","body_ext_links_number":70,"body_int_links_number":439,"meta_nofollow":0,"meta_noarchive":0,"props_was_rendered":0,"src_redirect":"","download_time_msec":135,"download_ttfb_msec":132,"download_size":38821}

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From Wikipedia, the free encyclopedia Fuel efficiency (or fuel economy ) is a form of thermal efficiency , meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier ( fuel ) into kinetic energy or work . Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile . Non-transportation applications, such as industry , benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion , such as ammonia production during the Haber process . In the context of transport , fuel economy is the energy efficiency of a particular vehicle, given as a ratio of distance traveled per unit of fuel consumed. It is dependent on several factors including engine efficiency , transmission design, and tire design. In most countries, using the metric system , fuel economy is stated as "fuel consumption" in liters per 100 kilometers (L/100 km) or kilometers per liter (km/L or kmpl). In a number of countries still using other systems, fuel economy is expressed in miles per gallon (mpg), for example in the US and usually also in the UK ( imperial gallon); there is sometimes confusion as the imperial gallon is 20% larger than the US gallon so that mpg values are not directly comparable. Traditionally, litres per mil were used in Norway and Sweden , but both have aligned to the EU standard of L/100 km. [ 1 ] Fuel consumption is a more accurate measure of a vehicle's performance because it is a linear relationship while fuel economy leads to distortions in efficiency improvements. [ 2 ] Weight-specific efficiency (efficiency per unit weight) may be stated for freight , and passenger-specific efficiency (vehicle efficiency per passenger) for passenger vehicles. Fuel efficiency is dependent on many parameters of a vehicle, including its engine parameters, aerodynamic drag , weight, AC usage, fuel and rolling resistance . There have been advances in all areas of vehicle design in recent decades. Fuel efficiency of vehicles can also be improved by careful maintenance and driving habits. [ 3 ] Hybrid vehicles use two or more power sources for propulsion. In many designs, a small combustion engine is combined with electric motors. Kinetic energy which would otherwise be lost to heat during braking is recaptured as electrical power to improve fuel efficiency. The larger batteries in these vehicles power the car's electronics , allowing the engine to shut off and avoid prolonged idling . [ 4 ] Trucks' share of US vehicles produced, has tripled since 1975. Though vehicle fuel efficiency has increased within each category, the overall trend toward less efficient types of vehicles has offset some of the benefits of greater fuel economy and reduction in carbon dioxide emissions. [ 5 ] Without the shift towards SUVs, energy use per unit distance could have fallen 30% more than it did from 2010 to 2022. [ 6 ] Fleet efficiency describes the average efficiency of a population of vehicles. Technological advances in efficiency may be offset by a change in buying habits with a propensity to heavier vehicles that are less fuel-efficient. [ 5 ] Energy efficiency terminology [ edit ] Energy efficiency is similar to fuel efficiency but the input is usually in units of energy such as megajoules (MJ), kilowatt-hours (kW·h), kilocalories (kcal) or British thermal units (BTU). The inverse of "energy efficiency" is " energy intensity ", or the amount of input energy required for a unit of output such as MJ/passenger-km (of passenger transport), BTU/ton-mile or kJ/t-km (of freight transport), GJ/t (for production of steel and other materials), BTU/(kW·h) (for electricity generation), or litres/100 km (of vehicle travel). Litres per 100 km is also a measure of "energy intensity" where the input is measured by the amount of fuel and the output is measured by the distance travelled. For example: Fuel economy in automobiles . Given a heat value of a fuel, it would be trivial to convert from fuel units (such as litres of gasoline) to energy units (such as MJ) and conversely. But there are two problems with comparisons made using energy units: There are two different heat values for any hydrogen-containing fuel which can differ by several percent (see below). When comparing transportation energy costs, a kilowatt hour of electric energy may require an amount of fuel with heating value of 2 or 3 kilowatt hours to produce it. Energy content of fuel [ edit ] The specific energy content of a fuel is the heat energy obtained when a certain quantity is burned (such as a gallon, litre, kilogram). It is sometimes called the heat of combustion . There exists two different values of specific heat energy for the same batch of fuel. One is the high (or gross) heat of combustion and the other is the low (or net) heat of combustion. The high value is obtained when, after the combustion, the water in the exhaust is in liquid form. For the low value, the exhaust has all the water in vapor form (steam). Since water vapor gives up heat energy when it changes from vapor to liquid, the liquid water value is larger since it includes the latent heat of vaporization of water. The difference between the high and low values is significant, about 8 or 9%. This accounts for most of the apparent discrepancy in the heat value of gasoline. In the U.S. (and the table) the high heat values have traditionally been used, but in many other countries, the low heat values are commonly used. Fuel type MJ/L MJ/kg BTU / imp gal BTU/ US gal Research octane number (RON) Regular gasoline /petrol 34.8 ~47 150,100 125,000 Min. 91 Premium gasoline /petrol ~46 Min. 95 Autogas ( LPG ) (60% propane and 40% butane ) 25.5–28.7 ~51 108–110 Ethanol 23.5 31.1 [ 7 ] 101,600 84,600 129 Methanol 17.9 19.9 77,600 64,600 123 Gasohol (10% ethanol and 90% gasoline) 33.7 ~45 145,200 121,000 93/94 E85 (85% ethanol and 15% gasoline) 25.2 ~33 108,878 90,660 100–105 Diesel 38.6 ~48 166,600 138,700 N/A (see cetane) Biodiesel 35.1 39.9 151,600 126,200 N/A (see cetane) Vegetable oil (using 9.00 kcal/g) 34.3 37.7 147,894 123,143 Aviation gasoline 33.5 46.8 144,400 120,200 80-145 Jet fuel , naphtha 35.5 46.6 153,100 127,500 N/A to turbine engines Jet fuel , kerosene 37.6 ~47 162,100 135,000 N/A to turbine engines Liquefied natural gas 25.3 ~55 109,000 90,800 Liquid hydrogen 9.3 ~130 40,467 33,696 [ 8 ] Neither the gross heat of combustion nor the net heat of combustion gives the theoretical amount of mechanical energy (work) that can be obtained from the reaction. (This is given by the change in Gibbs free energy , and is around 45.7 MJ/kg for gasoline.) The actual amount of mechanical work obtained from fuel (the inverse of the specific fuel consumption ) depends on the engine. A figure of 17.6 MJ/kg is possible with a gasoline engine, and 19.1 MJ/kg for a diesel engine. See Brake-specific fuel consumption for more information. [ clarification needed ] The energy efficiency in transport is the useful travelled distance , of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in liquid fuels , electrical energy or food energy . [ 9 ] [ 10 ] The energy efficiency is also occasionally known as energy intensity . [ 11 ] The inverse of the energy efficiency in transport is the energy consumption in transport. Energy efficiency in transport is often described in terms of fuel consumption , fuel consumption being the reciprocal of fuel economy. [ 10 ] Nonetheless, fuel consumption is linked with a means of propulsion which uses liquid fuels , whilst energy efficiency is applicable to any sort of propulsion. To avoid said confusion, and to be able to compare the energy efficiency in any type of vehicle, experts tend to measure the energy in the International System of Units , i.e., joules . Therefore, in the International System of Units, the energy efficiency in transport is measured in terms of metre per joule, or m/J, while the energy consumption in transport is measured in terms of joules per metre, or J/m. The more efficient the vehicle, the more metres it covers with one joule (more efficiency), or the fewer joules it uses to travel over one metre (less consumption). The energy efficiency in transport largely varies by means of transport. Different types of transport range from some hundred kilojoules per kilometre (kJ/km) for a bicycle to tens of megajoules per kilometre (MJ/km) for a helicopter . Via type of fuel used and rate of fuel consumption, energy efficiency is also often related to operating cost ($/km) and environmental emissions (e.g. CO 2 /km). Fuel efficiency of motor vehicles [ edit ] New light-duty vehicle fuel economy by vehicle type from vehicle manufacturers in the United States, in miles per gallon (1975 - 2019) Fuel consumption monitor from a 2006 Honda Airwave . The displayed fuel economy is 18.1 km/L (5.5 L/100 km; 43 mpg ‑US ). A Briggs and Stratton Flyer from 1916. Originally an experiment in creating a fuel-saving automobile in the United States, the vehicle weighed only 135 lb (61.2 kg) and was an adaptation of a small gasoline engine originally designed to power a bicycle. [ 12 ] The fuel economy or fuel efficiency of an automobile relates to the distance traveled by a vehicle and the amount of fuel consumed. It can be expressed in terms of the volume of fuel to travel a given distance, such as in litres per 100 kilometres (L/100 km), or through its inverse, the distance traveled per unit volume of fuel consumed, as in kilometres per litre (km/L) or miles per gallon (mpg). Since fuel economy of vehicles is a significant factor in air pollution , the importation of motor fuel can be a large part of a nation's foreign trade and consumers frequently undervalue fuel efficiency, many countries impose requirements for fuel economy. Different methods are used to approximate the actual performance of the vehicle. The energy in fuel is required to overcome various losses ( wind resistance , tire drag , and others) encountered while propelling the vehicle, and in providing power to vehicle systems such as ignition or air conditioning. Various strategies can be employed to reduce losses at each of the conversions between the chemical energy in the fuel and the kinetic energy of the vehicle. Driver behavior can affect fuel economy; maneuvers such as sudden acceleration and heavy braking waste energy. Electric cars use kilowatt-hours of electricity per 100 kilometres (kWh/100km); in the U.S., an equivalence measure, such as miles per gallon gasoline equivalent (US gallon) has been created to attempt to compare them. Energy-efficient driving techniques are used by drivers who wish to reduce their fuel consumption, and thus maximize fuel efficiency. Many drivers have the potential to improve their fuel efficiency significantly. [ 13 ] Simple things such as keeping tires properly inflated, having a vehicle well-maintained and avoiding idling can dramatically improve fuel efficiency. [ 14 ] Careful use of acceleration and deceleration and especially limiting use of high speeds helps efficiency. The use of multiple such techniques is called " hypermiling ". [ 15 ] While these techniques can be applied by any driver, energy-efficient driving (often called "eco-driving") has become a major focus of modern fleet management . As a key part of fleet digitalization , companies use telematics to automatically monitor and manage fuel economy. A fleet telematics system collects data on behaviors that waste fuel, such as harsh acceleration, speeding, and idling. This information is then used in driver scoring applications to identify and coach drivers. [ 13 ] This is often combined with dedicated fuel-management systems that use high-precision fuel level sensors to get exact fuel consumption data and prevent gasoline theft . [ 16 ] Simple fuel-efficiency techniques can result in reduction in fuel consumption without resorting to radical fuel-saving techniques that can be unlawful and dangerous, such as tailgating larger vehicles. Advanced technology [ edit ] The most efficient machines for converting energy to rotary motion are electric motors, as used in electric vehicles . However, electricity is not a primary energy source so the efficiency of the electricity production has also to be taken into account. Railway trains can be powered using electricity, delivered through an additional running rail, overhead catenary system or by on-board generators used in diesel-electric locomotives as common on the US and UK rail networks. Pollution produced from centralised generation of electricity is emitted at a distant power station, rather than "on site". Pollution can be reduced by using more railway electrification and low carbon power for electricity. Some railways, such as the French SNCF and Swiss federal railways derive most, if not 100% of their power, from hydroelectric or nuclear power stations, therefore atmospheric pollution from their rail networks is very low. This was reflected in a study by AEA Technology between a Eurostar train and airline journeys between London and Paris, which showed the trains on average emitting 10 times less CO 2 , per passenger, than planes, helped in part by French nuclear generation. [ 17 ] Hydrogen fuel cells [ edit ] In the future, hydrogen cars may be commercially available. Toyota is test-marketing vehicles powered by hydrogen fuel cells in southern California, where a series of hydrogen fueling stations has been established. Powered either through chemical reactions in a fuel cell that create electricity to drive very efficient electrical motors or by directly burning hydrogen in a combustion engine (near identically to a natural gas vehicle , and similarly compatible with both natural gas and gasoline); these vehicles promise to have near-zero pollution from the tailpipe (exhaust pipe). Potentially the atmospheric pollution could be minimal, provided the hydrogen is made by electrolysis using electricity from non-polluting sources such as solar, wind or hydroelectricity or nuclear. Commercial hydrogen production uses fossil fuels and produces more carbon dioxide than hydrogen. Because there are pollutants involved in the manufacture and destruction of a car and the production, transmission and storage of electricity and hydrogen, the label "zero pollution" applies only to the car's conversion of stored energy into movement. In 2004, a consortium of major auto-makers — BMW , General Motors , Honda , Toyota and Volkswagen / Audi — came up with "Top Tier Detergent Gasoline Standard" to gasoline brands in the US and Canada that meet their minimum standards for detergent content [ 18 ] and do not contain metallic additives. Top Tier gasoline contains higher levels of detergent additives in order to prevent the build-up of deposits (typically, on fuel injector and intake valve ) known to reduce fuel economy and engine performance. [ 19 ] How fuel combusts affects how much energy is produced. The National Aeronautics and Space Administration (NASA) has investigated fuel consumption in microgravity . The common distribution of a flame under normal gravity conditions depends on convection , because soot tends to rise to the top of a flame, such as in a candle, making the flame yellow. In microgravity or zero gravity , such as an environment in outer space , convection no longer occurs, and the flame becomes spherical , with a tendency to become more blue and more efficient. There are several possible explanations for this difference, of which the most likely one given is the hypothesis that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs., National Aeronautics and Space Administration, April 2005. Experiments by NASA in microgravity reveal that diffusion flames in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions. LSP-1 experiment results , National Aeronautics and Space Administration, April 2005. Premixed flames in microgravity burn at a much slower rate and more efficiently than even a candle on Earth, and last much longer. [ 20 ] Annual fuel utilization efficiency (AFUE) ACEA agreement Alternative propulsion Camless piston engine Carbon dioxide equivalent Corporate Average Fuel Economy (CAFE) EcoAuto (in Canada) Efficient energy use Emission standard Energy content of Biofuel Energy conservation Energy conversion efficiency Energy density FF layout Front-wheel drive Fuel economy in aircraft Fuel economy in automobiles Fuel economy maximising behaviors Fuel efficiency in transportation Gas-guzzler Heating value Jevons paradox Life cycle assessment Low-rolling resistance tires Miles per gallon gasoline equivalent Marine fuel management Twinjet Variable valve timing Unibody Automobile costs Vehicle metrics ^ "Information on the fuel consumption of new cars" . Archived from the original on 8 September 2019 . Retrieved 7 November 2019 . ^ "Learn More About the Fuel Economy Label for Gasoline Vehicles" . Archived from the original on 2013-07-05. ^ "Simple tips and tricks to increase fuel efficiency of your car | CarSangrah" . CarSangrah . 2018-06-07 . Retrieved 2018-07-24 . ^ "How Hybrids Work" . U.S. Department of Energy . Archived from the original on 2015-07-08 . Retrieved 2014-01-16 . ^ a b "Highlights of the Automotive Trends Report" . EPA.gov . U.S. Environmental Protection Agency (EPA). 12 December 2022. Archived from the original on 2 September 2023. ^ Cazzola, Pierpaolo; Paoli, Leonardo; Teter, Jacob (November 2023). "Trends in the Global Vehicle Fleet 2023 / Managing the SUV Shift and the EV Transition" (PDF) . Global Fuel Economy Initiative (GFEI). p. 3. doi : 10.7922/G2HM56SV . Archived (PDF) from the original on 26 November 2023. ^ Calculated from heats of formation. Does not correspond exactly to the figure for MJ/L divided by density. ^ Appendix B, Transportation Energy Data Book from the Center for Transportation Analysis of the Oak Ridge National Laboratory ^ "Efficiency" . Retrieved 18 September 2016 . ^ a b Assessment of Fuel Economy Technologies for Light-duty Vehicles . The National Academies Press. 2011. doi : 10.17226/12924 . ISBN 978-0-309-15607-3 . Retrieved 18 September 2016 . ^ "Glossary of energy-related terms" . U.S. Department of Energy . Retrieved 20 September 2016 . ^ Page, Walter Hines; Page, Arthur Wilson (1916). "Man and His Machines" . The World's Work . Vol. XXXIII. Garden City, New York: Doubleday, Page & Co. ^ a b Beusen; et al. (2009). "Using on-board logging devices to study the long-term impact of an eco-driving course" . Transportation Research D . 14 (7): 514– 520. Bibcode : 2009TRPD...14..514B . doi : 10.1016/j.trd.2009.05.009 . Archived from the original on 2013-10-19. ^ "20 Ways to Improve Your Fuel Efficiency and Save Money at the Pump" . Archived from the original on 2016-08-16. ^ http://www.merriam-webster.com/dictionary/hypermiling Merriam Webster dictionary ^ "Staying Ahead Of The Curve: 3 Key Fleet Management Trends For 2023" . Forbes . April 18, 2023 . Retrieved October 7, 2025 . ^ "Rail 10 times better than air in London-Paris CO2 comparison - Transport & Environment" . Archived from the original on 2007-09-28. ^ Top Tier Gasoline Archived 2013-08-15 at the Wayback Machine ^ "Deposit Control Standards" . Archived from the original on 2004-08-06 . Retrieved 2012-10-19 . ^ SOFBAL-2 experiment results Archived 2007-03-12 at the Wayback Machine , National Aeronautics and Space Administration, April 2005. US Government website on fuel economy UK DfT comparisons on road and rail NASA Offers a $1.5 Million Prize for a Fast and Fuel-Efficient Aircraft Archived 2016-03-03 at the Wayback Machine Car Fuel Consumption Official Figures Spritmonitor.de "the most fuel efficient cars" - Database of thousands of (mostly German) car owners' actual fuel consumption figures (cf. Spritmonitor ) Searchable fuel economy data from the EPA - United States Environmental Protection Agency penghemat bbm - Alat penghemat bbm Ny Times: A Road Test of Alternative Fuel Visions

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[o]") ## Contents move to sidebar hide - [(Top)](https://en.wikipedia.org/wiki/Fuel_efficiency) - [1 Vehicle design](https://en.wikipedia.org/wiki/Fuel_efficiency#Vehicle_design) - [2 Fleet efficiency](https://en.wikipedia.org/wiki/Fuel_efficiency#Fleet_efficiency) - [3 Energy efficiency terminology](https://en.wikipedia.org/wiki/Fuel_efficiency#Energy_efficiency_terminology) - [4 Energy content of fuel](https://en.wikipedia.org/wiki/Fuel_efficiency#Energy_content_of_fuel) - [5 Transportation](https://en.wikipedia.org/wiki/Fuel_efficiency#Transportation) Toggle Transportation subsection - [5\.1 Fuel efficiency of motor vehicles](https://en.wikipedia.org/wiki/Fuel_efficiency#Fuel_efficiency_of_motor_vehicles) - [5\.2 Driving technique](https://en.wikipedia.org/wiki/Fuel_efficiency#Driving_technique) - [6 Advanced technology](https://en.wikipedia.org/wiki/Fuel_efficiency#Advanced_technology) Toggle Advanced technology subsection - [6\.1 Hydrogen fuel cells](https://en.wikipedia.org/wiki/Fuel_efficiency#Hydrogen_fuel_cells) - [6\.2 In microgravity](https://en.wikipedia.org/wiki/Fuel_efficiency#In_microgravity) - [7 See also](https://en.wikipedia.org/wiki/Fuel_efficiency#See_also) - [8 References](https://en.wikipedia.org/wiki/Fuel_efficiency#References) - [9 External links](https://en.wikipedia.org/wiki/Fuel_efficiency#External_links) Toggle the table of contents # Fuel efficiency 8 languages - [العربية](https://ar.wikipedia.org/wiki/%D9%83%D9%81%D8%A7%D8%A1%D8%A9_%D8%A7%D9%84%D9%88%D9%82%D9%88%D8%AF "كفاءة الوقود – Arabic") - [Català](https://ca.wikipedia.org/wiki/Efici%C3%A8ncia_de_combustible "Eficiència de combustible – Catalan") - [فارسی](https://fa.wikipedia.org/wiki/%D8%A8%D8%A7%D8%B2%D8%AF%D9%87%DB%8C_%D8%B3%D9%88%D8%AE%D8%AA "بازدهی سوخت – Persian") - [Bahasa Indonesia](https://id.wikipedia.org/wiki/Efisiensi_bahan_bakar "Efisiensi bahan bakar – Indonesian") - [Bahasa Melayu](https://ms.wikipedia.org/wiki/Kecekapan_bahan_api "Kecekapan bahan api – Malay") - [Türkçe](https://tr.wikipedia.org/wiki/Yak%C4%B1t_verimlili%C4%9Fi "Yakıt verimliliği – Turkish") - [Українська](https://uk.wikipedia.org/wiki/%D0%95%D1%84%D0%B5%D0%BA%D1%82%D0%B8%D0%B2%D0%BD%D1%96%D1%81%D1%82%D1%8C_%D0%BF%D0%B0%D0%BB%D0%B8%D0%B2%D0%B0 "Ефективність палива – Ukrainian") - [中文](https://zh.wikipedia.org/wiki/%E7%87%83%E6%B2%B9%E6%95%88%E7%8E%87 "燃油效率 – Chinese") [Edit links](https://www.wikidata.org/wiki/Special:EntityPage/Q5042317#sitelinks-wikipedia "Edit interlanguage links") - [Article](https://en.wikipedia.org/wiki/Fuel_efficiency "View the content page [c]") - [Talk](https://en.wikipedia.org/wiki/Talk:Fuel_efficiency "Discuss improvements to the content page [t]") English - [Read](https://en.wikipedia.org/wiki/Fuel_efficiency) - [Edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit "Edit this page [e]") - [View 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thermal efficiency | [Infrastructure](https://en.wikipedia.org/wiki/Infrastructure "Infrastructure") | |---| | [![](https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Grand_Coulee_Dam_spillway.jpg/250px-Grand_Coulee_Dam_spillway.jpg)](https://en.wikipedia.org/wiki/File:Grand_Coulee_Dam_spillway.jpg)[Grand Coulee Dam](https://en.wikipedia.org/wiki/Grand_Coulee_Dam "Grand Coulee Dam") | | [Assets](https://en.wikipedia.org/wiki/Fixed_asset "Fixed asset") and facilities [Airports](https://en.wikipedia.org/wiki/Airport "Airport") [Bridges](https://en.wikipedia.org/wiki/Bridge "Bridge") [Broadband](https://en.wikipedia.org/wiki/Broadband "Broadband") [Canals](https://en.wikipedia.org/wiki/Canal "Canal") [Coastal management](https://en.wikipedia.org/wiki/Coastal_management "Coastal management") [Critical infrastructure](https://en.wikipedia.org/wiki/Critical_infrastructure "Critical infrastructure") [Dams](https://en.wikipedia.org/wiki/Dam "Dam") [Electricity](https://en.wikipedia.org/wiki/Electricity_generation "Electricity generation") [Energy](https://en.wikipedia.org/wiki/Energy_development "Energy development") [Hazardous waste](https://en.wikipedia.org/wiki/Hazardous_waste "Hazardous waste") [Hospitals](https://en.wikipedia.org/wiki/Hospital "Hospital") [Irrigation](https://en.wikipedia.org/wiki/Irrigation "Irrigation") [Levees](https://en.wikipedia.org/wiki/Levee "Levee") [Lighthouses](https://en.wikipedia.org/wiki/Lighthouse "Lighthouse") [Parks](https://en.wikipedia.org/wiki/Park "Park") [Pipeline](https://en.wikipedia.org/wiki/Pipeline "Pipeline") [Ports](https://en.wikipedia.org/wiki/Port "Port") [Mass transit](https://en.wikipedia.org/wiki/Public_transport "Public transport") [Public housing](https://en.wikipedia.org/wiki/Public_housing "Public housing") [State schools](https://en.wikipedia.org/wiki/State_school "State school") [Public spaces](https://en.wikipedia.org/wiki/Public_space "Public space") [Rail](https://en.wikipedia.org/wiki/Rail_transport "Rail transport") [Roads](https://en.wikipedia.org/wiki/Road "Road") [Sewage treatment](https://en.wikipedia.org/wiki/Sewage_treatment "Sewage treatment") [Sewerage](https://en.wikipedia.org/wiki/Sewerage "Sewerage") [Sluices](https://en.wikipedia.org/wiki/Sluice "Sluice") [Snow removal](https://en.wikipedia.org/wiki/Snow_removal "Snow removal") [Solid waste](https://en.wikipedia.org/wiki/Municipal_solid_waste "Municipal solid waste") [Telecommunications](https://en.wikipedia.org/wiki/Telecommunications "Telecommunications") [Trails](https://en.wikipedia.org/wiki/Trail "Trail") [Utilities](https://en.wikipedia.org/wiki/Public_utility "Public utility") [Water supply](https://en.wikipedia.org/wiki/Water_supply_network "Water supply network") [Weirs](https://en.wikipedia.org/wiki/Weir "Weir") | | Concepts [Asset management](https://en.wikipedia.org/wiki/Infrastructure_asset_management "Infrastructure asset management") [Appropriation](https://en.wikipedia.org/wiki/Appropriation_$law$ "Appropriation (law)") [Lindahl tax](https://en.wikipedia.org/wiki/Lindahl_tax "Lindahl tax") [Build–operate–transfer](https://en.wikipedia.org/wiki/Build%E2%80%93operate%E2%80%93transfer "Build–operate–transfer") [Design–bid–build](https://en.wikipedia.org/wiki/Design%E2%80%93bid%E2%80%93build "Design–bid–build") [Design–build](https://en.wikipedia.org/wiki/Design%E2%80%93build "Design–build") [Earmark](https://en.wikipedia.org/wiki/Earmark_$politics$ "Earmark (politics)") [European green infrastructure](https://en.wikipedia.org/wiki/European_green_infrastructure "European green infrastructure") [Fixed cost](https://en.wikipedia.org/wiki/Fixed_cost "Fixed cost") [Engineering contracts](https://en.wikipedia.org/wiki/Infrastructure#Engineering "Infrastructure") [Externality](https://en.wikipedia.org/wiki/Externality "Externality") [Government debt](https://en.wikipedia.org/wiki/Government_debt "Government debt") [Green infrastructure](https://en.wikipedia.org/wiki/Green_infrastructure "Green infrastructure") [Life-cycle assessment](https://en.wikipedia.org/wiki/Life-cycle_assessment "Life-cycle assessment") [Maintenance](https://en.wikipedia.org/wiki/Maintenance "Maintenance") [Monopoly](https://en.wikipedia.org/wiki/Natural_monopoly "Natural monopoly") [Property tax](https://en.wikipedia.org/wiki/Property_tax "Property tax") [Public–private partnership](https://en.wikipedia.org/wiki/Public%E2%80%93private_partnership "Public–private partnership") [Public capital](https://en.wikipedia.org/wiki/Public_capital "Public capital") [Public finance](https://en.wikipedia.org/wiki/Public_finance "Public finance") [Public good](https://en.wikipedia.org/wiki/Public_good "Public good") [Public sector](https://en.wikipedia.org/wiki/Public_sector "Public sector") [Renovation](https://en.wikipedia.org/wiki/Renovation "Renovation") [Replacement (upgrade)](https://en.wikipedia.org/wiki/Upgrade "Upgrade") [Spillover](https://en.wikipedia.org/wiki/Spillover_$economics$ "Spillover (economics)") [Supply chain](https://en.wikipedia.org/wiki/Supply_chain "Supply chain") [Tax](https://en.wikipedia.org/wiki/Tax "Tax") | | Issues and ideas [Air traffic control](https://en.wikipedia.org/wiki/Air_traffic_control "Air traffic control") [Brownfield](https://en.wikipedia.org/wiki/Brownfield_land "Brownfield land") [Carbon footprint](https://en.wikipedia.org/wiki/Carbon_footprint "Carbon footprint") [Containerization](https://en.wikipedia.org/wiki/Containerization "Containerization") [Congestion pricing](https://en.wikipedia.org/wiki/Congestion_pricing "Congestion pricing") [Environmental tax](https://en.wikipedia.org/wiki/Environmental_tax "Environmental tax") [Ethanol fuel](https://en.wikipedia.org/wiki/Ethanol_fuel "Ethanol fuel") [Fuel tax](https://en.wikipedia.org/wiki/Fuel_tax "Fuel tax") [Groundwater](https://en.wikipedia.org/wiki/Groundwater "Groundwater") [High-speed rail](https://en.wikipedia.org/wiki/High-speed_rail "High-speed rail") [Hybrid vehicles](https://en.wikipedia.org/wiki/Hybrid_vehicle "Hybrid vehicle") [Land-use planning](https://en.wikipedia.org/wiki/Land-use_planning "Land-use planning") [Mobile data terminal](https://en.wikipedia.org/wiki/Mobile_data_terminal "Mobile data terminal") [Pork barrel](https://en.wikipedia.org/wiki/Pork_barrel "Pork barrel") [Rapid bus transit](https://en.wikipedia.org/wiki/Bus_rapid_transit "Bus rapid transit") [Recycling](https://en.wikipedia.org/wiki/Recycling "Recycling") [Renewables](https://en.wikipedia.org/wiki/Renewable_resource "Renewable resource") [Reverse osmosis](https://en.wikipedia.org/wiki/Reverse_osmosis "Reverse osmosis") [Smart grid](https://en.wikipedia.org/wiki/Smart_grid "Smart grid") [Smart growth](https://en.wikipedia.org/wiki/Smart_growth "Smart growth") [Stormwater](https://en.wikipedia.org/wiki/Stormwater "Stormwater") [Urban sprawl](https://en.wikipedia.org/wiki/Urban_sprawl "Urban sprawl") [Traffic congestion](https://en.wikipedia.org/wiki/Traffic_congestion "Traffic congestion") [Transit-oriented development](https://en.wikipedia.org/wiki/Transit-oriented_development "Transit-oriented development") [Fuel efficiency]() [Waste-to-energy](https://en.wikipedia.org/wiki/Waste-to-energy "Waste-to-energy") [Weatherization](https://en.wikipedia.org/wiki/Weatherization "Weatherization") [Wireless technology](https://en.wikipedia.org/wiki/Wireless "Wireless") | | Fields of study [Architecture](https://en.wikipedia.org/wiki/Architecture "Architecture") [Chemical engineering](https://en.wikipedia.org/wiki/Chemical_engineering "Chemical engineering") [Civil](https://en.wikipedia.org/wiki/Civil_engineering "Civil engineering") [Electrical](https://en.wikipedia.org/wiki/Electrical_engineering "Electrical engineering") [Mechanical engineering](https://en.wikipedia.org/wiki/Mechanical_engineering "Mechanical engineering") [Public economics](https://en.wikipedia.org/wiki/Public_economics "Public economics") [Public policy](https://en.wikipedia.org/wiki/Public_policy "Public policy") [Urban planning](https://en.wikipedia.org/wiki/Urban_planning "Urban planning") | | Examples [Akashi Kaikyo Bridge](https://en.wikipedia.org/wiki/Akashi_Kaikyo_Bridge "Akashi Kaikyo Bridge") [Trans-Alaska pipeline](https://en.wikipedia.org/wiki/Trans-Alaska_Pipeline_System "Trans-Alaska Pipeline System") [Autobahn](https://en.wikipedia.org/wiki/Autobahn "Autobahn") [Bicycle parking station](https://en.wikipedia.org/wiki/Bicycle_parking_station "Bicycle parking station") [Brazilian energy independence](https://en.wikipedia.org/wiki/Energy_in_Brazil "Energy in Brazil") [Brooklyn Bridge](https://en.wikipedia.org/wiki/Brooklyn_Bridge "Brooklyn Bridge") [Channel Tunnel](https://en.wikipedia.org/wiki/Channel_Tunnel "Channel Tunnel") [Chicago wastewater](https://en.wikipedia.org/wiki/Metropolitan_Water_Reclamation_District_of_Greater_Chicago "Metropolitan Water Reclamation District of Greater Chicago") [China's high-speed rail](https://en.wikipedia.org/wiki/High-speed_rail_in_China "High-speed rail in China") [Curtiba rapid bus transit](https://en.wikipedia.org/wiki/Rede_Integrada_de_Transporte "Rede Integrada de Transporte") [Cycling infrastructure](https://en.wikipedia.org/wiki/Cycling_infrastructure "Cycling infrastructure") ([history](https://en.wikipedia.org/wiki/History_of_cycling_infrastructure "History of cycling infrastructure"), [safety](https://en.wikipedia.org/wiki/Safety_of_cycling_infrastructure "Safety of cycling infrastructure")) [Danish wind-power](https://en.wikipedia.org/wiki/Wind_power_in_Denmark "Wind power in Denmark") [British offshore wind-power](https://en.wikipedia.org/wiki/List_of_offshore_wind_farms_in_the_United_Kingdom "List of offshore wind farms in the United Kingdom") [Nuclear power in France](https://en.wikipedia.org/wiki/Nuclear_power_in_France "Nuclear power in France") [Solar power in Germany](https://en.wikipedia.org/wiki/Solar_power_in_Germany "Solar power in Germany") [Hoover Dam](https://en.wikipedia.org/wiki/Hoover_Dam "Hoover Dam") [Hong Kong Int'l Airport](https://en.wikipedia.org/wiki/Hong_Kong_International_Airport "Hong Kong International Airport") [Intercity Express](https://en.wikipedia.org/wiki/Intercity_Express "Intercity Express") [Interstate highways](https://en.wikipedia.org/wiki/Interstate_Highway_System "Interstate Highway System") [Jamnagar Refinery](https://en.wikipedia.org/wiki/Jio-bp#Jamnagar_Refinery "Jio-bp") [Kansai Int'l Airport](https://en.wikipedia.org/wiki/Kansai_International_Airport "Kansai International Airport") [Levee](https://en.wikipedia.org/wiki/Levee "Levee") [Offshore wind port](https://en.wikipedia.org/wiki/Offshore_wind_port "Offshore wind port") [Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal "Panama Canal") [Port of Shanghai](https://en.wikipedia.org/wiki/Port_of_Shanghai "Port of Shanghai") [San Francisco–Oakland Bay Bridge](https://en.wikipedia.org/wiki/San_Francisco%E2%80%93Oakland_Bay_Bridge "San Francisco–Oakland Bay Bridge") [Three Gorges Dam](https://en.wikipedia.org/wiki/Three_Gorges_Dam "Three Gorges Dam") [Shinkansen](https://en.wikipedia.org/wiki/Shinkansen "Shinkansen") [Spanish high-speed rail](https://en.wikipedia.org/wiki/High-speed_rail_in_Spain "High-speed rail in Spain") [French TGV rail](https://en.wikipedia.org/wiki/TGV "TGV") [Spanish autovias and autopistas](https://en.wikipedia.org/wiki/Highways_in_Spain "Highways in Spain") [Transcontinental Railroad](https://en.wikipedia.org/wiki/First_transcontinental_railroad "First transcontinental railroad") [Power transmission in the USA](https://en.wikipedia.org/wiki/Electric_power_transmission#Overhead_transmission "Electric power transmission") [Wind farm](https://en.wikipedia.org/wiki/Wind_farm "Wind farm") | | ![](https://upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/20px-Symbol_category_class.svg.png) [Category](https://en.wikipedia.org/wiki/Category:Infrastructure "Category:Infrastructure") [![icon](https://upload.wikimedia.org/wikipedia/commons/thumb/7/7a/Nuvola_apps_kcmsystem.svg/40px-Nuvola_apps_kcmsystem.svg.png)](https://en.wikipedia.org/wiki/File:Nuvola_apps_kcmsystem.svg) [Engineering portal](https://en.wikipedia.org/wiki/Portal:Engineering "Portal:Engineering") | | [v](https://en.wikipedia.org/wiki/Template:Infrastructure_sidebar "Template:Infrastructure sidebar") [t](https://en.wikipedia.org/wiki/Template_talk:Infrastructure_sidebar "Template talk:Infrastructure sidebar") [e](https://en.wikipedia.org/wiki/Special:EditPage/Template:Infrastructure_sidebar "Special:EditPage/Template:Infrastructure sidebar") | **Fuel efficiency** (or **fuel economy**) is a form of [thermal efficiency](https://en.wikipedia.org/wiki/Thermal_efficiency "Thermal efficiency"), meaning the [ratio](https://en.wikipedia.org/wiki/Ratio "Ratio") of effort to result of a process that converts [chemical](https://en.wikipedia.org/wiki/Chemical_energy "Chemical energy") [potential energy](https://en.wikipedia.org/wiki/Potential_energy "Potential energy") contained in a carrier ([fuel](https://en.wikipedia.org/wiki/Fuel "Fuel")) into kinetic energy or [work](https://en.wikipedia.org/wiki/Mechanical_work "Mechanical work"). Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous [energy profile](https://en.wikipedia.org/wiki/Energy_profile "Energy profile"). Non-transportation applications, such as [industry](https://en.wikipedia.org/wiki/Industrial_sector "Industrial sector"), benefit from increased fuel efficiency, especially [fossil fuel power plants](https://en.wikipedia.org/wiki/Fossil_fuel_power_plant "Fossil fuel power plant") or industries dealing with [combustion](https://en.wikipedia.org/wiki/Combustion "Combustion"), such as [ammonia](https://en.wikipedia.org/wiki/Ammonia "Ammonia") production during the [Haber process](https://en.wikipedia.org/wiki/Haber_process "Haber process"). In the context of [transport](https://en.wikipedia.org/wiki/Transport "Transport"), fuel economy is the [energy efficiency](https://en.wikipedia.org/wiki/Energy_efficiency_in_transportation "Energy efficiency in transportation") of a particular vehicle, given as a [ratio](https://en.wikipedia.org/wiki/Ratio "Ratio") of distance traveled per unit of [fuel](https://en.wikipedia.org/wiki/Motor_fuel "Motor fuel") consumed. It is dependent on several factors including [engine efficiency](https://en.wikipedia.org/wiki/Engine_efficiency "Engine efficiency"), [transmission](https://en.wikipedia.org/wiki/Transmission_$mechanics$ "Transmission (mechanics)") design, and [tire](https://en.wikipedia.org/wiki/Tire "Tire") design. In most countries, using the [metric system](https://en.wikipedia.org/wiki/Metric_system "Metric system"), fuel economy is stated as "fuel consumption" in [liters](https://en.wikipedia.org/wiki/Liter "Liter") per 100 [kilometers](https://en.wikipedia.org/wiki/Kilometers "Kilometers") (L/100 km) or kilometers per liter (km/L or kmpl). In a number of countries still using other systems, fuel economy is expressed in [miles](https://en.wikipedia.org/wiki/Mile "Mile") per [gallon](https://en.wikipedia.org/wiki/Gallon "Gallon") (mpg), for example in the US and usually also in the UK ([imperial](https://en.wikipedia.org/wiki/Imperial_units "Imperial units") gallon); there is sometimes confusion as the imperial gallon is 20% larger than the US gallon so that mpg values are not directly comparable. Traditionally, litres per [mil](https://en.wikipedia.org/wiki/Scandinavian_mile "Scandinavian mile") were used in [Norway](https://en.wikipedia.org/wiki/Norway "Norway") and [Sweden](https://en.wikipedia.org/wiki/Sweden "Sweden"), but both have aligned to the EU standard of L/100 km.[\[1\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-1) Fuel consumption is a more accurate measure of a vehicle's performance because it is a linear relationship while fuel economy leads to distortions in efficiency improvements.[\[2\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-2) Weight-specific efficiency (efficiency per unit weight) may be stated for [freight](https://en.wikipedia.org/wiki/Freight "Freight"), and passenger-specific efficiency (vehicle efficiency per passenger) for passenger vehicles. ## Vehicle design \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=1 "Edit section: Vehicle design")\] Fuel efficiency is dependent on many parameters of a vehicle, including its [engine](https://en.wikipedia.org/wiki/Engine "Engine") parameters, [aerodynamic drag](https://en.wikipedia.org/wiki/Drag_$physics$ "Drag (physics)"), weight, AC usage, fuel and [rolling resistance](https://en.wikipedia.org/wiki/Rolling_resistance "Rolling resistance"). There have been advances in all areas of vehicle design in recent decades. Fuel efficiency of vehicles can also be improved by careful maintenance and driving habits.[\[3\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-3) [Hybrid vehicles](https://en.wikipedia.org/wiki/Hybrid_vehicles "Hybrid vehicles") use two or more power sources for propulsion. In many designs, a small combustion engine is combined with electric motors. Kinetic energy which would otherwise be lost to heat during braking is recaptured as electrical power to improve fuel efficiency. The larger batteries in these vehicles power the [car's electronics](https://en.wikipedia.org/wiki/Automotive_electronics "Automotive electronics"), allowing the engine to shut off and avoid prolonged [idling](https://en.wikipedia.org/wiki/Start-stop_system "Start-stop system").[\[4\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-4) ## Fleet efficiency \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=2 "Edit section: Fleet efficiency")\] [![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/90/1975-_US_vehicle_production_share%2C_by_vehicle_type.svg/250px-1975-_US_vehicle_production_share%2C_by_vehicle_type.svg.png)](https://en.wikipedia.org/wiki/File:1975-_US_vehicle_production_share,_by_vehicle_type.svg) Trucks' share of US vehicles produced, has tripled since 1975. Though vehicle fuel efficiency has increased within each category, the overall trend toward less efficient types of vehicles has offset some of the benefits of greater fuel economy and reduction in carbon dioxide emissions.[\[5\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-EPA_AutomotiveTrends_202212-5) Without the shift towards SUVs, energy use per unit distance could have fallen 30% more than it did from 2010 to 2022.[\[6\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-GlobalFuelEfficInit_202311-6) Fleet efficiency describes the average efficiency of a population of vehicles. Technological advances in efficiency may be offset by a change in buying habits with a propensity to heavier vehicles that are less fuel-efficient.[\[5\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-EPA_AutomotiveTrends_202212-5) ## Energy efficiency terminology \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=3 "Edit section: Energy efficiency terminology")\] [Energy efficiency](https://en.wikipedia.org/wiki/Energy_efficiency_$physics$ "Energy efficiency (physics)") is similar to fuel efficiency but the input is usually in units of energy such as [megajoules](https://en.wikipedia.org/wiki/Megajoules "Megajoules") (MJ), [kilowatt-hours](https://en.wikipedia.org/wiki/Kilowatt-hours "Kilowatt-hours") (kW·h), kilocalories (kcal) or [British thermal units](https://en.wikipedia.org/wiki/British_thermal_units "British thermal units") (BTU). The inverse of "energy efficiency" is "[energy intensity](https://en.wikipedia.org/wiki/Energy_intensity "Energy intensity")", or the amount of input energy required for a unit of output such as MJ/passenger-km (of passenger transport), BTU/ton-mile or kJ/t-km (of freight transport), GJ/t (for production of steel and other materials), BTU/(kW·h) (for electricity generation), or litres/100 km (of vehicle travel). Litres per 100 km is also a measure of "energy intensity" where the input is measured by the amount of fuel and the output is measured by the [distance](https://en.wikipedia.org/wiki/Distance "Distance") travelled. For example: [Fuel economy in automobiles](https://en.wikipedia.org/wiki/Fuel_economy_in_automobiles "Fuel economy in automobiles"). Given a heat value of a fuel, it would be trivial to convert from fuel units (such as litres of gasoline) to energy units (such as MJ) and conversely. But there are two problems with comparisons made using energy units: - There are two different heat values for any hydrogen-containing fuel which can differ by several percent (see below). - When comparing transportation energy costs, a [kilowatt hour](https://en.wikipedia.org/wiki/Kilowatt_hour "Kilowatt hour") of electric energy may require an amount of fuel with heating value of 2 or 3 kilowatt hours to produce it. ## Energy content of fuel \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=4 "Edit section: Energy content of fuel")\] The specific [energy content](https://en.wikipedia.org/wiki/Energy_content "Energy content") of a fuel is the heat energy obtained when a certain quantity is burned (such as a gallon, litre, kilogram). It is sometimes called the [heat of combustion](https://en.wikipedia.org/wiki/Heat_of_combustion "Heat of combustion"). There exists two different values of [specific heat](https://en.wikipedia.org/wiki/Specific_heat "Specific heat") energy for the same batch of fuel. One is the high (or gross) heat of combustion and the other is the low (or net) heat of combustion. The high value is obtained when, after the combustion, the water in the exhaust is in liquid form. For the low value, the exhaust has all the water in vapor form (steam). Since water vapor gives up heat energy when it changes from vapor to liquid, the liquid water value is larger since it includes the [latent heat](https://en.wikipedia.org/wiki/Latent_heat "Latent heat") of vaporization of water. The difference between the high and low values is significant, about 8 or 9%. This accounts for most of the apparent discrepancy in the heat value of gasoline. In the U.S. (and the table) the high heat values have traditionally been used, but in many other countries, the low heat values are commonly used. | Fuel type | MJ/L | MJ/kg | [BTU](https://en.wikipedia.org/wiki/British_thermal_unit "British thermal unit")/[imp gal](https://en.wikipedia.org/wiki/Gallon "Gallon") | BTU/[US gal](https://en.wikipedia.org/wiki/US_gallon "US gallon") | [Research octane number (RON)](https://en.wikipedia.org/wiki/Octane_rating "Octane rating") | |---|---|---|---|---|---| | Regular [gasoline](https://en.wikipedia.org/wiki/Gasoline "Gasoline")/petrol | 34\.8 | ~47 | 150,100 | 125,000 | Min. 91 | | Premium [gasoline](https://en.wikipedia.org/wiki/Gasoline "Gasoline")/petrol | | ~46 | | | Min. 95 | | [Autogas](https://en.wikipedia.org/wiki/Autogas "Autogas") ([LPG](https://en.wikipedia.org/wiki/Liquefied_petroleum_gas "Liquefied petroleum gas")) (60% [propane](https://en.wikipedia.org/wiki/Propane "Propane") and 40% [butane](https://en.wikipedia.org/wiki/Butane "Butane")) | 25\.5–28.7 | ~51 | | | 108–110 | | [Ethanol](https://en.wikipedia.org/wiki/Ethanol_fuel "Ethanol fuel") | 23\.5 | 31\.1[\[7\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-7) | 101,600 | 84,600 | 129 | | [Methanol](https://en.wikipedia.org/wiki/Methanol "Methanol") | 17\.9 | 19\.9 | 77,600 | 64,600 | 123 | | [Gasohol](https://en.wikipedia.org/wiki/Alcohol_fuel "Alcohol fuel") (10% ethanol and 90% gasoline) | 33\.7 | ~45 | 145,200 | 121,000 | 93/94 | | [E85](https://en.wikipedia.org/wiki/E85 "E85") (85% ethanol and 15% gasoline) | 25\.2 | ~33 | 108,878 | 90,660 | 100–105 | | [Diesel](https://en.wikipedia.org/wiki/Diesel_fuel "Diesel fuel") | 38\.6 | ~48 | 166,600 | 138,700 | [N/A (see cetane)](https://en.wikipedia.org/wiki/Cetane_number "Cetane number") | | [Biodiesel](https://en.wikipedia.org/wiki/Biodiesel "Biodiesel") | 35\.1 | 39\.9 | 151,600 | 126,200 | [N/A (see cetane)](https://en.wikipedia.org/wiki/Cetane_number "Cetane number") | | [Vegetable oil](https://en.wikipedia.org/wiki/WVO "WVO") (using 9.00 kcal/g) | 34\.3 | 37\.7 | 147,894 | 123,143 | | | [Aviation gasoline](https://en.wikipedia.org/wiki/Aviation_gasoline "Aviation gasoline") | 33\.5 | 46\.8 | 144,400 | 120,200 | 80-145 | | [Jet fuel](https://en.wikipedia.org/wiki/Jet_fuel "Jet fuel"), naphtha | 35\.5 | 46\.6 | 153,100 | 127,500 | N/A to turbine engines | | [Jet fuel](https://en.wikipedia.org/wiki/Jet_fuel "Jet fuel"), kerosene | 37\.6 | ~47 | 162,100 | 135,000 | N/A to turbine engines | | [Liquefied natural gas](https://en.wikipedia.org/wiki/Liquefied_natural_gas "Liquefied natural gas") | 25\.3 | ~55 | 109,000 | 90,800 | | | [Liquid hydrogen](https://en.wikipedia.org/wiki/Liquid_hydrogen "Liquid hydrogen") | 09\.3 | ~130 | 40,467 | 33,696 | | [\[8\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-TEDB-8) Neither the gross heat of combustion nor the net heat of combustion gives the theoretical amount of mechanical energy (work) that can be obtained from the reaction. (This is given by the change in [Gibbs free energy](https://en.wikipedia.org/wiki/Gibbs_free_energy "Gibbs free energy"), and is around 45.7 MJ/kg for gasoline.) The actual amount of mechanical work obtained from fuel (the inverse of the [specific fuel consumption](https://en.wikipedia.org/wiki/Brake-specific_fuel_consumption "Brake-specific fuel consumption")) depends on the engine. A figure of 17.6 MJ/kg is possible with a gasoline engine, and 19.1 MJ/kg for a diesel engine. See [Brake-specific fuel consumption](https://en.wikipedia.org/wiki/Brake-specific_fuel_consumption "Brake-specific fuel consumption") for more information.\[*[clarification needed](https://en.wikipedia.org/wiki/Wikipedia:Please_clarify "Wikipedia:Please clarify")*\] ## Transportation \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=5 "Edit section: Transportation")\] This section is an excerpt from [Energy efficiency in transport](https://en.wikipedia.org/wiki/Energy_efficiency_in_transport "Energy efficiency in transport").\[[edit](https://en.wikipedia.org/w/index.php?title=Energy_efficiency_in_transport&action=edit)\] The [energy efficiency in transport](https://en.wikipedia.org/wiki/Energy_efficiency_in_transport "Energy efficiency in transport") is the useful travelled [distance](https://en.wikipedia.org/wiki/Distance "Distance"), of passengers, goods or any type of load; divided by the total [energy](https://en.wikipedia.org/wiki/Energy "Energy") put into the transport [propulsion](https://en.wikipedia.org/wiki/Propulsion "Propulsion") means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in [liquid fuels](https://en.wikipedia.org/wiki/Liquid_fuel "Liquid fuel"), [electrical energy](https://en.wikipedia.org/wiki/Electrical_energy "Electrical energy") or [food energy](https://en.wikipedia.org/wiki/Food_energy "Food energy").[\[9\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-9)[\[10\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_fueleco-10) The [energy efficiency](https://en.wikipedia.org/wiki/Efficient_energy_use "Efficient energy use") is also occasionally known as [energy intensity](https://en.wikipedia.org/wiki/Energy_intensity "Energy intensity").[\[11\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_DOEgloss-11) The [inverse](https://en.wikipedia.org/wiki/Multiplicative_inverse "Multiplicative inverse") of the energy efficiency in transport is the energy consumption in transport. Energy efficiency in transport is often described in terms of [fuel consumption](https://en.wikipedia.org/wiki/Fuel_consumption "Fuel consumption"), fuel consumption being the reciprocal of fuel economy.[\[10\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_fueleco-10) Nonetheless, fuel consumption is linked with a means of propulsion which uses [liquid fuels](https://en.wikipedia.org/wiki/Liquid_fuel "Liquid fuel"), whilst energy efficiency is applicable to any sort of propulsion. To avoid said confusion, and to be able to compare the energy efficiency in any type of vehicle, experts tend to measure the energy in the [International System of Units](https://en.wikipedia.org/wiki/International_System_of_Units "International System of Units"), i.e., [joules](https://en.wikipedia.org/wiki/Joule "Joule"). Therefore, in the International System of Units, the energy efficiency in transport is measured in terms of metre per joule, or m/J, while the energy consumption in transport is measured in terms of joules per metre, or J/m. The more efficient the vehicle, the more metres it covers with one joule (more efficiency), or the fewer joules it uses to travel over one metre (less consumption). The [energy efficiency](https://en.wikipedia.org/wiki/Efficient_energy_use "Efficient energy use") in transport largely varies by means of transport. Different types of [transport](https://en.wikipedia.org/wiki/Transportation "Transportation") range from some hundred [kilojoules](https://en.wikipedia.org/wiki/Joule "Joule") per kilometre (kJ/km) for a [bicycle](https://en.wikipedia.org/wiki/Bicycle "Bicycle") to tens of megajoules per kilometre (MJ/km) for a [helicopter](https://en.wikipedia.org/wiki/Helicopter "Helicopter"). Via type of fuel used and rate of fuel consumption, energy efficiency is also often related to operating cost (\$/km) and environmental emissions (e.g. CO2/km). ### Fuel efficiency of motor vehicles \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=6 "Edit section: Fuel efficiency of motor vehicles")\] This section is an excerpt from [Fuel economy in automobiles](https://en.wikipedia.org/wiki/Fuel_economy_in_automobiles "Fuel economy in automobiles").\[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_economy_in_automobiles&action=edit)\] [![](https://upload.wikimedia.org/wikipedia/commons/thumb/3/38/CAFE_performance.svg/250px-CAFE_performance.svg.png)](https://en.wikipedia.org/wiki/File:CAFE_performance.svg) New light-duty vehicle fuel economy by vehicle type from vehicle manufacturers in the United States, in miles per gallon (1975 - 2019) [![](https://upload.wikimedia.org/wikipedia/commons/thumb/3/35/2006_Honda_Airwave_fuel_efficiency_meter.jpg/250px-2006_Honda_Airwave_fuel_efficiency_meter.jpg)](https://en.wikipedia.org/wiki/File:2006_Honda_Airwave_fuel_efficiency_meter.jpg) Fuel consumption monitor from a 2006 [Honda Airwave](https://en.wikipedia.org/wiki/Honda_Airwave "Honda Airwave"). The displayed fuel economy is 18.1 km/L (5.5 L/100 km; 43 mpg‑US). [![](https://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Fuel_Economy%2C_1916.jpg/250px-Fuel_Economy%2C_1916.jpg)](https://en.wikipedia.org/wiki/File:Fuel_Economy,_1916.jpg) A [Briggs and Stratton Flyer](https://en.wikipedia.org/wiki/Briggs_and_Stratton_Flyer "Briggs and Stratton Flyer") from 1916. Originally an experiment in creating a fuel-saving automobile in the United States, the vehicle weighed only 135 lb (61.2 kg) and was an adaptation of a small gasoline engine originally designed to power a bicycle.[\[12\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-12) The [fuel economy](https://en.wikipedia.org/wiki/Fuel_economy_in_automobiles "Fuel economy in automobiles") or fuel efficiency of an [automobile](https://en.wikipedia.org/wiki/Car "Car") relates to the [distance traveled](https://en.wikipedia.org/wiki/Distance_traveled "Distance traveled") by a vehicle and the amount of [fuel](https://en.wikipedia.org/wiki/Fuel "Fuel") consumed. It can be expressed in terms of the volume of fuel to travel a given distance, such as in litres per 100 kilometres (L/100 km), or through its inverse, the distance traveled per unit volume of fuel consumed, as in kilometres per litre (km/L) or miles per gallon (mpg). Since fuel economy of vehicles is a significant factor in [air pollution](https://en.wikipedia.org/wiki/Air_pollution "Air pollution"), the importation of [motor fuel](https://en.wikipedia.org/wiki/Motor_fuel "Motor fuel") can be a large part of a nation's [foreign trade](https://en.wikipedia.org/wiki/Foreign_trade "Foreign trade") and consumers frequently undervalue fuel efficiency, many countries impose requirements for fuel economy. Different methods are used to approximate the actual performance of the vehicle. The energy in fuel is required to overcome various losses ([wind resistance](https://en.wikipedia.org/wiki/Wind_resistance "Wind resistance"), [tire drag](https://en.wikipedia.org/wiki/Tire_drag "Tire drag"), and others) encountered while propelling the vehicle, and in providing power to vehicle systems such as ignition or air conditioning. Various strategies can be employed to reduce losses at each of the conversions between the [chemical energy](https://en.wikipedia.org/wiki/Chemical_energy "Chemical energy") in the fuel and the [kinetic energy](https://en.wikipedia.org/wiki/Kinetic_energy "Kinetic energy") of the vehicle. Driver behavior can affect fuel economy; maneuvers such as sudden acceleration and heavy [braking](https://en.wikipedia.org/wiki/Braking "Braking") waste energy. [Electric cars](https://en.wikipedia.org/wiki/Electric_car "Electric car") use [kilowatt-hours](https://en.wikipedia.org/wiki/Kilowatt-hours "Kilowatt-hours") of electricity per 100 kilometres (kWh/100km); in the U.S., an equivalence measure, such as [miles per gallon gasoline equivalent](https://en.wikipedia.org/wiki/Miles_per_gallon_gasoline_equivalent "Miles per gallon gasoline equivalent") (US gallon) has been created to attempt to compare them. ### Driving technique \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=7 "Edit section: Driving technique")\] This section is an excerpt from [Energy-efficient driving](https://en.wikipedia.org/wiki/Energy-efficient_driving "Energy-efficient driving").\[[edit](https://en.wikipedia.org/w/index.php?title=Energy-efficient_driving&action=edit)\] [Energy-efficient driving](https://en.wikipedia.org/wiki/Energy-efficient_driving "Energy-efficient driving") techniques are used by drivers who wish to reduce their fuel consumption, and thus maximize fuel efficiency. Many drivers have the potential to improve their fuel efficiency significantly.[\[13\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy-efficient_driving_Beusen-13) Simple things such as keeping tires properly inflated, having a vehicle well-maintained and avoiding idling can dramatically improve fuel efficiency.[\[14\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-14) Careful use of acceleration and deceleration and especially limiting use of high speeds helps efficiency. The use of multiple such techniques is called "[hypermiling](https://en.wikipedia.org/wiki/Hypermiling "Hypermiling")".[\[15\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy-efficient_driving_merriam-webster.com-15) While these techniques can be applied by any driver, energy-efficient driving (often called "eco-driving") has become a major focus of modern [fleet management](https://en.wikipedia.org/wiki/Fleet_management "Fleet management"). As a key part of [fleet digitalization](https://en.wikipedia.org/wiki/Fleet_digitalization "Fleet digitalization"), companies use [telematics](https://en.wikipedia.org/wiki/Telematics "Telematics") to automatically monitor and manage fuel economy. A [fleet telematics system](https://en.wikipedia.org/wiki/Fleet_telematics_system "Fleet telematics system") collects data on behaviors that waste fuel, such as harsh acceleration, speeding, and idling. This information is then used in [driver scoring](https://en.wikipedia.org/wiki/Driver_scoring "Driver scoring") applications to identify and coach drivers.[\[13\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy-efficient_driving_Beusen-13) This is often combined with dedicated [fuel-management systems](https://en.wikipedia.org/wiki/Fuel-management_systems "Fuel-management systems") that use high-precision [fuel level sensors](https://en.wikipedia.org/w/index.php?title=Fuel_level_sensor&action=edit&redlink=1 "Fuel level sensor (page does not exist)") to get exact fuel consumption data and prevent [gasoline theft](https://en.wikipedia.org/wiki/Gasoline_theft "Gasoline theft").[\[16\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-16) Simple fuel-efficiency techniques can result in reduction in fuel consumption without resorting to radical fuel-saving techniques that can be unlawful and dangerous, such as tailgating larger vehicles. ## Advanced technology \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=8 "Edit section: Advanced technology")\] The most efficient machines for converting energy to rotary motion are electric motors, as used in [electric vehicles](https://en.wikipedia.org/wiki/Electric_vehicles "Electric vehicles"). However, electricity is not a primary energy source so the efficiency of the electricity production has also to be taken into account. [Railway](https://en.wikipedia.org/wiki/Railway "Railway") trains can be powered using electricity, delivered through an additional running rail, overhead [catenary](https://en.wikipedia.org/wiki/Overhead_lines "Overhead lines") system or by on-board generators used in [diesel-electric](https://en.wikipedia.org/wiki/Diesel-electric_transmission "Diesel-electric transmission") locomotives as common on the US and UK rail networks. Pollution produced from centralised generation of electricity is emitted at a distant power station, rather than "on site". Pollution can be reduced by using more railway electrification and [low carbon power](https://en.wikipedia.org/wiki/Low_carbon_power "Low carbon power") for electricity. Some railways, such as the French SNCF and Swiss federal railways derive most, if not 100% of their power, from hydroelectric or nuclear power stations, therefore atmospheric pollution from their rail networks is very low. This was reflected in a study by AEA Technology between a [Eurostar](https://en.wikipedia.org/wiki/Eurostar "Eurostar") train and airline journeys between London and Paris, which showed the trains on average emitting 10 times less CO2, per passenger, than planes, helped in part by French nuclear generation.[\[17\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-17) ### Hydrogen fuel cells \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=9 "Edit section: Hydrogen fuel cells")\] In the future, [hydrogen cars](https://en.wikipedia.org/wiki/Hydrogen_vehicle "Hydrogen vehicle") may be commercially available. Toyota is test-marketing vehicles powered by hydrogen fuel cells in southern California, where a series of hydrogen fueling stations has been established. Powered either through chemical reactions in a [fuel cell](https://en.wikipedia.org/wiki/Fuel_cell "Fuel cell") that create electricity to drive very efficient electrical motors or by directly burning hydrogen in a combustion engine (near identically to a [natural gas vehicle](https://en.wikipedia.org/wiki/Natural_gas_vehicle "Natural gas vehicle"), and similarly compatible with both natural gas and gasoline); these vehicles promise to have near-zero pollution from the tailpipe (exhaust pipe). Potentially the atmospheric pollution could be minimal, provided the hydrogen is made by [electrolysis](https://en.wikipedia.org/wiki/Electrolysis "Electrolysis") using electricity from non-polluting sources such as solar, wind or [hydroelectricity](https://en.wikipedia.org/wiki/Hydroelectricity "Hydroelectricity") or nuclear. Commercial [hydrogen production](https://en.wikipedia.org/wiki/Hydrogen_production "Hydrogen production") uses fossil fuels and produces more carbon dioxide than hydrogen. Because there are pollutants involved in the manufacture and destruction of a car and the production, transmission and storage of electricity and hydrogen, the label "zero pollution" applies only to the car's conversion of stored energy into movement. In 2004, a consortium of major auto-makers — [BMW](https://en.wikipedia.org/wiki/BMW "BMW"), [General Motors](https://en.wikipedia.org/wiki/General_Motors "General Motors"), [Honda](https://en.wikipedia.org/wiki/Honda "Honda"), [Toyota](https://en.wikipedia.org/wiki/Toyota "Toyota") and [Volkswagen](https://en.wikipedia.org/wiki/Volkswagen "Volkswagen")/[Audi](https://en.wikipedia.org/wiki/Audi "Audi") — came up with *"Top Tier Detergent Gasoline Standard"* to [gasoline](https://en.wikipedia.org/wiki/Gasoline "Gasoline") brands in the US and Canada that meet their minimum standards for [detergent](https://en.wikipedia.org/wiki/Detergent "Detergent") content[\[18\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Top_Tier_Gasoline-18) and do not contain metallic additives. Top Tier gasoline contains higher levels of detergent additives in order to prevent the build-up of deposits (typically, on [fuel injector](https://en.wikipedia.org/wiki/Fuel_injector "Fuel injector") and [intake valve](https://en.wikipedia.org/wiki/Intake_valve "Intake valve")) known to reduce fuel economy and engine performance.[\[19\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-19) ### In microgravity \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=10 "Edit section: In microgravity")\] How fuel combusts affects how much energy is produced. The [National Aeronautics and Space Administration](https://en.wikipedia.org/wiki/National_Aeronautics_and_Space_Administration "National Aeronautics and Space Administration") (NASA) has investigated fuel consumption in [microgravity](https://en.wikipedia.org/wiki/Microgravity "Microgravity"). The common distribution of a flame under normal gravity conditions depends on [convection](https://en.wikipedia.org/wiki/Convection "Convection"), because soot tends to rise to the top of a flame, such as in a candle, making the flame yellow. In microgravity or [zero gravity](https://en.wikipedia.org/wiki/Zero_gravity "Zero gravity"), such as an environment in [outer space](https://en.wikipedia.org/wiki/Outer_space "Outer space"), convection no longer occurs, and the flame becomes [spherical](https://en.wikipedia.org/wiki/Sphere "Sphere"), with a tendency to become more blue and more efficient. There are several possible explanations for this difference, of which the most likely one given is the hypothesis that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs., National Aeronautics and Space Administration, April 2005. Experiments by NASA in microgravity reveal that [diffusion flames](https://en.wikipedia.org/wiki/Diffusion_flame "Diffusion flame") in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions.[LSP-1 experiment results](https://web.archive.org/web/20070312020123/http://microgravity.grc.nasa.gov/combustion/lsp/lsp1_results.htm), National Aeronautics and Space Administration, April 2005. [Premixed flames](https://en.wikipedia.org/wiki/Premixed_flame "Premixed flame") in microgravity burn at a much slower rate and more efficiently than even a candle on Earth, and last much longer.[\[20\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-20) ## See also \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=11 "Edit section: See also")\] - [![icon](https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Crystal_energy.svg/40px-Crystal_energy.svg.png)](https://en.wikipedia.org/wiki/File:Crystal_energy.svg)[Energy portal](https://en.wikipedia.org/wiki/Portal:Energy "Portal:Energy") - [Annual fuel utilization efficiency](https://en.wikipedia.org/wiki/Annual_fuel_utilization_efficiency "Annual fuel utilization efficiency") (AFUE) - [ACEA agreement](https://en.wikipedia.org/wiki/ACEA_agreement "ACEA agreement") - [Alternative propulsion](https://en.wikipedia.org/wiki/Alternative_propulsion "Alternative propulsion") - [Camless piston engine](https://en.wikipedia.org/wiki/Camless_piston_engine "Camless piston engine") - [Carbon dioxide equivalent](https://en.wikipedia.org/wiki/Carbon_dioxide_equivalent "Carbon dioxide equivalent") - [Corporate Average Fuel Economy](https://en.wikipedia.org/wiki/Corporate_Average_Fuel_Economy "Corporate Average Fuel Economy") (CAFE) - [EcoAuto](https://en.wikipedia.org/wiki/EcoAuto "EcoAuto") (in Canada) - [Efficient energy use](https://en.wikipedia.org/wiki/Efficient_energy_use "Efficient energy use") - [Emission standard](https://en.wikipedia.org/wiki/Emission_standard "Emission standard") - [Energy content of Biofuel](https://en.wikipedia.org/wiki/Energy_content_of_Biofuel "Energy content of Biofuel") - [Energy conservation](https://en.wikipedia.org/wiki/Energy_conservation "Energy conservation") - [Energy conversion efficiency](https://en.wikipedia.org/wiki/Energy_conversion_efficiency "Energy conversion efficiency") - [Energy density](https://en.wikipedia.org/wiki/Energy_density "Energy density") - [FF layout](https://en.wikipedia.org/wiki/FF_layout "FF layout") - [Front-wheel drive](https://en.wikipedia.org/wiki/Front-wheel_drive "Front-wheel drive") - [Fuel economy in aircraft](https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft "Fuel economy in aircraft") - [Fuel economy in automobiles](https://en.wikipedia.org/wiki/Fuel_economy_in_automobiles "Fuel economy in automobiles") - [Fuel economy maximising behaviors](https://en.wikipedia.org/wiki/Fuel_economy-maximizing_behaviors "Fuel economy-maximizing behaviors") - [Fuel efficiency in transportation](https://en.wikipedia.org/wiki/Fuel_efficiency_in_transportation "Fuel efficiency in transportation") - [Gas-guzzler](https://en.wikipedia.org/wiki/Gas-guzzler "Gas-guzzler") - [Heating value](https://en.wikipedia.org/wiki/Heating_value "Heating value") - [Jevons paradox](https://en.wikipedia.org/wiki/Jevons_paradox "Jevons paradox") - [Life cycle assessment](https://en.wikipedia.org/wiki/Life_cycle_assessment "Life cycle assessment") - [Low-rolling resistance tires](https://en.wikipedia.org/wiki/Low-rolling_resistance_tires "Low-rolling resistance tires") - [Miles per gallon gasoline equivalent](https://en.wikipedia.org/wiki/Miles_per_gallon_gasoline_equivalent "Miles per gallon gasoline equivalent") - [Marine fuel management](https://en.wikipedia.org/wiki/Marine_fuel_management "Marine fuel management") - [Twinjet](https://en.wikipedia.org/wiki/Twinjet "Twinjet") - [Variable valve timing](https://en.wikipedia.org/wiki/Variable_valve_timing "Variable valve timing") - [Unibody](https://en.wikipedia.org/wiki/Vehicle_frame#Unibody "Vehicle frame") - [Automobile costs](https://en.wikipedia.org/wiki/Automobile_costs "Automobile costs") - [Vehicle metrics](https://en.wikipedia.org/wiki/Vehicle_metrics "Vehicle metrics") ## References \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=12 "Edit section: References")\] 1. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-1)** ["Information on the fuel consumption of new cars"](https://web.archive.org/web/20190908124154/http://www.bilsweden.se/miljo-sakerhet/miljo/information-gallande-bransleforbrukning-for-nya-bilar). Archived from [the original](http://www.bilsweden.se/miljo-sakerhet/miljo/information-gallande-bransleforbrukning-for-nya-bilar) on 8 September 2019. Retrieved 7 November 2019. 2. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-2)** ["Learn More About the Fuel Economy Label for Gasoline Vehicles"](https://www.fueleconomy.gov/feg/label/learn-more-gasoline-label.shtml#fuel-consumption-rate). [Archived](https://web.archive.org/web/20130705143242/http://www.fueleconomy.gov/feg/label/learn-more-gasoline-label.shtml#fuel-consumption-rate) from the original on 2013-07-05. 3. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-3)** ["Simple tips and tricks to increase fuel efficiency of your car \| CarSangrah"](https://www.carsangrah.com/blog/simple-tips-tricks-enhance-fuel-efficiency-car). *CarSangrah*. 2018-06-07. Retrieved 2018-07-24. 4. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-4)** ["How Hybrids Work"](https://www.fueleconomy.gov/). [U.S. Department of Energy](https://en.wikipedia.org/wiki/U.S._Department_of_Energy "U.S. Department of Energy"). [Archived](https://web.archive.org/web/20150708093450/http://www.fueleconomy.gov/) from the original on 2015-07-08. Retrieved 2014-01-16. 5. ^ [***a***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-EPA_AutomotiveTrends_202212_5-0) [***b***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-EPA_AutomotiveTrends_202212_5-1) ["Highlights of the Automotive Trends Report"](https://www.epa.gov/automotive-trends/highlights-automotive-trends-report). *EPA.gov*. U.S. Environmental Protection Agency (EPA). 12 December 2022. [Archived](https://web.archive.org/web/20230902145941/https://www.epa.gov/automotive-trends/highlights-automotive-trends-report) from the original on 2 September 2023. 6. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-GlobalFuelEfficInit_202311_6-0)** Cazzola, Pierpaolo; Paoli, Leonardo; Teter, Jacob (November 2023). ["Trends in the Global Vehicle Fleet 2023 / Managing the SUV Shift and the EV Transition"](https://www.globalfueleconomy.org/media/792523/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf) (PDF). Global Fuel Economy Initiative (GFEI). p. 3. [doi](https://en.wikipedia.org/wiki/Doi_$identifier$ "Doi (identifier)"):[10\.7922/G2HM56SV](https://doi.org/10.7922%2FG2HM56SV). [Archived](https://web.archive.org/web/20231126092826/https://www.globalfueleconomy.org/media/792523/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf) (PDF) from the original on 26 November 2023. 7. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-7)** Calculated from heats of formation. Does not correspond exactly to the figure for MJ/L divided by density. 8. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-TEDB_8-0)** [Appendix B, Transportation Energy Data Book](http://www-cta.ornl.gov/data/Appendix_B.html) from the [Center for Transportation Analysis](https://en.wikipedia.org/wiki/Center_for_Transportation_Analysis "Center for Transportation Analysis") of the [Oak Ridge National Laboratory](https://en.wikipedia.org/wiki/Oak_Ridge_National_Laboratory "Oak Ridge National Laboratory") 9. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-9)** ["Efficiency"](http://www.merriam-webster.com/dictionary/efficiency). Retrieved 18 September 2016. 10. ^ [***a***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_fueleco_10-0) [***b***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_fueleco_10-1) [*Assessment of Fuel Economy Technologies for Light-duty Vehicles*](http://www.nap.edu/read/12924/chapter/4). The National Academies Press. 2011. [doi](https://en.wikipedia.org/wiki/Doi_$identifier$ "Doi (identifier)"):[10\.17226/12924](https://doi.org/10.17226%2F12924). [ISBN](https://en.wikipedia.org/wiki/ISBN_$identifier$ "ISBN (identifier)") [978-0-309-15607-3](https://en.wikipedia.org/wiki/Special:BookSources/978-0-309-15607-3 "Special:BookSources/978-0-309-15607-3") . Retrieved 18 September 2016. 11. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_DOEgloss_11-0)** ["Glossary of energy-related terms"](http://energy.gov/eere/energybasics/articles/glossary-energy-related-terms#E). [U.S. Department of Energy](https://en.wikipedia.org/wiki/U.S._Department_of_Energy "U.S. Department of Energy"). Retrieved 20 September 2016. 12. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-12)** Page, Walter Hines; Page, Arthur Wilson (1916). ["Man and His Machines"](https://books.google.com/books?id=lPAMVa7esS4C). *The World's Work*. Vol. XXXIII. Garden City, New York: Doubleday, Page & Co. 13. ^ [***a***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy-efficient_driving_Beusen_13-0) [***b***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy-efficient_driving_Beusen_13-1) Beusen; et al. (2009). ["Using on-board logging devices to study the long-term impact of an eco-driving course"](https://www.researchgate.net/publication/231614817). *Transportation Research D*. **14** (7): 514–520\. [Bibcode](https://en.wikipedia.org/wiki/Bibcode_$identifier$ "Bibcode (identifier)"):[2009TRPD...14..514B](https://ui.adsabs.harvard.edu/abs/2009TRPD...14..514B). [doi](https://en.wikipedia.org/wiki/Doi_$identifier$ "Doi (identifier)"):[10\.1016/j.trd.2009.05.009](https://doi.org/10.1016%2Fj.trd.2009.05.009). [Archived](https://web.archive.org/web/20131019115218/http://www.researchgate.net/publication/231614817_Using_on-board_logging_devices_to_study_the_long-term_impact_of_an_eco-driving_course?ev=prf_pub) from the original on 2013-10-19. 14. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-14)** ["20 Ways to Improve Your Fuel Efficiency and Save Money at the Pump"](http://car1.ca/blog/2016/08/02/20-ways-to-improve-your-fuel-efficiency-and-save-money-at-the-pump/). [Archived](https://web.archive.org/web/20160816132350/http://car1.ca/blog/2016/08/02/20-ways-to-improve-your-fuel-efficiency-and-save-money-at-the-pump/) from the original on 2016-08-16. 15. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy-efficient_driving_merriam-webster.com_15-0)** <http://www.merriam-webster.com/dictionary/hypermiling> Merriam Webster dictionary 16. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-16)** ["Staying Ahead Of The Curve: 3 Key Fleet Management Trends For 2023"](https://www.forbes.com/councils/forbestechcouncil/2023/04/18/staying-ahead-of-the-curve-3-key-fleet-management-trends-for-2023/). *Forbes*. April 18, 2023. Retrieved October 7, 2025. 17. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-17)** ["Rail 10 times better than air in London-Paris CO2 comparison - Transport & Environment"](http://www.transportenvironment.org/Article267.html). [Archived](https://web.archive.org/web/20070928024427/http://www.transportenvironment.org/Article267.html) from the original on 2007-09-28. 18. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Top_Tier_Gasoline_18-0)** [Top Tier Gasoline](http://www.toptiergas.com/retailers.html) [Archived](https://web.archive.org/web/20130815031514/http://www.toptiergas.com/retailers.html) 2013-08-15 at the [Wayback Machine](https://en.wikipedia.org/wiki/Wayback_Machine "Wayback Machine") 19. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-19)** ["Deposit Control Standards"](https://web.archive.org/web/20040806012056/http://www.toptiergas.com/deposit_control.html). Archived from [the original](http://www.toptiergas.com/deposit_control.html) on 2004-08-06. Retrieved 2012-10-19. 20. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-20)** [SOFBAL-2 experiment results](https://microgravity.grc.nasa.gov/combustion/lsp/lsp1_results.htm) [Archived](https://web.archive.org/web/20070312020123/http://microgravity.grc.nasa.gov/combustion/lsp/lsp1_results.htm) 2007-03-12 at the [Wayback Machine](https://en.wikipedia.org/wiki/Wayback_Machine "Wayback Machine"), National Aeronautics and Space Administration, April 2005. ## External links \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=13 "Edit section: External links")\] | | | |---|---| | ![](https://upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/40px-Edit-clear.svg.png) | This article's **use of [external links](https://en.wikipedia.org/wiki/Wikipedia:External_links "Wikipedia:External links") may not follow Wikipedia's policies or guidelines**. Please [improve this article](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit) by removing [excessive](https://en.wikipedia.org/wiki/Wikipedia:What_Wikipedia_is_not#Wikipedia_is_not_a_mirror_or_a_repository_of_links,_images,_or_media_files "Wikipedia:What Wikipedia is not") or [inappropriate](https://en.wikipedia.org/wiki/Wikipedia:External_links "Wikipedia:External links") external links, and converting useful links where appropriate into [footnote references](https://en.wikipedia.org/wiki/Wikipedia:Citing_sources "Wikipedia:Citing sources"). *(November 2023)* *([Learn how and when to remove this message](https://en.wikipedia.org/wiki/Help:Maintenance_template_removal "Help:Maintenance template removal"))* | - [US Government website on fuel economy](https://www.fueleconomy.gov/) - [UK DfT comparisons on road and rail](http://www.dft.gov.uk/stellent/groups/dft_railways/documents/page/dft_railways_611287.pdf) - [NASA Offers a \$1.5 Million Prize for a Fast and Fuel-Efficient Aircraft](http://apps1.eere.energy.gov/news/news_detail.cfm/news_id=12694) [Archived](https://web.archive.org/web/20160303200449/http://apps1.eere.energy.gov/news/news_detail.cfm/news_id=12694) 2016-03-03 at the [Wayback Machine](https://en.wikipedia.org/wiki/Wayback_Machine "Wayback Machine") - [Car Fuel Consumption Official Figures](http://www.carfuelconsumption.com/) - [Spritmonitor.de "the most fuel efficient cars" - Database of thousands of (mostly German) car owners' actual fuel consumption figures](https://www.spritmonitor.de/de/die_sparsamsten_autos.html) (cf. [Spritmonitor](https://en.wikipedia.org/wiki/Spritmonitor "Spritmonitor")) - [Searchable fuel economy data from the EPA - United States Environmental Protection Agency](https://web.archive.org/web/20131029195658/http://fueleconomy.carconsumption.com/) - [penghemat bbm - Alat penghemat bbm](http://www.xpower-ionizer.com/) - [Ny Times: A Road Test of Alternative Fuel Visions](https://www.nytimes.com/2014/11/18/science/earth/hydrogen-cars-join-electric-models-in-showrooms.html) | [v](https://en.wikipedia.org/wiki/Template:Public_infrastructure_topics "Template:Public infrastructure topics") [t](https://en.wikipedia.org/wiki/Template_talk:Public_infrastructure_topics "Template talk:Public infrastructure topics") [e](https://en.wikipedia.org/wiki/Special:EditPage/Template:Public_infrastructure_topics "Special:EditPage/Template:Public infrastructure topics")[Public infrastructure](https://en.wikipedia.org/wiki/Public_infrastructure "Public infrastructure") | | |---|---| | [Assets](https://en.wikipedia.org/wiki/Fixed_asset "Fixed asset") and facilities | [Airports](https://en.wikipedia.org/wiki/Airport "Airport") [Bridges](https://en.wikipedia.org/wiki/Bridge "Bridge") [Broadband](https://en.wikipedia.org/wiki/Broadband "Broadband") [Canals](https://en.wikipedia.org/wiki/Canal "Canal") [Critical infrastructure](https://en.wikipedia.org/wiki/Critical_infrastructure "Critical infrastructure") [Dams](https://en.wikipedia.org/wiki/Dam "Dam") [Electricity generation](https://en.wikipedia.org/wiki/Electricity_generation "Electricity generation") [Energy development](https://en.wikipedia.org/wiki/Energy_development "Energy development") [Hazardous waste](https://en.wikipedia.org/wiki/Hazardous_waste "Hazardous waste") [Hospitals](https://en.wikipedia.org/wiki/Hospital "Hospital") [Levees](https://en.wikipedia.org/wiki/Levee "Levee") [Lighthouses](https://en.wikipedia.org/wiki/Lighthouse "Lighthouse") [Municipal solid waste](https://en.wikipedia.org/wiki/Municipal_solid_waste "Municipal solid waste") [Parks](https://en.wikipedia.org/wiki/Park "Park") [Ports](https://en.wikipedia.org/wiki/Port "Port") [Public housing](https://en.wikipedia.org/wiki/Public_housing "Public housing") [Public spaces](https://en.wikipedia.org/wiki/Public_space "Public space") [Public transport](https://en.wikipedia.org/wiki/Public_transport "Public transport") [Public utilities](https://en.wikipedia.org/wiki/Public_utility "Public utility") [Public works](https://en.wikipedia.org/wiki/Public_works "Public works") [Rail transport](https://en.wikipedia.org/wiki/Rail_transport "Rail transport") [Roads](https://en.wikipedia.org/wiki/Road "Road") [Sewage](https://en.wikipedia.org/wiki/Sewage "Sewage") [State schools](https://en.wikipedia.org/wiki/State_school "State school") [Telecommunications](https://en.wikipedia.org/wiki/Telecommunications "Telecommunications") [Town square](https://en.wikipedia.org/wiki/Town_square "Town square") [Wastewater treatment](https://en.wikipedia.org/wiki/Wastewater_treatment "Wastewater treatment") [Water supply network](https://en.wikipedia.org/wiki/Water_supply_network "Water supply network") [Wind power](https://en.wikipedia.org/wiki/Wind_power "Wind power") | | Concepts | [Appropriation](https://en.wikipedia.org/wiki/Appropriation_$law$ "Appropriation (law)") [Infrastructure asset management](https://en.wikipedia.org/wiki/Infrastructure_asset_management "Infrastructure asset management") [Build–operate–transfer](https://en.wikipedia.org/wiki/Build%E2%80%93operate%E2%80%93transfer "Build–operate–transfer") [Design–build](https://en.wikipedia.org/wiki/Design%E2%80%93build "Design–build") [Earmark](https://en.wikipedia.org/wiki/Earmark_$politics$ "Earmark (politics)") [Engineering contracts](https://en.wikipedia.org/wiki/Infrastructure#Engineering "Infrastructure") [Externality](https://en.wikipedia.org/wiki/Externality "Externality") [Fixed cost](https://en.wikipedia.org/wiki/Fixed_cost "Fixed cost") [Government debt](https://en.wikipedia.org/wiki/Government_debt "Government debt") [Infrastructure bond](https://en.wikipedia.org/wiki/Infrastructure_bond "Infrastructure bond") [Life-cycle assessment](https://en.wikipedia.org/wiki/Life-cycle_assessment "Life-cycle assessment") [Lindahl tax](https://en.wikipedia.org/wiki/Lindahl_tax "Lindahl tax") [Maintenance, repair, and operations](https://en.wikipedia.org/wiki/Maintenance,_repair,_and_operations "Maintenance, repair, and operations") [Natural monopoly](https://en.wikipedia.org/wiki/Natural_monopoly "Natural monopoly") [Property tax](https://en.wikipedia.org/wiki/Property_tax "Property tax") [Public capital](https://en.wikipedia.org/wiki/Public_capital "Public capital") [Public finance](https://en.wikipedia.org/wiki/Public_finance "Public finance") [Public good](https://en.wikipedia.org/wiki/Public_good_$economics$ "Public good (economics)") [Public sector](https://en.wikipedia.org/wiki/Public_sector "Public sector") [Public–private partnership](https://en.wikipedia.org/wiki/Public%E2%80%93private_partnership "Public–private partnership") [Renovation](https://en.wikipedia.org/wiki/Renovation "Renovation") [Spillover](https://en.wikipedia.org/wiki/Spillover_$economics$ "Spillover (economics)") [Supply chain](https://en.wikipedia.org/wiki/Supply_chain "Supply chain") [Taxation](https://en.wikipedia.org/wiki/Tax "Tax") [Upgrade](https://en.wikipedia.org/wiki/Upgrade "Upgrade") | | Issues and ideas | [Air traffic control](https://en.wikipedia.org/wiki/Air_traffic_control "Air traffic control") [Brownfield land](https://en.wikipedia.org/wiki/Brownfield_land "Brownfield land") [Bus rapid transit](https://en.wikipedia.org/wiki/Bus_rapid_transit "Bus rapid transit") [Carbon footprint](https://en.wikipedia.org/wiki/Carbon_footprint "Carbon footprint") [Congestion pricing](https://en.wikipedia.org/wiki/Congestion_pricing "Congestion pricing") [Containerization](https://en.wikipedia.org/wiki/Containerization "Containerization") [Ethanol fuel](https://en.wikipedia.org/wiki/Ethanol_fuel "Ethanol fuel") [Fuel efficiency]() [Fuel tax](https://en.wikipedia.org/wiki/Fuel_tax "Fuel tax") [Groundwater](https://en.wikipedia.org/wiki/Groundwater "Groundwater") [High-speed rail](https://en.wikipedia.org/wiki/High-speed_rail "High-speed rail") [Hybrid vehicles](https://en.wikipedia.org/wiki/Hybrid_vehicle "Hybrid vehicle") [Land-use planning](https://en.wikipedia.org/wiki/Land-use_planning "Land-use planning") [Mobile data terminal](https://en.wikipedia.org/wiki/Mobile_data_terminal "Mobile data terminal") [Pork barrel](https://en.wikipedia.org/wiki/Pork_barrel "Pork barrel") [Recycling](https://en.wikipedia.org/wiki/Recycling "Recycling") [Renewable resources](https://en.wikipedia.org/wiki/Renewable_resource "Renewable resource") [Reverse osmosis](https://en.wikipedia.org/wiki/Reverse_osmosis "Reverse osmosis") [Smart grid](https://en.wikipedia.org/wiki/Smart_grid "Smart grid") [Smart growth](https://en.wikipedia.org/wiki/Smart_growth "Smart growth") [Stormwater](https://en.wikipedia.org/wiki/Stormwater "Stormwater") [Sustainable urban infrastructure](https://en.wikipedia.org/wiki/Sustainable_urban_infrastructure "Sustainable urban infrastructure") [Traffic congestion](https://en.wikipedia.org/wiki/Traffic_congestion "Traffic congestion") [Transit-oriented development](https://en.wikipedia.org/wiki/Transit-oriented_development "Transit-oriented development") [Urban sprawl](https://en.wikipedia.org/wiki/Urban_sprawl "Urban sprawl") [Waste-to-energy](https://en.wikipedia.org/wiki/Waste-to-energy "Waste-to-energy") [Weatherization](https://en.wikipedia.org/wiki/Weatherization "Weatherization") [Wireless](https://en.wikipedia.org/wiki/Wireless "Wireless") | | Fields of study | [Architecture](https://en.wikipedia.org/wiki/Architecture "Architecture") [Civil engineering](https://en.wikipedia.org/wiki/Civil_engineering "Civil engineering") [Electrical engineering](https://en.wikipedia.org/wiki/Electrical_engineering "Electrical engineering") [Mechanical engineering](https://en.wikipedia.org/wiki/Mechanical_engineering "Mechanical engineering") [Public economics](https://en.wikipedia.org/wiki/Public_economics "Public economics") [Public policy](https://en.wikipedia.org/wiki/Public_policy "Public policy") [Urban planning](https://en.wikipedia.org/wiki/Urban_planning "Urban planning") | | Examples | [Akashi Kaikyō Bridge](https://en.wikipedia.org/wiki/Akashi_Kaiky%C5%8D_Bridge "Akashi Kaikyō Bridge") [Autobahn](https://en.wikipedia.org/wiki/Autobahn "Autobahn") [Brooklyn Bridge](https://en.wikipedia.org/wiki/Brooklyn_Bridge "Brooklyn Bridge") [Bus rapid transit systems](https://en.wikipedia.org/wiki/List_of_bus_rapid_transit_systems "List of bus rapid transit systems") [Channel Tunnel](https://en.wikipedia.org/wiki/Channel_Tunnel "Channel Tunnel") [Controlled-access highway systems](https://en.wikipedia.org/wiki/List_of_controlled-access_highway_systems "List of controlled-access highway systems") [Electric power transmission](https://en.wikipedia.org/wiki/Electric_power_transmission#Overhead_transmission "Electric power transmission") [High-speed trains](https://en.wikipedia.org/wiki/List_of_high-speed_trains "List of high-speed trains") [Hong Kong International Airport](https://en.wikipedia.org/wiki/Hong_Kong_International_Airport "Hong Kong International Airport") [Hoover Dam](https://en.wikipedia.org/wiki/Hoover_Dam "Hoover Dam") [Humber Bridge](https://en.wikipedia.org/wiki/Humber_Bridge "Humber Bridge") [Kansai International Airport](https://en.wikipedia.org/wiki/Kansai_International_Airport "Kansai International Airport") [Millau Viaduct](https://en.wikipedia.org/wiki/Millau_Viaduct "Millau Viaduct") [Nuclear power](https://en.wikipedia.org/wiki/Nuclear_power_by_country "Nuclear power by country") [Offshore wind farms](https://en.wikipedia.org/wiki/List_of_offshore_wind_farms "List of offshore wind farms") [Panama Canal](https://en.wikipedia.org/wiki/Panama_Canal "Panama Canal") [Port of Shanghai](https://en.wikipedia.org/wiki/Port_of_Shanghai "Port of Shanghai") [San Francisco–Oakland Bay Bridge](https://en.wikipedia.org/wiki/San_Francisco%E2%80%93Oakland_Bay_Bridge "San Francisco–Oakland Bay Bridge") [Suez Canal](https://en.wikipedia.org/wiki/Suez_Canal "Suez Canal") [Solar power](https://en.wikipedia.org/wiki/Solar_power_by_country "Solar power by country") [Three Gorges Dam](https://en.wikipedia.org/wiki/Three_Gorges_Dam "Three Gorges Dam") [Trans-Alaska pipeline](https://en.wikipedia.org/wiki/Trans-Alaska_Pipeline_System "Trans-Alaska Pipeline System") [Transcontinental railroads](https://en.wikipedia.org/wiki/Transcontinental_railroad "Transcontinental railroad") | ![](https://en.wikipedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=1) Retrieved from 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From Wikipedia, the free encyclopedia **Fuel efficiency** (or **fuel economy**) is a form of [thermal efficiency](https://en.wikipedia.org/wiki/Thermal_efficiency "Thermal efficiency"), meaning the [ratio](https://en.wikipedia.org/wiki/Ratio "Ratio") of effort to result of a process that converts [chemical](https://en.wikipedia.org/wiki/Chemical_energy "Chemical energy") [potential energy](https://en.wikipedia.org/wiki/Potential_energy "Potential energy") contained in a carrier ([fuel](https://en.wikipedia.org/wiki/Fuel "Fuel")) into kinetic energy or [work](https://en.wikipedia.org/wiki/Mechanical_work "Mechanical work"). Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous [energy profile](https://en.wikipedia.org/wiki/Energy_profile "Energy profile"). Non-transportation applications, such as [industry](https://en.wikipedia.org/wiki/Industrial_sector "Industrial sector"), benefit from increased fuel efficiency, especially [fossil fuel power plants](https://en.wikipedia.org/wiki/Fossil_fuel_power_plant "Fossil fuel power plant") or industries dealing with [combustion](https://en.wikipedia.org/wiki/Combustion "Combustion"), such as [ammonia](https://en.wikipedia.org/wiki/Ammonia "Ammonia") production during the [Haber process](https://en.wikipedia.org/wiki/Haber_process "Haber process"). In the context of [transport](https://en.wikipedia.org/wiki/Transport "Transport"), fuel economy is the [energy efficiency](https://en.wikipedia.org/wiki/Energy_efficiency_in_transportation "Energy efficiency in transportation") of a particular vehicle, given as a [ratio](https://en.wikipedia.org/wiki/Ratio "Ratio") of distance traveled per unit of [fuel](https://en.wikipedia.org/wiki/Motor_fuel "Motor fuel") consumed. It is dependent on several factors including [engine efficiency](https://en.wikipedia.org/wiki/Engine_efficiency "Engine efficiency"), [transmission](https://en.wikipedia.org/wiki/Transmission_$mechanics$ "Transmission (mechanics)") design, and [tire](https://en.wikipedia.org/wiki/Tire "Tire") design. In most countries, using the [metric system](https://en.wikipedia.org/wiki/Metric_system "Metric system"), fuel economy is stated as "fuel consumption" in [liters](https://en.wikipedia.org/wiki/Liter "Liter") per 100 [kilometers](https://en.wikipedia.org/wiki/Kilometers "Kilometers") (L/100 km) or kilometers per liter (km/L or kmpl). In a number of countries still using other systems, fuel economy is expressed in [miles](https://en.wikipedia.org/wiki/Mile "Mile") per [gallon](https://en.wikipedia.org/wiki/Gallon "Gallon") (mpg), for example in the US and usually also in the UK ([imperial](https://en.wikipedia.org/wiki/Imperial_units "Imperial units") gallon); there is sometimes confusion as the imperial gallon is 20% larger than the US gallon so that mpg values are not directly comparable. Traditionally, litres per [mil](https://en.wikipedia.org/wiki/Scandinavian_mile "Scandinavian mile") were used in [Norway](https://en.wikipedia.org/wiki/Norway "Norway") and [Sweden](https://en.wikipedia.org/wiki/Sweden "Sweden"), but both have aligned to the EU standard of L/100 km.[\[1\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-1) Fuel consumption is a more accurate measure of a vehicle's performance because it is a linear relationship while fuel economy leads to distortions in efficiency improvements.[\[2\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-2) Weight-specific efficiency (efficiency per unit weight) may be stated for [freight](https://en.wikipedia.org/wiki/Freight "Freight"), and passenger-specific efficiency (vehicle efficiency per passenger) for passenger vehicles. Fuel efficiency is dependent on many parameters of a vehicle, including its [engine](https://en.wikipedia.org/wiki/Engine "Engine") parameters, [aerodynamic drag](https://en.wikipedia.org/wiki/Drag_$physics$ "Drag (physics)"), weight, AC usage, fuel and [rolling resistance](https://en.wikipedia.org/wiki/Rolling_resistance "Rolling resistance"). There have been advances in all areas of vehicle design in recent decades. Fuel efficiency of vehicles can also be improved by careful maintenance and driving habits.[\[3\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-3) [Hybrid vehicles](https://en.wikipedia.org/wiki/Hybrid_vehicles "Hybrid vehicles") use two or more power sources for propulsion. In many designs, a small combustion engine is combined with electric motors. Kinetic energy which would otherwise be lost to heat during braking is recaptured as electrical power to improve fuel efficiency. The larger batteries in these vehicles power the [car's electronics](https://en.wikipedia.org/wiki/Automotive_electronics "Automotive electronics"), allowing the engine to shut off and avoid prolonged [idling](https://en.wikipedia.org/wiki/Start-stop_system "Start-stop system").[\[4\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-4) [![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/90/1975-_US_vehicle_production_share%2C_by_vehicle_type.svg/250px-1975-_US_vehicle_production_share%2C_by_vehicle_type.svg.png)](https://en.wikipedia.org/wiki/File:1975-_US_vehicle_production_share,_by_vehicle_type.svg) Trucks' share of US vehicles produced, has tripled since 1975. Though vehicle fuel efficiency has increased within each category, the overall trend toward less efficient types of vehicles has offset some of the benefits of greater fuel economy and reduction in carbon dioxide emissions.[\[5\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-EPA_AutomotiveTrends_202212-5) Without the shift towards SUVs, energy use per unit distance could have fallen 30% more than it did from 2010 to 2022.[\[6\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-GlobalFuelEfficInit_202311-6) Fleet efficiency describes the average efficiency of a population of vehicles. Technological advances in efficiency may be offset by a change in buying habits with a propensity to heavier vehicles that are less fuel-efficient.[\[5\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-EPA_AutomotiveTrends_202212-5) ## Energy efficiency terminology \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=3 "Edit section: Energy efficiency terminology")\] [Energy efficiency](https://en.wikipedia.org/wiki/Energy_efficiency_$physics$ "Energy efficiency (physics)") is similar to fuel efficiency but the input is usually in units of energy such as [megajoules](https://en.wikipedia.org/wiki/Megajoules "Megajoules") (MJ), [kilowatt-hours](https://en.wikipedia.org/wiki/Kilowatt-hours "Kilowatt-hours") (kW·h), kilocalories (kcal) or [British thermal units](https://en.wikipedia.org/wiki/British_thermal_units "British thermal units") (BTU). The inverse of "energy efficiency" is "[energy intensity](https://en.wikipedia.org/wiki/Energy_intensity "Energy intensity")", or the amount of input energy required for a unit of output such as MJ/passenger-km (of passenger transport), BTU/ton-mile or kJ/t-km (of freight transport), GJ/t (for production of steel and other materials), BTU/(kW·h) (for electricity generation), or litres/100 km (of vehicle travel). Litres per 100 km is also a measure of "energy intensity" where the input is measured by the amount of fuel and the output is measured by the [distance](https://en.wikipedia.org/wiki/Distance "Distance") travelled. For example: [Fuel economy in automobiles](https://en.wikipedia.org/wiki/Fuel_economy_in_automobiles "Fuel economy in automobiles"). Given a heat value of a fuel, it would be trivial to convert from fuel units (such as litres of gasoline) to energy units (such as MJ) and conversely. But there are two problems with comparisons made using energy units: - There are two different heat values for any hydrogen-containing fuel which can differ by several percent (see below). - When comparing transportation energy costs, a [kilowatt hour](https://en.wikipedia.org/wiki/Kilowatt_hour "Kilowatt hour") of electric energy may require an amount of fuel with heating value of 2 or 3 kilowatt hours to produce it. ## Energy content of fuel \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=4 "Edit section: Energy content of fuel")\] The specific [energy content](https://en.wikipedia.org/wiki/Energy_content "Energy content") of a fuel is the heat energy obtained when a certain quantity is burned (such as a gallon, litre, kilogram). It is sometimes called the [heat of combustion](https://en.wikipedia.org/wiki/Heat_of_combustion "Heat of combustion"). There exists two different values of [specific heat](https://en.wikipedia.org/wiki/Specific_heat "Specific heat") energy for the same batch of fuel. One is the high (or gross) heat of combustion and the other is the low (or net) heat of combustion. The high value is obtained when, after the combustion, the water in the exhaust is in liquid form. For the low value, the exhaust has all the water in vapor form (steam). Since water vapor gives up heat energy when it changes from vapor to liquid, the liquid water value is larger since it includes the [latent heat](https://en.wikipedia.org/wiki/Latent_heat "Latent heat") of vaporization of water. The difference between the high and low values is significant, about 8 or 9%. This accounts for most of the apparent discrepancy in the heat value of gasoline. In the U.S. (and the table) the high heat values have traditionally been used, but in many other countries, the low heat values are commonly used. | Fuel type | MJ/L | MJ/kg | [BTU](https://en.wikipedia.org/wiki/British_thermal_unit "British thermal unit")/[imp gal](https://en.wikipedia.org/wiki/Gallon "Gallon") | BTU/[US gal](https://en.wikipedia.org/wiki/US_gallon "US gallon") | [Research octane number (RON)](https://en.wikipedia.org/wiki/Octane_rating "Octane rating") | |---|---|---|---|---|---| | Regular [gasoline](https://en.wikipedia.org/wiki/Gasoline "Gasoline")/petrol | 34\.8 | ~47 | 150,100 | 125,000 | Min. 91 | | Premium [gasoline](https://en.wikipedia.org/wiki/Gasoline "Gasoline")/petrol | | ~46 | | | Min. 95 | | [Autogas](https://en.wikipedia.org/wiki/Autogas "Autogas") ([LPG](https://en.wikipedia.org/wiki/Liquefied_petroleum_gas "Liquefied petroleum gas")) (60% [propane](https://en.wikipedia.org/wiki/Propane "Propane") and 40% [butane](https://en.wikipedia.org/wiki/Butane "Butane")) | 25\.5–28.7 | ~51 | | | 108–110 | | [Ethanol](https://en.wikipedia.org/wiki/Ethanol_fuel "Ethanol fuel") | 23\.5 | 31\.1[\[7\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-7) | 101,600 | 84,600 | 129 | | [Methanol](https://en.wikipedia.org/wiki/Methanol "Methanol") | 17\.9 | 19\.9 | 77,600 | 64,600 | 123 | | [Gasohol](https://en.wikipedia.org/wiki/Alcohol_fuel "Alcohol fuel") (10% ethanol and 90% gasoline) | 33\.7 | ~45 | 145,200 | 121,000 | 93/94 | | [E85](https://en.wikipedia.org/wiki/E85 "E85") (85% ethanol and 15% gasoline) | 25\.2 | ~33 | 108,878 | 90,660 | 100–105 | | [Diesel](https://en.wikipedia.org/wiki/Diesel_fuel "Diesel fuel") | 38\.6 | ~48 | 166,600 | 138,700 | [N/A (see cetane)](https://en.wikipedia.org/wiki/Cetane_number "Cetane number") | | [Biodiesel](https://en.wikipedia.org/wiki/Biodiesel "Biodiesel") | 35\.1 | 39\.9 | 151,600 | 126,200 | [N/A (see cetane)](https://en.wikipedia.org/wiki/Cetane_number "Cetane number") | | [Vegetable oil](https://en.wikipedia.org/wiki/WVO "WVO") (using 9.00 kcal/g) | 34\.3 | 37\.7 | 147,894 | 123,143 | | | [Aviation gasoline](https://en.wikipedia.org/wiki/Aviation_gasoline "Aviation gasoline") | 33\.5 | 46\.8 | 144,400 | 120,200 | 80-145 | | [Jet fuel](https://en.wikipedia.org/wiki/Jet_fuel "Jet fuel"), naphtha | 35\.5 | 46\.6 | 153,100 | 127,500 | N/A to turbine engines | | [Jet fuel](https://en.wikipedia.org/wiki/Jet_fuel "Jet fuel"), kerosene | 37\.6 | ~47 | 162,100 | 135,000 | N/A to turbine engines | | [Liquefied natural gas](https://en.wikipedia.org/wiki/Liquefied_natural_gas "Liquefied natural gas") | 25\.3 | ~55 | 109,000 | 90,800 | | | [Liquid hydrogen](https://en.wikipedia.org/wiki/Liquid_hydrogen "Liquid hydrogen") | 9\.3 | ~130 | 40,467 | 33,696 | | [\[8\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-TEDB-8) Neither the gross heat of combustion nor the net heat of combustion gives the theoretical amount of mechanical energy (work) that can be obtained from the reaction. (This is given by the change in [Gibbs free energy](https://en.wikipedia.org/wiki/Gibbs_free_energy "Gibbs free energy"), and is around 45.7 MJ/kg for gasoline.) The actual amount of mechanical work obtained from fuel (the inverse of the [specific fuel consumption](https://en.wikipedia.org/wiki/Brake-specific_fuel_consumption "Brake-specific fuel consumption")) depends on the engine. A figure of 17.6 MJ/kg is possible with a gasoline engine, and 19.1 MJ/kg for a diesel engine. See [Brake-specific fuel consumption](https://en.wikipedia.org/wiki/Brake-specific_fuel_consumption "Brake-specific fuel consumption") for more information.\[*[clarification needed](https://en.wikipedia.org/wiki/Wikipedia:Please_clarify "Wikipedia:Please clarify")*\] The [energy efficiency in transport](https://en.wikipedia.org/wiki/Energy_efficiency_in_transport "Energy efficiency in transport") is the useful travelled [distance](https://en.wikipedia.org/wiki/Distance "Distance"), of passengers, goods or any type of load; divided by the total [energy](https://en.wikipedia.org/wiki/Energy "Energy") put into the transport [propulsion](https://en.wikipedia.org/wiki/Propulsion "Propulsion") means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in [liquid fuels](https://en.wikipedia.org/wiki/Liquid_fuel "Liquid fuel"), [electrical energy](https://en.wikipedia.org/wiki/Electrical_energy "Electrical energy") or [food energy](https://en.wikipedia.org/wiki/Food_energy "Food energy").[\[9\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-9)[\[10\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_fueleco-10) The [energy efficiency](https://en.wikipedia.org/wiki/Efficient_energy_use "Efficient energy use") is also occasionally known as [energy intensity](https://en.wikipedia.org/wiki/Energy_intensity "Energy intensity").[\[11\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_DOEgloss-11) The [inverse](https://en.wikipedia.org/wiki/Multiplicative_inverse "Multiplicative inverse") of the energy efficiency in transport is the energy consumption in transport. Energy efficiency in transport is often described in terms of [fuel consumption](https://en.wikipedia.org/wiki/Fuel_consumption "Fuel consumption"), fuel consumption being the reciprocal of fuel economy.[\[10\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy_efficiency_in_transport_fueleco-10) Nonetheless, fuel consumption is linked with a means of propulsion which uses [liquid fuels](https://en.wikipedia.org/wiki/Liquid_fuel "Liquid fuel"), whilst energy efficiency is applicable to any sort of propulsion. To avoid said confusion, and to be able to compare the energy efficiency in any type of vehicle, experts tend to measure the energy in the [International System of Units](https://en.wikipedia.org/wiki/International_System_of_Units "International System of Units"), i.e., [joules](https://en.wikipedia.org/wiki/Joule "Joule"). Therefore, in the International System of Units, the energy efficiency in transport is measured in terms of metre per joule, or m/J, while the energy consumption in transport is measured in terms of joules per metre, or J/m. The more efficient the vehicle, the more metres it covers with one joule (more efficiency), or the fewer joules it uses to travel over one metre (less consumption). The [energy efficiency](https://en.wikipedia.org/wiki/Efficient_energy_use "Efficient energy use") in transport largely varies by means of transport. Different types of [transport](https://en.wikipedia.org/wiki/Transportation "Transportation") range from some hundred [kilojoules](https://en.wikipedia.org/wiki/Joule "Joule") per kilometre (kJ/km) for a [bicycle](https://en.wikipedia.org/wiki/Bicycle "Bicycle") to tens of megajoules per kilometre (MJ/km) for a [helicopter](https://en.wikipedia.org/wiki/Helicopter "Helicopter"). Via type of fuel used and rate of fuel consumption, energy efficiency is also often related to operating cost (\$/km) and environmental emissions (e.g. CO2/km). ### Fuel efficiency of motor vehicles \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=6 "Edit section: Fuel efficiency of motor vehicles")\] [![](https://upload.wikimedia.org/wikipedia/commons/thumb/3/38/CAFE_performance.svg/250px-CAFE_performance.svg.png)](https://en.wikipedia.org/wiki/File:CAFE_performance.svg) New light-duty vehicle fuel economy by vehicle type from vehicle manufacturers in the United States, in miles per gallon (1975 - 2019) [![](https://upload.wikimedia.org/wikipedia/commons/thumb/3/35/2006_Honda_Airwave_fuel_efficiency_meter.jpg/250px-2006_Honda_Airwave_fuel_efficiency_meter.jpg)](https://en.wikipedia.org/wiki/File:2006_Honda_Airwave_fuel_efficiency_meter.jpg) Fuel consumption monitor from a 2006 [Honda Airwave](https://en.wikipedia.org/wiki/Honda_Airwave "Honda Airwave"). The displayed fuel economy is 18.1 km/L (5.5 L/100 km; 43 mpg‑US). [![](https://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Fuel_Economy%2C_1916.jpg/250px-Fuel_Economy%2C_1916.jpg)](https://en.wikipedia.org/wiki/File:Fuel_Economy,_1916.jpg) A [Briggs and Stratton Flyer](https://en.wikipedia.org/wiki/Briggs_and_Stratton_Flyer "Briggs and Stratton Flyer") from 1916. Originally an experiment in creating a fuel-saving automobile in the United States, the vehicle weighed only 135 lb (61.2 kg) and was an adaptation of a small gasoline engine originally designed to power a bicycle.[\[12\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-12) The [fuel economy](https://en.wikipedia.org/wiki/Fuel_economy_in_automobiles "Fuel economy in automobiles") or fuel efficiency of an [automobile](https://en.wikipedia.org/wiki/Car "Car") relates to the [distance traveled](https://en.wikipedia.org/wiki/Distance_traveled "Distance traveled") by a vehicle and the amount of [fuel](https://en.wikipedia.org/wiki/Fuel "Fuel") consumed. It can be expressed in terms of the volume of fuel to travel a given distance, such as in litres per 100 kilometres (L/100 km), or through its inverse, the distance traveled per unit volume of fuel consumed, as in kilometres per litre (km/L) or miles per gallon (mpg). Since fuel economy of vehicles is a significant factor in [air pollution](https://en.wikipedia.org/wiki/Air_pollution "Air pollution"), the importation of [motor fuel](https://en.wikipedia.org/wiki/Motor_fuel "Motor fuel") can be a large part of a nation's [foreign trade](https://en.wikipedia.org/wiki/Foreign_trade "Foreign trade") and consumers frequently undervalue fuel efficiency, many countries impose requirements for fuel economy. Different methods are used to approximate the actual performance of the vehicle. The energy in fuel is required to overcome various losses ([wind resistance](https://en.wikipedia.org/wiki/Wind_resistance "Wind resistance"), [tire drag](https://en.wikipedia.org/wiki/Tire_drag "Tire drag"), and others) encountered while propelling the vehicle, and in providing power to vehicle systems such as ignition or air conditioning. Various strategies can be employed to reduce losses at each of the conversions between the [chemical energy](https://en.wikipedia.org/wiki/Chemical_energy "Chemical energy") in the fuel and the [kinetic energy](https://en.wikipedia.org/wiki/Kinetic_energy "Kinetic energy") of the vehicle. Driver behavior can affect fuel economy; maneuvers such as sudden acceleration and heavy [braking](https://en.wikipedia.org/wiki/Braking "Braking") waste energy. [Electric cars](https://en.wikipedia.org/wiki/Electric_car "Electric car") use [kilowatt-hours](https://en.wikipedia.org/wiki/Kilowatt-hours "Kilowatt-hours") of electricity per 100 kilometres (kWh/100km); in the U.S., an equivalence measure, such as [miles per gallon gasoline equivalent](https://en.wikipedia.org/wiki/Miles_per_gallon_gasoline_equivalent "Miles per gallon gasoline equivalent") (US gallon) has been created to attempt to compare them. [Energy-efficient driving](https://en.wikipedia.org/wiki/Energy-efficient_driving "Energy-efficient driving") techniques are used by drivers who wish to reduce their fuel consumption, and thus maximize fuel efficiency. Many drivers have the potential to improve their fuel efficiency significantly.[\[13\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy-efficient_driving_Beusen-13) Simple things such as keeping tires properly inflated, having a vehicle well-maintained and avoiding idling can dramatically improve fuel efficiency.[\[14\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-14) Careful use of acceleration and deceleration and especially limiting use of high speeds helps efficiency. The use of multiple such techniques is called "[hypermiling](https://en.wikipedia.org/wiki/Hypermiling "Hypermiling")".[\[15\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy-efficient_driving_merriam-webster.com-15) While these techniques can be applied by any driver, energy-efficient driving (often called "eco-driving") has become a major focus of modern [fleet management](https://en.wikipedia.org/wiki/Fleet_management "Fleet management"). As a key part of [fleet digitalization](https://en.wikipedia.org/wiki/Fleet_digitalization "Fleet digitalization"), companies use [telematics](https://en.wikipedia.org/wiki/Telematics "Telematics") to automatically monitor and manage fuel economy. A [fleet telematics system](https://en.wikipedia.org/wiki/Fleet_telematics_system "Fleet telematics system") collects data on behaviors that waste fuel, such as harsh acceleration, speeding, and idling. This information is then used in [driver scoring](https://en.wikipedia.org/wiki/Driver_scoring "Driver scoring") applications to identify and coach drivers.[\[13\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Energy-efficient_driving_Beusen-13) This is often combined with dedicated [fuel-management systems](https://en.wikipedia.org/wiki/Fuel-management_systems "Fuel-management systems") that use high-precision [fuel level sensors](https://en.wikipedia.org/w/index.php?title=Fuel_level_sensor&action=edit&redlink=1 "Fuel level sensor (page does not exist)") to get exact fuel consumption data and prevent [gasoline theft](https://en.wikipedia.org/wiki/Gasoline_theft "Gasoline theft").[\[16\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-16) Simple fuel-efficiency techniques can result in reduction in fuel consumption without resorting to radical fuel-saving techniques that can be unlawful and dangerous, such as tailgating larger vehicles. ## Advanced technology \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=8 "Edit section: Advanced technology")\] The most efficient machines for converting energy to rotary motion are electric motors, as used in [electric vehicles](https://en.wikipedia.org/wiki/Electric_vehicles "Electric vehicles"). However, electricity is not a primary energy source so the efficiency of the electricity production has also to be taken into account. [Railway](https://en.wikipedia.org/wiki/Railway "Railway") trains can be powered using electricity, delivered through an additional running rail, overhead [catenary](https://en.wikipedia.org/wiki/Overhead_lines "Overhead lines") system or by on-board generators used in [diesel-electric](https://en.wikipedia.org/wiki/Diesel-electric_transmission "Diesel-electric transmission") locomotives as common on the US and UK rail networks. Pollution produced from centralised generation of electricity is emitted at a distant power station, rather than "on site". Pollution can be reduced by using more railway electrification and [low carbon power](https://en.wikipedia.org/wiki/Low_carbon_power "Low carbon power") for electricity. Some railways, such as the French SNCF and Swiss federal railways derive most, if not 100% of their power, from hydroelectric or nuclear power stations, therefore atmospheric pollution from their rail networks is very low. This was reflected in a study by AEA Technology between a [Eurostar](https://en.wikipedia.org/wiki/Eurostar "Eurostar") train and airline journeys between London and Paris, which showed the trains on average emitting 10 times less CO2, per passenger, than planes, helped in part by French nuclear generation.[\[17\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-17) ### Hydrogen fuel cells \[[edit](https://en.wikipedia.org/w/index.php?title=Fuel_efficiency&action=edit&section=9 "Edit section: Hydrogen fuel cells")\] In the future, [hydrogen cars](https://en.wikipedia.org/wiki/Hydrogen_vehicle "Hydrogen vehicle") may be commercially available. Toyota is test-marketing vehicles powered by hydrogen fuel cells in southern California, where a series of hydrogen fueling stations has been established. Powered either through chemical reactions in a [fuel cell](https://en.wikipedia.org/wiki/Fuel_cell "Fuel cell") that create electricity to drive very efficient electrical motors or by directly burning hydrogen in a combustion engine (near identically to a [natural gas vehicle](https://en.wikipedia.org/wiki/Natural_gas_vehicle "Natural gas vehicle"), and similarly compatible with both natural gas and gasoline); these vehicles promise to have near-zero pollution from the tailpipe (exhaust pipe). Potentially the atmospheric pollution could be minimal, provided the hydrogen is made by [electrolysis](https://en.wikipedia.org/wiki/Electrolysis "Electrolysis") using electricity from non-polluting sources such as solar, wind or [hydroelectricity](https://en.wikipedia.org/wiki/Hydroelectricity "Hydroelectricity") or nuclear. Commercial [hydrogen production](https://en.wikipedia.org/wiki/Hydrogen_production "Hydrogen production") uses fossil fuels and produces more carbon dioxide than hydrogen. Because there are pollutants involved in the manufacture and destruction of a car and the production, transmission and storage of electricity and hydrogen, the label "zero pollution" applies only to the car's conversion of stored energy into movement. In 2004, a consortium of major auto-makers — [BMW](https://en.wikipedia.org/wiki/BMW "BMW"), [General Motors](https://en.wikipedia.org/wiki/General_Motors "General Motors"), [Honda](https://en.wikipedia.org/wiki/Honda "Honda"), [Toyota](https://en.wikipedia.org/wiki/Toyota "Toyota") and [Volkswagen](https://en.wikipedia.org/wiki/Volkswagen "Volkswagen")/[Audi](https://en.wikipedia.org/wiki/Audi "Audi") — came up with *"Top Tier Detergent Gasoline Standard"* to [gasoline](https://en.wikipedia.org/wiki/Gasoline "Gasoline") brands in the US and Canada that meet their minimum standards for [detergent](https://en.wikipedia.org/wiki/Detergent "Detergent") content[\[18\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-Top_Tier_Gasoline-18) and do not contain metallic additives. Top Tier gasoline contains higher levels of detergent additives in order to prevent the build-up of deposits (typically, on [fuel injector](https://en.wikipedia.org/wiki/Fuel_injector "Fuel injector") and [intake valve](https://en.wikipedia.org/wiki/Intake_valve "Intake valve")) known to reduce fuel economy and engine performance.[\[19\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-19) How fuel combusts affects how much energy is produced. The [National Aeronautics and Space Administration](https://en.wikipedia.org/wiki/National_Aeronautics_and_Space_Administration "National Aeronautics and Space Administration") (NASA) has investigated fuel consumption in [microgravity](https://en.wikipedia.org/wiki/Microgravity "Microgravity"). The common distribution of a flame under normal gravity conditions depends on [convection](https://en.wikipedia.org/wiki/Convection "Convection"), because soot tends to rise to the top of a flame, such as in a candle, making the flame yellow. In microgravity or [zero gravity](https://en.wikipedia.org/wiki/Zero_gravity "Zero gravity"), such as an environment in [outer space](https://en.wikipedia.org/wiki/Outer_space "Outer space"), convection no longer occurs, and the flame becomes [spherical](https://en.wikipedia.org/wiki/Sphere "Sphere"), with a tendency to become more blue and more efficient. There are several possible explanations for this difference, of which the most likely one given is the hypothesis that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs., National Aeronautics and Space Administration, April 2005. Experiments by NASA in microgravity reveal that [diffusion flames](https://en.wikipedia.org/wiki/Diffusion_flame "Diffusion flame") in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions.[LSP-1 experiment results](https://web.archive.org/web/20070312020123/http://microgravity.grc.nasa.gov/combustion/lsp/lsp1_results.htm), National Aeronautics and Space Administration, April 2005. [Premixed flames](https://en.wikipedia.org/wiki/Premixed_flame "Premixed flame") in microgravity burn at a much slower rate and more efficiently than even a candle on Earth, and last much longer.[\[20\]](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_note-20) - [Annual fuel utilization efficiency](https://en.wikipedia.org/wiki/Annual_fuel_utilization_efficiency "Annual fuel utilization efficiency") (AFUE) - [ACEA agreement](https://en.wikipedia.org/wiki/ACEA_agreement "ACEA agreement") - [Alternative propulsion](https://en.wikipedia.org/wiki/Alternative_propulsion "Alternative propulsion") - [Camless piston engine](https://en.wikipedia.org/wiki/Camless_piston_engine "Camless piston engine") - [Carbon dioxide equivalent](https://en.wikipedia.org/wiki/Carbon_dioxide_equivalent "Carbon dioxide equivalent") - [Corporate Average Fuel Economy](https://en.wikipedia.org/wiki/Corporate_Average_Fuel_Economy "Corporate Average Fuel Economy") (CAFE) - [EcoAuto](https://en.wikipedia.org/wiki/EcoAuto "EcoAuto") (in Canada) - [Efficient energy use](https://en.wikipedia.org/wiki/Efficient_energy_use "Efficient energy use") - [Emission standard](https://en.wikipedia.org/wiki/Emission_standard "Emission standard") - [Energy content of Biofuel](https://en.wikipedia.org/wiki/Energy_content_of_Biofuel "Energy content of Biofuel") - [Energy conservation](https://en.wikipedia.org/wiki/Energy_conservation "Energy conservation") - [Energy conversion efficiency](https://en.wikipedia.org/wiki/Energy_conversion_efficiency "Energy conversion efficiency") - [Energy density](https://en.wikipedia.org/wiki/Energy_density "Energy density") - [FF layout](https://en.wikipedia.org/wiki/FF_layout "FF layout") - [Front-wheel drive](https://en.wikipedia.org/wiki/Front-wheel_drive "Front-wheel drive") - [Fuel economy in aircraft](https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft "Fuel economy in aircraft") - [Fuel economy in automobiles](https://en.wikipedia.org/wiki/Fuel_economy_in_automobiles "Fuel economy in automobiles") - [Fuel economy maximising behaviors](https://en.wikipedia.org/wiki/Fuel_economy-maximizing_behaviors "Fuel economy-maximizing behaviors") - [Fuel efficiency in transportation](https://en.wikipedia.org/wiki/Fuel_efficiency_in_transportation "Fuel efficiency in transportation") - [Gas-guzzler](https://en.wikipedia.org/wiki/Gas-guzzler "Gas-guzzler") - [Heating value](https://en.wikipedia.org/wiki/Heating_value "Heating value") - [Jevons paradox](https://en.wikipedia.org/wiki/Jevons_paradox "Jevons paradox") - [Life cycle assessment](https://en.wikipedia.org/wiki/Life_cycle_assessment "Life cycle assessment") - [Low-rolling resistance tires](https://en.wikipedia.org/wiki/Low-rolling_resistance_tires "Low-rolling resistance tires") - [Miles per gallon gasoline equivalent](https://en.wikipedia.org/wiki/Miles_per_gallon_gasoline_equivalent "Miles per gallon gasoline equivalent") - [Marine fuel management](https://en.wikipedia.org/wiki/Marine_fuel_management "Marine fuel management") - [Twinjet](https://en.wikipedia.org/wiki/Twinjet "Twinjet") - [Variable valve timing](https://en.wikipedia.org/wiki/Variable_valve_timing "Variable valve timing") - [Unibody](https://en.wikipedia.org/wiki/Vehicle_frame#Unibody "Vehicle frame") - [Automobile costs](https://en.wikipedia.org/wiki/Automobile_costs "Automobile costs") - [Vehicle metrics](https://en.wikipedia.org/wiki/Vehicle_metrics "Vehicle metrics") 1. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-1)** ["Information on the fuel consumption of new cars"](https://web.archive.org/web/20190908124154/http://www.bilsweden.se/miljo-sakerhet/miljo/information-gallande-bransleforbrukning-for-nya-bilar). Archived from [the original](http://www.bilsweden.se/miljo-sakerhet/miljo/information-gallande-bransleforbrukning-for-nya-bilar) on 8 September 2019. Retrieved 7 November 2019. 2. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-2)** ["Learn More About the Fuel Economy Label for Gasoline Vehicles"](https://www.fueleconomy.gov/feg/label/learn-more-gasoline-label.shtml#fuel-consumption-rate). [Archived](https://web.archive.org/web/20130705143242/http://www.fueleconomy.gov/feg/label/learn-more-gasoline-label.shtml#fuel-consumption-rate) from the original on 2013-07-05. 3. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-3)** ["Simple tips and tricks to increase fuel efficiency of your car \| CarSangrah"](https://www.carsangrah.com/blog/simple-tips-tricks-enhance-fuel-efficiency-car). *CarSangrah*. 2018-06-07. Retrieved 2018-07-24. 4. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-4)** ["How Hybrids Work"](https://www.fueleconomy.gov/). [U.S. Department of Energy](https://en.wikipedia.org/wiki/U.S._Department_of_Energy "U.S. Department of Energy"). [Archived](https://web.archive.org/web/20150708093450/http://www.fueleconomy.gov/) from the original on 2015-07-08. Retrieved 2014-01-16. 5. ^ [***a***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-EPA_AutomotiveTrends_202212_5-0) [***b***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-EPA_AutomotiveTrends_202212_5-1) ["Highlights of the Automotive Trends Report"](https://www.epa.gov/automotive-trends/highlights-automotive-trends-report). *EPA.gov*. U.S. Environmental Protection Agency (EPA). 12 December 2022. [Archived](https://web.archive.org/web/20230902145941/https://www.epa.gov/automotive-trends/highlights-automotive-trends-report) from the original on 2 September 2023. 6. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-GlobalFuelEfficInit_202311_6-0)** Cazzola, Pierpaolo; Paoli, Leonardo; Teter, Jacob (November 2023). ["Trends in the Global Vehicle Fleet 2023 / Managing the SUV Shift and the EV Transition"](https://www.globalfueleconomy.org/media/792523/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf) (PDF). Global Fuel Economy Initiative (GFEI). p. 3. [doi](https://en.wikipedia.org/wiki/Doi_$identifier$ "Doi (identifier)"):[10\.7922/G2HM56SV](https://doi.org/10.7922%2FG2HM56SV). [Archived](https://web.archive.org/web/20231126092826/https://www.globalfueleconomy.org/media/792523/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf) (PDF) from the original on 26 November 2023. 7. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-7)** Calculated from heats of formation. Does not correspond exactly to the figure for MJ/L divided by density. 8. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-TEDB_8-0)** [Appendix B, Transportation Energy Data Book](http://www-cta.ornl.gov/data/Appendix_B.html) from the [Center for Transportation Analysis](https://en.wikipedia.org/wiki/Center_for_Transportation_Analysis "Center for Transportation Analysis") of the [Oak Ridge National Laboratory](https://en.wikipedia.org/wiki/Oak_Ridge_National_Laboratory "Oak Ridge National Laboratory") 9. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-9)** ["Efficiency"](http://www.merriam-webster.com/dictionary/efficiency). Retrieved 18 September 2016. 10. ^ [***a***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_fueleco_10-0) [***b***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_fueleco_10-1) [*Assessment of Fuel Economy Technologies for Light-duty Vehicles*](http://www.nap.edu/read/12924/chapter/4). The National Academies Press. 2011. [doi](https://en.wikipedia.org/wiki/Doi_$identifier$ "Doi (identifier)"):[10\.17226/12924](https://doi.org/10.17226%2F12924). [ISBN](https://en.wikipedia.org/wiki/ISBN_$identifier$ "ISBN (identifier)") [978-0-309-15607-3](https://en.wikipedia.org/wiki/Special:BookSources/978-0-309-15607-3 "Special:BookSources/978-0-309-15607-3") . Retrieved 18 September 2016. 11. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy_efficiency_in_transport_DOEgloss_11-0)** ["Glossary of energy-related terms"](http://energy.gov/eere/energybasics/articles/glossary-energy-related-terms#E). [U.S. Department of Energy](https://en.wikipedia.org/wiki/U.S._Department_of_Energy "U.S. Department of Energy"). Retrieved 20 September 2016. 12. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-12)** Page, Walter Hines; Page, Arthur Wilson (1916). ["Man and His Machines"](https://books.google.com/books?id=lPAMVa7esS4C). *The World's Work*. Vol. XXXIII. Garden City, New York: Doubleday, Page & Co. 13. ^ [***a***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy-efficient_driving_Beusen_13-0) [***b***](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy-efficient_driving_Beusen_13-1) Beusen; et al. (2009). ["Using on-board logging devices to study the long-term impact of an eco-driving course"](https://www.researchgate.net/publication/231614817). *Transportation Research D*. **14** (7): 514–520\. [Bibcode](https://en.wikipedia.org/wiki/Bibcode_$identifier$ "Bibcode (identifier)"):[2009TRPD...14..514B](https://ui.adsabs.harvard.edu/abs/2009TRPD...14..514B). [doi](https://en.wikipedia.org/wiki/Doi_$identifier$ "Doi (identifier)"):[10\.1016/j.trd.2009.05.009](https://doi.org/10.1016%2Fj.trd.2009.05.009). [Archived](https://web.archive.org/web/20131019115218/http://www.researchgate.net/publication/231614817_Using_on-board_logging_devices_to_study_the_long-term_impact_of_an_eco-driving_course?ev=prf_pub) from the original on 2013-10-19. 14. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-14)** ["20 Ways to Improve Your Fuel Efficiency and Save Money at the Pump"](http://car1.ca/blog/2016/08/02/20-ways-to-improve-your-fuel-efficiency-and-save-money-at-the-pump/). [Archived](https://web.archive.org/web/20160816132350/http://car1.ca/blog/2016/08/02/20-ways-to-improve-your-fuel-efficiency-and-save-money-at-the-pump/) from the original on 2016-08-16. 15. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Energy-efficient_driving_merriam-webster.com_15-0)** <http://www.merriam-webster.com/dictionary/hypermiling> Merriam Webster dictionary 16. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-16)** ["Staying Ahead Of The Curve: 3 Key Fleet Management Trends For 2023"](https://www.forbes.com/councils/forbestechcouncil/2023/04/18/staying-ahead-of-the-curve-3-key-fleet-management-trends-for-2023/). *Forbes*. April 18, 2023. Retrieved October 7, 2025. 17. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-17)** ["Rail 10 times better than air in London-Paris CO2 comparison - Transport & Environment"](http://www.transportenvironment.org/Article267.html). [Archived](https://web.archive.org/web/20070928024427/http://www.transportenvironment.org/Article267.html) from the original on 2007-09-28. 18. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-Top_Tier_Gasoline_18-0)** [Top Tier Gasoline](http://www.toptiergas.com/retailers.html) [Archived](https://web.archive.org/web/20130815031514/http://www.toptiergas.com/retailers.html) 2013-08-15 at the [Wayback Machine](https://en.wikipedia.org/wiki/Wayback_Machine "Wayback Machine") 19. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-19)** ["Deposit Control Standards"](https://web.archive.org/web/20040806012056/http://www.toptiergas.com/deposit_control.html). Archived from [the original](http://www.toptiergas.com/deposit_control.html) on 2004-08-06. Retrieved 2012-10-19. 20. **[^](https://en.wikipedia.org/wiki/Fuel_efficiency#cite_ref-20)** [SOFBAL-2 experiment results](https://microgravity.grc.nasa.gov/combustion/lsp/lsp1_results.htm) [Archived](https://web.archive.org/web/20070312020123/http://microgravity.grc.nasa.gov/combustion/lsp/lsp1_results.htm) 2007-03-12 at the [Wayback Machine](https://en.wikipedia.org/wiki/Wayback_Machine "Wayback Machine"), National Aeronautics and Space Administration, April 2005. - [US Government website on fuel economy](https://www.fueleconomy.gov/) - [UK DfT comparisons on road and rail](http://www.dft.gov.uk/stellent/groups/dft_railways/documents/page/dft_railways_611287.pdf) - [NASA Offers a \$1.5 Million Prize for a Fast and Fuel-Efficient Aircraft](http://apps1.eere.energy.gov/news/news_detail.cfm/news_id=12694) [Archived](https://web.archive.org/web/20160303200449/http://apps1.eere.energy.gov/news/news_detail.cfm/news_id=12694) 2016-03-03 at the [Wayback Machine](https://en.wikipedia.org/wiki/Wayback_Machine "Wayback Machine") - [Car Fuel Consumption Official Figures](http://www.carfuelconsumption.com/) - [Spritmonitor.de "the most fuel efficient cars" - Database of thousands of (mostly German) car owners' actual fuel consumption figures](https://www.spritmonitor.de/de/die_sparsamsten_autos.html) (cf. [Spritmonitor](https://en.wikipedia.org/wiki/Spritmonitor "Spritmonitor")) - [Searchable fuel economy data from the EPA - United States Environmental Protection Agency](https://web.archive.org/web/20131029195658/http://fueleconomy.carconsumption.com/) - [penghemat bbm - Alat penghemat bbm](http://www.xpower-ionizer.com/) - [Ny Times: A Road Test of Alternative Fuel Visions](https://www.nytimes.com/2014/11/18/science/earth/hydrogen-cars-join-electric-models-in-showrooms.html)

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