View source for Fuel economy in automobiles

{{Short description|Distance traveled by a vehicle compared to volume of fuel consumed}}
{{Use American English|date=January 2023}}
{{Use dmy dates|date=January 2023}}
[[File:2006 Honda Airwave fuel efficiency meter.jpg|thumb|right|Fuel consumption monitor from a 2006 [[Honda Airwave]]. The displayed fuel economy is {{convert|18.1|km/L|L/100km mpgus|abbr=on}}.]]
[[File:Fuel Economy, 1916.jpg|right|thumb|A [[Briggs and Stratton Flyer]] from 1916. Originally an experiment in creating a fuel-saving automobile in the United States, the vehicle weighed only {{convert|135|lb|kg|1|abbr=on}} and was an adaptation of a small gasoline engine originally designed to power a bicycle.<ref>{{cite magazine |title=Man and His Machines |magazine=The World's Work |publisher=Doubleday, Page & Co. |location=Garden City, New York |volume=XXXIII |year=1916 |url=https://books.google.com/books?id=lPAMVa7esS4C |last1=Page |first1=Walter Hines |last2=Page |first2=Arthur Wilson}}</ref>]]

The '''fuel economy''' of an [[Car|automobile]] relates to the distance traveled by a vehicle and the amount of [[fuel consumption|fuel consumed]]. Consumption can be expressed in terms of the volume of fuel to travel a distance, or the distance traveled per unit volume of fuel consumed. Since fuel consumption of vehicles is a significant factor in air pollution, and since the importation of [[motor fuel]] can be a large part of a nation's [[foreign trade]], 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 car]]s do not directly burn fuel, and so do not have fuel economy per se, but equivalence measures, such as [[miles per gallon gasoline equivalent]] have been created to attempt to compare them.

==Quantities and units of measure==
[[File:Chart MPG to L-100km v2009-10-08.svg|thumb|right|400px|Conversion from mpg to L/100 km: blue, U.S. [[gallon]]; red, imperial gallon]]

The fuel efficiency of motor vehicles can be expressed in more ways:
* '''Fuel consumption''' is the amount of fuel used per unit distance; for example, '''[[litre]]s per 100 [[kilometre]]s (L/100&nbsp;km)'''. The '''lower''' the value, the more economic a vehicle is (the less fuel it needs to travel a certain distance); this is the measure generally used across Europe (except the UK, Denmark and The Netherlands - see below), New Zealand, Australia and Canada. Also in Uruguay, Paraguay, Guatemala, Colombia, China, and Madagascar.{{Citation needed|date=November 2010}}, as also in post-Soviet space.
* '''Fuel economy''' is the distance travelled per unit volume of fuel used; for example, '''kilometres per litre (km/L)''' or '''[[mile]]s per [[gallon]] (MPG)''', where 1 MPG (imperial) ≈ 0.354006&nbsp;km/L.  The '''higher''' the value, the more economic a vehicle is (the more distance it can travel with a certain volume of fuel). This measure is popular in the US and the UK (mpg), but in Europe, India, Japan, South Korea and Latin America the metric unit ''km/L'' is used instead.

The formula for converting to miles per US gallon (3.7854 L) from L/100&nbsp;km is <math>\textstyle \frac{235.215}{x}</math>, where <math>x</math> is value of L/100&nbsp;km. For miles per Imperial gallon (4.5461 L) the formula is <math>\textstyle \frac{282.481}{x}</math>.

In parts of Europe, the two standard measuring cycles for "litre/100 km" value are "urban" traffic with speeds up to 50&nbsp;km/h from a cold start, and then "extra urban" travel at various speeds up to 120&nbsp;km/h which follows the urban test. A combined figure is also quoted showing the total fuel consumed in divided by the total distance traveled in both tests.

Fuel economy can be expressed in two ways:

;Units of fuel per fixed distance:Generally expressed in liters per 100 kilometers (L/100&nbsp;km), used in most European countries, China, South Africa, Australia and New Zealand. Irish law allows for the use of miles per imperial [[gallon]], alongside liters per 100 kilometers.<ref>{{cite web | url=http://www.thejournal.ie/dear-driver-what-is-good-mpg-3150884-Dec2016/ |title = What counts as 'good' MPG nowadays?| date=21 December 2016 }}</ref> Canadian law requires fuel economy to be measured in both liters per 100 kilometers and miles per imperial [[gallon]].<ref>{{cite web |url=http://www.oee.nrcan.gc.ca/transportation/tools/fuelratings/ratings-search.cfm?attr=8 |title=Fuel Consumption Ratings |access-date=8 June 2011 |date=January 2011 |publisher=Government of Canada}}</ref><ref>{{cite web |url=http://www.tc.gc.ca/eng/programs/environment-fcp-faq-139.htm |title=FAQs – Transport Canada |access-date=6 November 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120903133543/http://www.tc.gc.ca/eng/programs/environment-fcp-faq-139.htm |archive-date=3 September 2012 }}</ref><ref>{{cite web |url=http://www.legislation.gov.uk/uksi/2001/3523/schedule/1/made |title=The Passenger Car (Fuel Consumption and CO2 Emissions Information) Regulations 2001 |year=2001 |access-date=11 November 2014}}</ref> Liters per 100 kilometers may be used alongside miles per imperial [[gallon]] in the UK. The [[Monroney sticker|window sticker]] on new US cars displays the vehicle's fuel consumption in US gallons per 100 miles, in addition to the traditional mpg number.<ref>[http://www.fueleconomy.gov/feg/label/learn-more-gasoline-label.shtml The New Fuel Economy Label] at FuelEconomy.gov</ref> A lower number means more efficient, while a higher number means less efficient.

;Units of distance per fixed fuel unit: Miles per [[gallon]] (mpg) are commonly used in the United States, the United Kingdom, and Canada (alongside L/100&nbsp;km). Kilometers per liter (km/L) are more commonly used elsewhere in the Americas, Asia, parts of Africa and Oceania. In the [[Greater Syria|Levant]] km/20&nbsp;L is used, known as kilometers per ''[[wikt:تنكة|tanaka]]'', a [[Jerrycan|metal container]] which has a volume of twenty liters.  When mpg is used, it is necessary to identify the type of gallon: the imperial gallon is 4.54609 liters, and the U.S. gallon is 3.785 liters.  When using a measure expressed as distance per fuel unit, a higher number means more efficient, while a lower number means less efficient.

'''Conversions of units:'''
{| border=0
|-
| style="background:azure;"| Miles per '''US''' gallon → L/100&nbsp;km:
| style="background:#FFE0E0;"| <math>\frac {235}{\rm mpg_{US}} = \rm 1\; L/100\; km</math>
| style="background:#fff;"| &nbsp;&nbsp;&nbsp;
| style="background:azure;"| L/100&nbsp;km → Miles per '''US''' gallon:
| style="background:#FFE0E0;"| <math>\frac {235}{\rm L/100\; km} = \rm 1\; mpg_{US}</math>
|-
| style="background:#E0FFFF;"| Miles per '''Imperial''' gallon → L/100&nbsp;km:
| style="background:#FFD0D0;"| <math>\frac {282}{\rm mpg_{Imp}} = \rm 1\; L/100\; km</math>
| style="background:#fff;"| &nbsp;&nbsp;&nbsp;
| style="background:#E0FFFF;"| L/100&nbsp;km → Miles per '''Imperial''' gallon:
| style="background:#FFD0D0;"| <math>\frac {282}{\rm L/100\; km} = \rm 1\; mpg_{Imp}</math>
|- style="background:#fff;" 
|| &nbsp;
|| &nbsp;
|| &nbsp;
|| &nbsp;
|| &nbsp;
|-
| style="background:azure;"| Miles per '''US''' gallon → km/20&nbsp;L:
| style="background:#FFE0E0;"| <math>\rm 8.5\; mpg_{US} = 1\; km/20\;L</math>
|-
| style="background:#E0FFFF;"| L/100&nbsp;km → km/20&nbsp;L:
| style="background:#FFD0D0;"| <math>\frac {2000}{\rm L/100\; km} = \rm 1\; km/20\;L</math>
|- style="background:#fff;" 
|| &nbsp;
|| &nbsp;
|| &nbsp;
|| &nbsp;
|| &nbsp;
|-
| style="background:azure;"| Miles per '''US''' gallon → Miles per '''Imperial''' gallon:
| style="background:#FFE0E0;"| <math>1\; \rm mpg_{US} = \rm 0.8327\; \rm mpg_{Imp}</math>
|-
| style="background:azure;"| Miles per '''Imperial''' gallon → Miles per '''US''' gallon:
| style="background:#FFE0E0;"| <math>1\; \rm mpg_{Imp} = 1.2001\; \rm mpg_{US}</math>
|}

==Statistics==
[[File:1975- US vehicle production share, by vehicle type.svg |thumb|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 of carbon dioxide emissions.<ref name=EPA_AutomotiveTrends_202212>{{cite web |title=Highlights of the Automotive Trends Report |url=https://www.epa.gov/automotive-trends/highlights-automotive-trends-report |website=EPA.gov |publisher=U.S. Environmental Protection Agency (EPA) |archive-url=https://web.archive.org/web/20230902145941/https://www.epa.gov/automotive-trends/highlights-automotive-trends-report |archive-date=2 September 2023 |date=12 December 2022 |url-status=live}}</ref> Without the shift towards SUVs, energy use per unit distance could have fallen 30% more than it did from 2010 to 2022.<ref name=GlobalFuelEfficInit_202311>{{cite web |last1=Cazzola |first1=Pierpaolo |last2=Paoli |first2=Leonardo |last3=Teter |first3=Jacob |title=Trends in the Global Vehicle Fleet 2023 / Managing the SUV Shift and the EV Transition |url=https://www.globalfueleconomy.org/media/792523/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf |publisher=Global Fuel Economy Initiative (GFEI) |archive-url=https://web.archive.org/web/20231126092826/https://www.globalfueleconomy.org/media/792523/gfei-trends-in-the-global-vehicle-fleet-2023-spreads.pdf |archive-date=26 November 2023 |page=3 |doi=10.7922/G2HM56SV |date=November 2023 |url-status=live }}</ref>]]
While the [[thermal efficiency]] (mechanical output to chemical energy in fuel) of petroleum [[internal combustion engine|engines]] has increased since the beginning of the [[History of the automobile|automotive era]], this is not the only factor in fuel economy. The design of automobile as a whole and usage pattern affects the fuel economy. Published fuel economy is subject to variation between jurisdiction due to variations in testing protocols.

One of the first studies to determine fuel economy in the United States was the [[Mobil Economy Run]], which was an event that took place every year from 1936 (except during [[World War II]]) to 1968. It was designed to provide real, efficient [[fuel efficiency]] numbers during a coast-to-coast test on real roads and with regular traffic and weather conditions. The [[Mobil]] Oil Corporation sponsored it and the [[United States Auto Club]] (USAC) sanctioned and operated the run. In more recent studies, the average fuel economy for new passenger car in the United States improved from 17 mpg (13.8 L/100&nbsp;km) in 1978 to more than 22 mpg (10.7 L/100&nbsp;km) in 1982.<ref>{{cite journal |author1=Paul R. Portney |author2=Ian W.H. Parry |author3=Howard K. Gruenspecht |author4=Winston Harrington |title=The Economics of Fuel Economy Standards |publisher=Resources for the Future |date=November 2003 |url=http://www.rff.org/documents/RFF-DP-03-44.pdf |access-date=4 January 2008 |archive-url=https://web.archive.org/web/20071201031917/http://www.rff.org/documents/RFF-DP-03-44.pdf |archive-date=1 December 2007 |url-status=dead }}</ref>
The average{{efn|Specifically, the production-weighted [[harmonic mean]]}} fuel economy for new 2020 model year cars, light trucks and SUVs in the United States was {{convert|25.4|mpgus|L/100 km}}.<ref>{{cite web |title=Highlights of the Automotive Trends Report |url=https://www.epa.gov/automotive-trends/highlights-automotive-trends-report |website=US EPA |access-date=30 November 2021 |language=en |date=November 2021}}</ref> 2019 model year cars (ex. EVs) classified as "midsize" by the US EPA ranged from 12 to 56 mpg<sub>US</sub> (20 to 4.2 L/100&nbsp;km)<ref name=2019_epa_BestandWorst>{{cite web|title=2019 Best and Worst Fuel Economy Vehicles|url=https://www.fueleconomy.gov/feg/best-worst.shtml|publisher=US EPA|access-date=23 June 2019}}</ref> However, due to environmental concerns caused by CO<sub>2</sub> emissions, new EU regulations are being introduced to reduce the average emissions of cars sold beginning in 2012, to 130 g/km of CO<sub>2</sub>, equivalent to 4.5 L/100&nbsp;km (52 mpg<sub>US</sub>, 63 mpg<sub>imp</sub>) for a diesel-fueled car, and 5.0 L/100&nbsp;km (47 mpg<sub>US</sub>, 56 mpg<sub>imp</sub>) for a gasoline (petrol)-fueled car.<ref>[http://ec.europa.eu/clima/policies/transport/vehicles/cars_en.htm Reducing CO2 emissions from passenger cars – Policies – Climate Action – European Commission]. Ec.europa.eu (9 December 2010). Retrieved 21 September 2011.</ref>

The average consumption across the fleet is not immediately affected by the ''new vehicle'' fuel economy: for example, Australia's car fleet average in 2004 was 11.5 L/100&nbsp;km (20.5 mpg<sub>US</sub>),<ref>[http://www.ptua.org.au/myths/efficient.shtml Myth: Cars are becoming more fuel efficient]. Ptua.org.au. Retrieved 21 September 2011.</ref> compared with the average new car consumption in the same year of 9.3 L/100&nbsp;km (25.3 mpg<sub>US</sub>)<ref name="pew"/>

===Speed and fuel economy studies===
[[File:Fuel economy vs speed 1997.png|thumb|1997 fuel economy statistics for various US models]]
Fuel economy at steady speeds with selected vehicles was studied in 2010. The most recent study<ref name=ornl>[http://cta.ornl.gov/data/tedb31/Edition31_Full_Doc.pdf Steady Speed Fuel Economy] {{webarchive|url=https://web.archive.org/web/20120924201205/http://cta.ornl.gov/data/tedb31/Edition31_Full_Doc.pdf |date=24 September 2012 }} "The two earlier studies by the Federal Highway Administration (FHWA) indicate maximum fuel efficiency was achieved at speeds of 35 to 40 mph (55 to 65 km/h). The recent FHWA study indicates greater fuel efficiency at higher speeds."</ref> indicates greater fuel efficiency at higher speeds than earlier studies; for example, some vehicles achieve better fuel economy at {{convert|100|km/h|mi/h|abbr=on}} rather than at {{convert|70|km/h|mi/h|abbr=on}},<ref name=ornl/> although not their best economy, such as the 1994 [[Oldsmobile Cutlass Ciera]] with the [[General Motors 122 engine#LN2|LN2]] 2.2L engine, which has its best economy at {{convert|90|km/h|mph|abbr=on}} ({{convert|8.1|L/100 km|mpgus|abbr=on}}), and gets better economy at {{convert|105|km/h|mph|abbr=on}} than at {{convert|72|km/h|mi/h|abbr=on}} ({{convert|9.4|L/100 km|mpgus|abbr=on}} vs {{convert|22|mpgus|L/100 km|abbr=on}}). The proportion of driving on [[Highway safety#Motorway|high speed roadways]] varies from 4% in Ireland to 41% in the Netherlands.

When the US [[National Maximum Speed Law]]'s {{convert|55|mi/h|km/h|abbr=on}} speed limit was mandated from 1974 to 1995, there were complaints that fuel economy could decrease instead of increase. The 1997 Toyota Celica got better fuel-efficiency at {{convert|105|km/h|mi/h|abbr=on}} than it did at {{convert|65|km/h|mi/h|abbr=on}} ({{convert|5.41|L/100 km|mpgus|abbr=on}} vs {{convert|5.53|L/100 km|mpgus|abbr=on}}), although even better at {{convert|60|mi/h|km/h|abbr=on}} than at {{convert|65|mi/h|km/h|abbr=on}} ({{convert|48.4|mpgus|L/100 km|abbr=on}} vs {{convert|43.5|mpgus|L/100 km|abbr=on}}), and its best economy ({{convert|52.6|mpgus|L/100 km|abbr=on}}) at only {{convert|25|mi/h|km/h|abbr=on}}. Other vehicles tested had from 1.4 to 20.2% better fuel-efficiency at {{convert|90|km/h|mi/h|abbr=on}} vs. {{convert|105|km/h|mi/h|abbr=on}}. Their best economy was reached at speeds of {{convert|40|to|90|km/h|mi/h|abbr=on}} (see graph).<ref name=ornl/>

Officials hoped that the {{convert|55|mph|abbr=on}} limit, combined with a ban on ornamental lighting, no gasoline sales on Sunday, and a 15% cut in gasoline production, would reduce total gasoline consumption by 200,000 [[oil barrel|barrels]] a day, representing a 2.2% drop from annualized 1973 gasoline consumption levels.<ref>{{cite news |title= Politics and Energy: Nixon's Silence on Rationing Reflects Hope That Austerity Can Be Avoided  |last= Cowan |first= Edward |work= The New York Times |page= 30 |date= 27 November 1973}}</ref>{{refn|The 2.2% drop figure was calculated by finding daily consumption to be 9,299,684 barrels of petroleum. Obtain 1973's petroleum consumption from transportation sector at 2.1e from the Energy Consumption by Sector section, then convert to barrels using A1 in the Thermal Conversion Factors section (assume "conventional motor gasoline" since ethanol-based or purportedly smog-reducing gas was not common in 1973).<ref>{{cite book |author= Staff |url= http://www.eia.gov/FTPROOT/multifuel/038407.pdf |archive-url= https://web.archive.org/web/20180926014110/https://www.eia.gov/FTPROOT/multifuel/038407.pdf |url-status= dead |archive-date= 26 September 2018 |title= Annual Energy Review |edition= 2007 |location= Washington, DC |publisher= Energy Information Administration |date= 28 June 2008 }}</ref>
 |name= |group=lower-alpha}} This was partly based on a belief that cars achieve maximum efficiency between 40 and 50&nbsp;mph (65 and 80&nbsp;km/h) and that trucks and buses were most efficient at {{convert|55|mph|abbr=on}}.<ref>{{cite news |title= 55 Mile-per-hour Speed Limit Approved by House |access-date=22 July 2008 |url= http://infoweb.newsbank.com/iw-search/we/HistArchive/?p_action=doc&p_queryname=3&p_docid=0FCAA40565438742&p_docnum=20&s_pagesearch=no&s_ARTICLE_ID=0FCAA40565438742&s_RELEASE=release_0005&s_ISSUE_ID=0FCAA4036C446D57&s_FORMAT=gif&s_SIZE=display&s_SEARCHED=%28+%28%28pty%253A10+%29+OR+%28pty%253A40+%29+OR+%28pty%253A50+%29+OR+%28pty%253A60+%29%29+%29+and+%28+ibd%253A%255B2441684%253B2442414%255D+%29+and+%28+%2855%29+AND+%28speed++AND+limit%29+%29+&p_product=DMHA&p_theme=dmn&p_nbid=R5FY50FIMTIxNjc0NDY1Mi4yNjE1OjE6MTU6MTI5LjExOS4yNDguMjUx |agency= [[United Press International]] |page= 30 |date= 4 December 1973}} {{subscription required}}</ref>

In 1998, the U.S. [[Transportation Research Board]] footnoted an estimate that the 1974 National Maximum Speed Limit (NMSL) reduced fuel consumption by 0.2 to 1.0 percent.<ref>{{cite journal |title= Special Report 254: Managing Speed |access-date=17 September 2014 |url= http://onlinepubs.trb.org/onlinepubs/sr/sr254.pdf |quote=Bloomquist (1984) estimated that the 1974 National Maximum Speed Limit (NMSL) reduced fuel consumption by 0.2 to 1.0 percent. |publisher= [[Transportation Research Board]] |page= 189 }}</ref> Rural interstates, the roads most visibly affected by the NMSL, accounted for 9.5% of the U.S' vehicle-miles-traveled in 1973,<ref>{{cite journal |title= Highway Statistics 1973 (Table VM-2: VEHICLE MILES, BY STATE AND HIGHWAY SYSTEM-1973) |access-date= 17 September 2014 |url= http://isddc.dot.gov/OLPFiles/FHWA/012894.pdf |publisher= [[Federal Highway Administration]] |page= 76 |url-status= dead |archive-url= https://web.archive.org/web/20130304135803/http://isddc.dot.gov/OLPFiles/FHWA/012894.pdf |archive-date= 4 March 2013 |df= dmy-all }}</ref> but such free-flowing roads typically provide more fuel-efficient travel than conventional roads.<ref name="greenvehicleguide.gov.au">{{cite web|url=http://www.greenvehicleguide.gov.au/GVGPublicUI/CompareVehicles.aspx|title=Lexus IS250 2.5L 6cyl, Auto 6 speed Sedan, 5 seats, 2WD|url-status=dead|archive-url=https://archive.today/20120804211351/http://www.greenvehicleguide.gov.au/GVGPublicUI/CompareVehicles.aspx|archive-date=4 August 2012}}</ref>
<ref name="lexus.de">''IS 250 Kraftstoffverbrauch kombiniert 8,9 L/100 km (innerorts 12,5 L/ außerorts 6,9 L) bei CO2-Emissionen von 209 g/km nach dem vorgeschriebenen EU-Messverfahren'' {{cite web |url=http://www.lexus.de/range/is/index.aspx |title=LEXUS – Lexus – IS – Sportlimousine – Cabriolet – Cabrio – Kabrio – Coupé – Coupe – Hochleistung IS F – High-Performance-Fahrzeug IS F |access-date=22 April 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100402102635/http://www.lexus.de/range/IS/Index.aspx |archive-date=2 April 2010 }}</ref>
<ref name="fueleconomy.gov">''2009 Lexus IS 250 6 cyl, 2.5 L, Automatic (S6), Premium'' http://www.fueleconomy.gov/feg/findacar.htm</ref>

===Discussion of statistics===
A reasonably modern European [[supermini car|supermini]] and many mid-size cars, including station wagons, may manage [[motorway]] travel at 5 L/100&nbsp;km (47 mpg US/56 mpg imp) or 6.5 L/100&nbsp;km in city traffic (36 mpg US/43 mpg imp), with [[carbon dioxide]] emissions of around 140 g/km.

An average [[North America]]n [[mid-size car]] travels 21 mpg (US) (11 L/100&nbsp;km) city, 27 mpg (US) (9 L/100&nbsp;km) highway; a [[full-size car|full-size]] [[SUV]] usually travels 13 mpg (US) (18 L/100&nbsp;km) city and 16 mpg (US) (15 L/100&nbsp;km) highway.  [[Pickup truck]]s vary considerably; whereas a 4 cylinder-engined light pickup can achieve 28 mpg (8 L/100&nbsp;km), a [[V8 engine|V8]] full-size pickup with extended cabin only travels 13 mpg (US) (18 L/100&nbsp;km) city and 15 mpg (US) (15 L/100&nbsp;km) highway.

The average fuel economy for all vehicles on the road is higher in Europe than the United States because the higher cost of fuel changes [[consumer behaviour]]. In the UK, a gallon of gas without tax would cost US$1.97, but with taxes cost US$6.06 in 2005. The average cost in the United States was US$2.61.<ref>{{cite journal|url=http://www.csmonitor.com/2005/0826/p01s03-woeu.html|title=Gas prices too high? Try Europe.|date=26 August 2005|journal=Christian Science Monitor|url-status=live|archive-url=https://web.archive.org/web/20120918025725/http://www.csmonitor.com/2005/0826/p01s03-woeu.html|archive-date=18 September 2012}}</ref>

European-built cars are generally more fuel-efficient than US vehicles. While Europe has many higher efficiency diesel cars, European gasoline vehicles are on average also more efficient than gasoline-powered vehicles in the USA. Most European vehicles cited in the CSI study run on diesel engines, which tend to achieve greater fuel efficiency than gas engines. Selling those cars in the United States is difficult because of emission standards, notes Walter McManus, a fuel economy expert at the University of Michigan Transportation Research Institute. "For the most part, European diesels don’t meet U.S. emission standards", McManus said in 2007. Another reason why many European models are not marketed in the United States is that labor unions object to having the big 3 import any new foreign built models regardless of fuel economy while laying off workers at home.<ref>{{cite web|url=http://www.nbcnews.com/id/17344368|title=U.S. 'stuck in reverse' on fuel economy|website=[[NBC News]] |date=28 February 2007}}</ref>

An example of European cars' capabilities of fuel economy is the [[microcar]] ''[[Smart Fortwo]]'' cdi, which can achieve up to 3.4 L/100&nbsp;km (69.2 mpg US) using a [[turbocharger|turbocharged]] three-cylinder 41&nbsp;bhp (30&nbsp;kW) Diesel engine. The Fortwo is produced by [[Daimler AG]] and is only sold by one company in the United States. Furthermore, the world record in fuel economy of production cars is held by the [[Volkswagen Group]], with special production models (labeled "3L") of the [[Volkswagen Lupo#Lupo 3L|Volkswagen Lupo]] and the [[Audi A2#1.2 TDI "3L"|Audi A2]], consuming as little as {{convert|3|L/100 km|abbr=on}}.<ref>{{cite web|url=http://usatoday30.usatoday.com/money/consumer/autos/mareview/mauto497.htm|title=VW Lupo: Rough road to fuel economy}}</ref>{{clarify|Is this still true after Dieselgate?|date=July 2019}}

[[Diesel engine]]s generally achieve greater fuel efficiency than petrol (gasoline) engines. Passenger car diesel engines have [[Energy conversion efficiency|energy efficiency]] of up to 41% but more typically 30%, and petrol engines of up to 37.3%, but more typically 20%. A common margin is 25% more miles per gallon for an efficient turbodiesel.

For example, the current model Skoda Octavia, using Volkswagen engines, has a combined European fuel efficiency of {{convert|41.3|mpgUS|L/100km|abbr=on}} for the {{convert|105|bhp|abbr=on}} petrol engine and {{convert|52.3|mpgUS|L/100km|abbr=on}} for the {{convert|105|bhp|abbr=on}} — and heavier — diesel engine. The higher compression ratio is helpful in raising the energy efficiency, but diesel fuel also contains approximately 10% more energy per unit volume than gasoline which contributes to the reduced fuel consumption for a given power output.

In 2002, the United States had 85,174,776 trucks, and averaged {{convert|13.5|mpgus}}. Large trucks, over {{convert|33,000|lb}}, averaged {{convert|5.7|mpgus}}.<ref>[http://cta.ornl.gov/data/chapter5.shtml Heavy Vehicles and Characteristics] {{webarchive|url=https://web.archive.org/web/20120723162849/http://cta.ornl.gov/data/chapter5.shtml |date=2012-07-23 }} Table 5.4</ref>

{| class=wikitable
|+Truck fuel economy
|-
![[Gross vehicle weight rating|GVWR]] lbs!!Number!!Percentage!!Average miles per truck!!fuel economy!!Percentage of fuel use
|-
|6,000&nbsp;lbs and less||51,941,389||61.00%||11,882||17.6||42.70%
|-
|6,001 – 10,000&nbsp;lbs||28,041,234||32.90%||12,684||14.3||30.50%
|-
!Light truck subtotal!!79,982,623!!93.90%!!12,163!!16.2!!73.20%
|-
|10,001 – 14,000&nbsp;lbs||691,342||0.80%||14,094||10.5||1.10%
|-
|14,001 – 16,000&nbsp;lbs||290,980||0.30%||15,441||8.5||0.50%
|-
|16,001 – 19,500&nbsp;lbs||166,472||0.20%||11,645||7.9||0.30%
|-
|19,501 – 26,000&nbsp;lbs||1,709,574||2.00%||12,671||7||3.20%
|-
!Medium truck subtotal!!2,858,368!!3.40%!!13,237!!8!!5.20%
|-
|26,001 – 33,000&nbsp;lbs||179,790||0.20%||30,708||6.4||0.90%
|-
|33,001&nbsp;lbs and up||2,153,996||2.50%||45,739||5.7||20.70%
|-
!Heavy truck subtotal!!2,333,786!!2.70%!!44,581!!5.8!!21.60%
|-
!Total!!85,174,776!!100.00%!!13,088!!13.5!!100.00%
|}

The average economy of automobiles in the United States in 2002 was {{convert|22.0|mpgus}}. By 2010 this had increased to {{convert|23.0|mpgus}}. Average fuel economy in the United States gradually declined until 1973, when it reached a low of {{convert|13.4|mpgus}} and gradually has increased since, as a result of higher fuel cost.<ref>[http://cta.ornl.gov/data/chapter4.shtml Light Vehicles and Characteristics] {{webarchive|url=https://web.archive.org/web/20120915163525/http://cta.ornl.gov/data/chapter4.shtml |date=2012-09-15 }} Table 4.1</ref> A study indicates that a 10% increase in gas prices will eventually produce a 2.04% increase in fuel economy.<ref>[http://www.aeaweb.org/articles.php?doi=10.1257/pol.1.2.113  How Do Gasoline Prices Affect Fleet Fuel Economy?] {{webarchive|url=https://web.archive.org/web/20121021131856/http://www.aeaweb.org/articles.php?doi=10.1257%2Fpol.1.2.113 |date=2012-10-21 }}</ref> One method by car makers to increase fuel efficiency is [[lightweighting]] in which lighter-weight materials are substituted in for improved engine performance and handling.<ref name=twsMercuryNews>Dee-Ann Durbin of the Associated Press, June 17, 2014, Mercury News, [http://www.mercurynews.com/business/ci_25981045/auto-industry-gets-serious-about-lighter-materials Auto industry gets serious about lighter materials] {{webarchive|url=https://web.archive.org/web/20150415082011/http://www.mercurynews.com/business/ci_25981045/auto-industry-gets-serious-about-lighter-materials |date=2015-04-15 }}, Retrieved April 11, 2015, "...Automakers have been experimenting for decades with lightweighting...  the effort is gaining urgency with the adoption of tougher gas mileage standards. ..."</ref>

===Differences in testing standards===
Identical vehicles can have varying fuel consumption figures listed depending upon the testing methods of the jurisdiction.<ref>{{cite web|last1=Yang|first1=Zifei|last2=Bandivadekar|first2=Anup|title=Light-duty vehicle greenhouse gas and fuel economy standards|url=http://www.theicct.org/sites/default/files/publications/2017-Global-LDV-Standards-Update_ICCT-Report_23062017_vF.pdf|publisher=International Council on Clean Transportation|access-date=1 December 2017}}</ref>

Lexus [[Lexus IS#Second generation (2006–present)|IS 250]] – petrol 2.5 L ''[[Toyota GR engine#4GR-FSE|4GR-FSE]]'' [[V6]], 204&nbsp;hp (153&nbsp;kW), 6 speed automatic, rear wheel drive
* '''Australia''' (L/100&nbsp;km) – 'combined' 9.1, 'urban' 12.7, 'extra-urban' 7.0<ref name="greenvehicleguide.gov.au"/>
* '''Canada''' (L/100&nbsp;km) – 'combined' 9.6, 'city' 11.1, 'highway' 7.8<ref>{{cite web|url=http://www.lexus.ca/lexus/en/automobiles/is#intro_text|title=Lexus IS – Driving in every sense|website=Lexus Canada}}</ref>
* '''European Union''' (L/100&nbsp;km) – 'combined' 8.9, 'urban' 12.5, 'extra-urban' 6.9<ref name="lexus.de"/>
* '''United States''' (L/100&nbsp;km) – 'combined' 9.8, 'city' 11.2, 'highway' 8.1<ref name="fueleconomy.gov"/>

==Energy considerations==
{{More citations needed|section|date=November 2023}} 
Since the total force opposing the vehicle's motion (at constant speed) multiplied by the distance through which the vehicle travels represents the work that the vehicle's engine must perform, the study of fuel economy (the amount of energy consumed per unit of distance traveled) requires a detailed analysis of the forces that oppose a vehicle's motion. In terms of physics, Force = rate at which the amount of work generated (energy delivered) varies with the distance traveled, or:

:<math>F = \frac{dW}{ds} \propto \text{Fuel economy}</math>

Note: The amount of work generated by the vehicle's power source (energy delivered by the engine) would be exactly proportional to the amount of fuel energy consumed by the engine if the engine's efficiency is the same regardless of power output, but this is not necessarily the case due to the operating characteristics of the internal combustion engine.

For a vehicle whose source of power is a heat engine (an engine that uses heat to perform useful work), the amount of fuel energy that a vehicle consumes per unit of distance (level road) depends upon:

# The [[Energy efficiency of internal combustion engines|thermodynamic efficiency of the heat engine]];
# Frictional losses within the [[drivetrain]];
# [[Rolling resistance]] within the wheels and between the road and the wheels;
# Non-motive subsystems powered by the engine, such as [[Automobile air conditioning|air conditioning]], [[Internal combustion engine cooling|engine cooling]], and the [[Alternator (automotive)|alternator]];
# [[Drag (physics)|Aerodynamic drag]] from moving through air;
# Energy converted by [[Friction brake|frictional brakes]] into waste heat, or losses from [[Regenerative brake|regenerative braking]] in [[hybrid vehicle]]s;
# Fuel consumed while the engine is not providing power but still running, such as while [[Idle (engine)|idling]], minus the subsystem loads.<ref>{{cite web|url=http://onlinepubs.trb.org/onlinepubs/sr/sr286.pdf|title=TRANSPORTATION RESEARCH BOARD SPECIAL REPORT 286 TIRES AND PASSENGER VEHICLE FUEL ECONOMY, Transportation Research Board, National Academy of Sciences p.62-65 of pdf, p.39-42 of the report. Retrieved 22 October 2014.}}</ref>

[[File:Energy flows in car.svg|thumb|400px|Energy dissipation in city and highway driving for a mid-size gasoline-powered car]]
Ideally, a car traveling at a constant velocity on level ground in a vacuum with frictionless wheels could travel at any speed without consuming any energy beyond what is needed to get the car up to speed. Less ideally, any vehicle must expend energy on overcoming road load forces, which consist of aerodynamic drag, tire rolling resistance, and inertial energy that is lost when the vehicle is decelerated by friction brakes. With ideal [[regenerative braking]], the inertial energy could be completely recovered, but there are few options for reducing aerodynamic drag or rolling resistance other than optimizing the vehicle's shape and the tire design. Road load energy or the energy demanded at the wheels, can be calculated by evaluating the vehicle equation of motion over a specific driving cycle.<ref>[http://www.virtual-car.org/wheels/wheels-road-load-calculation.html Wheels, online road load, and MPG calculator]. Virtual-car.org (3 August 2009). Retrieved 21 September 2011.</ref> The vehicle powertrain must then provide this minimum energy to move the vehicle and will lose a large amount of additional energy in the process of converting fuel energy into work and transmitting it to the wheels. Overall, the sources of energy loss in moving a vehicle may be summarized as follows:
* [[Engine efficiency]] (20–30%), which varies with engine type, the mass of the automobile and its load, and engine speed (usually measured in [[Revolutions per minute|RPM]]).
* [[Aerodynamic drag]] force, which increases roughly by the [[drag equation|square of the car's speed]], but notes that [[Drag power|drag power goes by the cube of the car's speed]].
* [[Rolling friction]].
* Braking, although [[regenerative braking]] captures some of the energy that would otherwise be lost.
* Losses in the [[Transmission (mechanics)|transmission]]. [[Manual transmission]]s can be up to 94% efficient whereas older [[automatic transmission]]s may be as low as 70% efficient<ref>[http://www.sae.org/servlets/productDetail?PROD_TYP=PAPER&PROD_CD=1999-01-1259 An Overview of Current Automatic, Manual and Continuously Variable Transmission Efficiencies and Their Projected Future Improvements]. SAE.org (1 March 1999). Retrieved 21 September 2011.</ref> [[Automated manual transmission]]s, which have the same mechanical internals as conventional [[manual transmission]]s, will give the same efficiency as a pure manual gearbox plus the added bonus of intelligence selecting optimal shifting points, and/or automated clutch control but manual shifting, as with older [[semi-automatic transmission]]s.
* Air conditioning. The power required for the engine to turn the compressor decreases the fuel-efficiency, though only when in use. This may be offset by the reduced drag of the vehicle compared with driving with the windows down. The efficiency of AC systems gradually deteriorates due to dirty filters etc.; regular maintenance prevents this. The extra mass of the air conditioning system will cause a slight increase in fuel consumption.
* Power steering. The older hydraulic power steering systems are powered by a hydraulic pump constantly engaged to the engine. Power assistance required for steering is inversely proportional to the vehicle speed so the constant load on the engine from a hydraulic pump reduces fuel efficiency. More modern designs improve fuel efficiency by only activating the power assistance when needed; this is done by using either direct electrical power steering assistance or an electrically powered hydraulic pump.
* Cooling. The older cooling systems used a constantly engaged mechanical fan to draw air through the radiator at a rate directly related to the engine speed. This constant load reduces efficiency. More modern systems use electrical fans to draw additional air through the radiator when extra cooling is required.
* Electrical systems. Headlights, battery charging, active suspension, circulating fans, defrosters, media systems, speakers, and other electronics can also significantly increase fuel consumption, as the energy to power these devices causes an increased load on the alternator. Since alternators are commonly only 40–60% efficient, the added load from electronics on the engine can be as high as {{convert|3|hp}} at any speed including idle. In the FTP 75 cycle test, a 200-watt load on the alternator reduces fuel efficiency by 1.7&nbsp;mpg.<ref name=ieee/> Headlights, for example, consume 110 watts on low and up to 240 watts on high. These electrical loads can cause much of the discrepancy between real-world and EPA tests, which only include the electrical loads required to run the engine and basic climate control.
* Standby. The energy is needed to keep the engine running while it is not providing power to the wheels, i.e., when stopped, coasting or braking.

Fuel-efficiency decreases from electrical loads are most pronounced at lower speeds because most electrical loads are constant while engine load increases with speed. So at a lower speed, a higher proportion of engine [[horsepower]] is used by electrical loads. Hybrid cars see the greatest effect on fuel-efficiency from electrical loads because of this proportional effect.

===Fuel economy-boosting technologies===
{{Main|Fuel saving devices}}

====Engine-specific technology====
{| class="wikitable"
|-
!Type
!Technology
!Explanation
!Inventor
!Notes
|-
!Engine cycle
|Replacing petrol engines with diesel engines
|Reduces brake specific fuel consumption at lower RPM
|Herbert Akroyd Stuart
|
|-
!Engine combustion strategies
|Electronic control of the cooling system
|Optimizes engine running temperature
|
|
|-
!
|Stratified Charge combustion
|Injects fuel into cylinder just before ignition, increasing compression ratio
|
|For use in petrol engines
|-
!
|Lean burn combustion
|Increases air/fuel ratio to reduce throttling losses
|Chrysler
|https://www.youtube.com/watch?v=KnNX6gtDyhg
|-
!
|Cooled [[exhaust gas recirculation]] (petrol)
|Reduces throttling losses, heat rejection, chemical dissociation, and specific heat ratio
|
|
|-
!
|Cooled exhaust gas recirculation (diesel)
|Lowers peak combustion temperatures
|
|
|-
!
|[[Atkinson cycle]]
|Lengthens power stroke to achieve greater thermal efficiency
|James Atkinson
|[[File:Atkinson Gas Engine Animated.gif|thumb|Atkinson cycle]]
|-
!
|[[Variable valve timing]] and [[variable valve lift]]
|Alters valve lift timing and height for precise control over intake and exhaust
|
|William Howe and William Williams ([[Robert Stephenson and Company]]) invented the first [[Stephenson valve gear|variable timing valve]]
|-
!
|Variable geometry turbocharging
|Optimizes airflow with adjustable vanes to regulate turbocharger's air intake and eliminate turbo lag
|Garrett ([[Honeywell Turbo Technologies|Honeywell]])
|[[File:VNT Vanes Open.jpg|thumb|VNT Vanes Open]]
|-
!
|Twincharging
|Combines a supercharger with a turbocharger to eliminate turbo lag
|Lancia
|For use in small-displacement engines
|-
!
|Gasoline direct injection (GDI) engines
|Allows for stratified fuel charge and ultra-lean burn
|Leon Levavasseur
|
|-
!
|[[Turbocharged Direct Injection]] diesel engines
|Combines direct injection with a turbocharger
|Volkswagen
|
|-
!
|Common rail direct injection
|Increases injection pressure
|Robert Huber
|
|-
!
|Piezoelectric diesel injectors
|Uses multiple injections per engine cycle for increased precision
|
|
|-
!
|Cylinder management
|Shuts off individual cylinders when their power output is not needed
|
|
|-
!
|HCCI (Homogeneous Charge Compression Ignition) combustion
|Allows leaner and higher compression burn
|
|https://www.youtube.com/watch?v=B8CnYljXAS0
|-
!
|[[Scuderi engine]]
|Eliminates recompression losses
|Carmelo J. Scuderi
|[[File:Scuderi Split Cycle Engine - Cycle.gif|thumb|upright|100px|Scuderi engine]]
|-
!
|Compound engines (6-stroke engine or turbo-compound engine)
|Recovers exhaust energy
|
|
|-
!
|Two-stroke diesel engines
|Increases power to weight ratio
|Charles F. Kettering
|
|-
!
|High-efficiency gas turbine engines
|Increases power to weight ratio
|
|
|-
!
|Turbosteamer
|Uses heat from the engine to spin a mini turbine to generate power
|Raymond Freymann (BMW)
|
|-
!
|Stirling hybrid battery vehicle
|Increases thermal efficiency
|Still largely theoretical, although prototypes have been produced by Dean Kamen
|
|-
!
|Time-optimized piston path
|Captures energy from gases in the cylinders at their highest temperatures
|
|
|-
!Engine internal losses
|Downsized engines with a supercharger or a turbocharger
|Reduces engine displacement while maintaining sufficient torque
|Saab, starting with the 99 in 1978.
|[[File:2014-Global-Turbo-Forecast.png|thumb|2014-Global-Turbo-Forecast]]
|-
!
|Lower-friction lubricants (engine oil, transmission fluid, axle fluid)
|Reduces energy lost to friction
|
|
|-
!
|Lower viscosity engine oils
|Reduces hydrodynamic friction and energy required to circulate
|
|
|-
!
|Variable displacement oil pump
|Avoids excessive flow rate at high engine speed
|
|
|-
!
|Electrifying engine accessories (water pump, power steering pump, and air conditioner compressor)
|Sends more engine power to the transmission or reduces the fuel required for the same traction power
|
|
|-
!
|Roller type cam, low friction coating on piston skirt and optimizing load-bearing surface, e.g. camshaft bearing and connective rods.
|Reduces engine frictions
|
|
|-
!Engine running conditions
|Coolant additives
|Increases the thermal efficiency of the cooling system
|
|
|-
!
|Increasing the number of gearbox ratios in manual gearboxes
|Lowers the engine rpm at cruise
|
|
|-
!
|Reducing the volume of water-based cooling systems
|Engine reaches its efficient operating temperature more quickly
|
|
|-
!
|[[Start-stop system]]
|Automatically shuts off engine when vehicle is stopped, reducing idle time
|
|
|-
!
|Downsized engines with an electric drive system and battery
|Avoids low-efficiency idle and power conditions
|
|
|}

====Other vehicle technologies====
{| class="wikitable"
|-
!Type
!Technology
!Explanation
!Inventor
!Notes
|-
!Transmission losses
|Continuously variable transmission (CVT)
|Enables engine to run at its most efficient RPM
|
|For use in automatic gearboxes
|-
!
|Locking torque converters in automatic transmissions
|Reduces slip and power losses in the converter
|
|
|-
!Rolling resistance
|Lighter construction materials (aluminum, fiberglass, plastic, high-strength steel, and carbon fiber)
|Reduces vehicle weight
|
|
|-
!
|Increasing tire pressure
|Lowers tire deformation underweight
|
|
|-
!
|Replacing tires with low rolling resistance (LRR) models
|Lowers rolling resistance<ref>[[Low-rolling resistance tires]]</ref>
|
|
|-
!Series parallel hybrid
|Using an electric motor for the base power and an IC engine for assists and boosts, when needed
|Decreases fuel consumption by running the petrol engine only when needed, in this way also environmentally friendly.
|TRW
|
|-
!Energy saving
|Lighter materials for moving parts (pistons, crankshaft, gears, and alloy wheels)
|Reduces the energy required to move parts
|
|
|-
!
|[[Regenerative braking]]
|Captures kinetic energy while braking
|Louis Antoine Kriéger
|For use in hybrid or electric vehicles
|-
!
|Recapturing waste heat from the exhaust system
|Converts heat energy into electricity using [[thermoelectric cooling]]
|[[Jean Charles Athanase Peltier]]
|
|-
!
|Regenerative shock absorbers
|Recaptures wasted energy in the vehicle suspension<ref>
{{cite web
 | last = Chandler
 | first = David
 | title = More power from bumps in the road
 | date = 9 February 2009
| access-date =8 October 2009
| url = http://web.mit.edu/newsoffice/2009/shock-absorbers-0209.html
}}</ref>
|Levant Power
|
|-
!Traffic management
|Active highway management
|Matches speed limits and vehicles allowed to join motorways with traffic density to maintain traffic throughput
|
|
|-
!
|Vehicle electronic control systems that automatically maintain distances between vehicles on motorways
|Reduces ripple back braking and consequent re-acceleration
|
|
|}

====Future technologies====
Technologies that may improve fuel efficiency, but are not yet on the market, include:
* [[HCCI]] (Homogeneous Charge Compression Ignition) combustion
* [[Scuderi engine]]
* [[Compound engine]]s
* [[Two-stroke diesel engine]]s
* High-efficiency [[gas turbine engine]]s
* BMW's [[Turbosteamer]] – using the heat from the engine to spin a mini turbine to generate power
* Vehicle electronic control systems that automatically maintain distances between vehicles on motorways/freeways that reduce ''ripple back braking'', and consequent re-acceleration.
* Time-optimized piston path, to capture energy from hot gases in the cylinders when they are at their highest temperatures{{Citation needed|date=November 2009}}
* sterling hybrid battery vehicle
Many [[Aftermarket fuel economy device|aftermarket consumer products]] exist that are purported to increase fuel economy; many of these claims have been discredited. In the United States, the Environmental Protection Agency maintains a list of devices that have been tested by independent laboratories and makes the test results available to the public.<ref>[http://www.epa.gov/otaq/consumer/reports.htm Gas Saving and Emission Reduction Devices Evaluation | Cars and Light Trucks | US EPA]. Epa.gov. Retrieved 21 September 2011.</ref>

===Fuel economy maximizing behaviors===
{{Main|Fuel economy-maximizing behaviors}}
Governments, various environmentalist organizations, and companies like [[Toyota]] and [[Shell Oil Company]] have historically urged drivers to maintain adequate air pressure in [[tire]]s and careful acceleration/deceleration habits. Keeping track of fuel efficiency stimulates fuel economy-maximizing behavior.<ref>https://onfuel.appspot.com keep track of fuel efficiency</ref>

A five-year partnership between [[Michelin]] and [[Anglian Water]] shows that 60,000 liters of fuel can be saved on tire pressure. The Anglian Water fleet of 4,000 vans and cars are now lasting their full lifetime. This shows the impact that tire pressures have on the fuel efficiency.<ref>{{cite web|title = Anglian Water spot on with pressure test|url = http://www.tyrepress.com/2015/10/anglian-water-spot-on-with-pressure-test/|website = Tyrepress|access-date = 30 October 2015|date = 29 October 2015}}</ref>

===Fuel economy as part of quality management regimes===
[[Environmental management]] systems [[Eco-Management and Audit Scheme|EMAS]], as well as good fleet management, includes record-keeping of the fleet fuel consumption. Quality management uses those figures to steer the measures acting on the fleets. This is a way to check whether procurement, driving, and maintenance in total have contributed to changes in the fleet's overall consumption.

==Fuel economy standards and testing procedures==
{|class="wikitable"
|+ Gasoline new passenger car fuel efficiency
|-
! rowspan=2 | Country
! rowspan=2 | 2004 average
! colspan=4 | Requirement
|-
! 2004 || 2005 || 2008 || Later
|-
| People's Republic of China<ref>[http://www.treehugger.com/files/2005/07/chinese_fuel_ec.php Chinese Fuel Economy Laws]. Treehugger.com. Retrieved 21 September 2011.</ref> || || || 6.9&nbsp;L/100&nbsp;km || 6.9&nbsp;L/100&nbsp;km || 6.1&nbsp;L/100&nbsp;km
|-
| [[#United States|United States]] || 24.6&nbsp;mpg (9.5&nbsp;L/100&nbsp;km) (cars and trucks)* || 27&nbsp;mpg (8.7&nbsp;L/100&nbsp;km) (cars only)* || || || 35&nbsp;mpg (6.7&nbsp;L/100&nbsp;km) (Model Year 2020, cars & light trucks)
|-
| [[#Europe|European Union]] || || || || || 4.1&nbsp;L/100&nbsp;km (2020, [[#Europe|NEDC]])
|-
| [[#Japan|Japan]]<ref name=pew>[http://www.pewclimate.org/docUploads/Fuel%20Economy%20and%20GHG%20Standards_010605_110719.pdf Comparison of Passenger Vehicle Fuel Economy and GHG Emission Standards Around the World at Pew Center on Global Climate Change] {{Webarchive|url=https://web.archive.org/web/20080413221041/http://www.pewclimate.org/docUploads/Fuel%20Economy%20and%20GHG%20Standards_010605_110719.pdf |date=13 April 2008 }}. (PDF). Retrieved 21 September 2011.</ref>|| || || || ||6.7&nbsp;L/100&nbsp;km [[#CAFE standards|CAFE]] eq (2010)
|-
| [[#Australia|Australia]]<ref name=pew /> || 8.08&nbsp;L/100&nbsp;km CAFE eq (2002) || none || || || none (as of March 2019)<ref>{{Cite news | url=https://www.theguardian.com/environment/2019/mar/31/government-accused-australia-failure-cut-vehicle-emissions |title = 'Woefully dirty': Government accused over Australia's failure to cut vehicle emissions|newspaper = The Guardian|date = 30 March 2019|last1 = Cox|first1 = Lisa}}</ref>
|} <!-- THIS TABLE IS INCOMPLETE, PLEASE HELP FILL IT IN! -->
<nowiki>* highway ** combined</nowiki>

===Australia===
From October 2008, all new cars had to be sold with a sticker on the windscreen showing the fuel consumption and the CO<sub>2</sub> emissions.<ref>[http://www.infrastructure.gov.au/roads/environment/index.aspx Vehicles & the Environment]. Infrastructure.gov.au. Retrieved 21 September 2011.</ref> Fuel consumption figures are expressed as ''urban'', ''extra urban'' and ''combined'', measured according to [[ECE Regulations]] 83 and 101 – which are the based on the [[New European Driving Cycle|European driving cycle]]; previously, only the ''combined'' number was given.

Australia also uses a star rating system, from one to five stars, that combines greenhouse gases with pollution, rating each from 0 to 10 with ten being best. To get 5 stars a combined score of 16 or better is needed, so a car with a 10 for economy (greenhouse) and a 6 for emission or 6 for economy and 10 for emission, or anything in between would get the highest 5 star rating.<ref>[https://web.archive.org/web/20110716024739/http://www.greenvehicleguide.gov.au/GVGPublicUI/home.aspx Information on Green Vehicle Guide Ratings and Measurement]. Australian Department of Infrastructure and Transport</ref> The lowest rated car is the [[SsangYong Korando|Ssangyong Korrando]] with automatic transmission, with one star, while the highest rated was the Toyota Prius hybrid. The Fiat 500, Fiat Punto and Fiat Ritmo as well as the Citroen C3 also received 5 stars.<ref>[http://www.greenvehicleguide.gov.au/ Green Vehicle Guide] {{Webarchive|url=https://web.archive.org/web/20060422230409/http://www.greenvehicleguide.gov.au/ |date=22 April 2006 }}. Green Vehicle Guide. Retrieved 21 September 2011.</ref> The greenhouse rating depends on the fuel economy and the type of fuel used. A greenhouse rating of 10 requires 60 or less grams of CO<sub>2</sub> per km, while a rating of zero is more than 440 g/km CO<sub>2</sub>. The highest greenhouse rating of any 2009 car listed is the Toyota Prius, with 106&nbsp;g/km CO<sub>2</sub> and {{convert|4.4|L/100 km|abbr=on }}. Several other cars also received the same rating of 8.5 for greenhouse. The lowest rated was the Ferrari 575 at 499&nbsp;g/km CO<sub>2</sub> and {{convert|21.8|L/100 km|abbr=on }}.<!--The Ferrari is incorrectly given a rating of 0.5 instead of zero.--> The Bentley also received a zero rating, at 465&nbsp;g/km CO<sub>2</sub>. The best fuel economy of any year is the 2004–2005 [[Honda Insight]], at {{convert|3.4|L/100 km|abbr=on }}.

===Canada===
Vehicle manufacturers follow a controlled laboratory testing procedure to generate the fuel consumption data that they submit to the Government of Canada. This controlled method of fuel consumption testing, including the use of standardized fuels, test cycles and calculations, is used instead of on-road driving to ensure that all vehicles are tested under identical conditions and that the results are consistent and repeatable.

Selected test vehicles are "run in" for about 6,000&nbsp;km before testing. The vehicle is then mounted on a chassis dynamometer programmed to take into account the aerodynamic efficiency, weight and rolling resistance of the vehicle. A trained driver runs the vehicle through standardized driving cycles that simulate trips in the city and on the highway. Fuel consumption ratings are derived from the emissions generated during the driving cycles.<ref name="nrcan.gc.ca">{{cite web|url=https://www.nrcan.gc.ca/energy/efficiency/transportation/cars-light-trucks/buying/7495|title=5-cycle testing|website=nrcan.gc.ca|date=30 April 2018}}</ref>

THE 5 CYCLE TEST:

# The '''city test''' simulates urban driving in stop-and-go traffic with an average speed of 34&nbsp;km/h and a top speed of 90&nbsp;km/h. The test runs for approximately 31 minutes and includes 23 stops. The test begins from a cold engine start, which is similar to starting a vehicle after it has been parked overnight during the summer. The final phase of the test repeats the first eight minutes of the cycle but with a hot engine start. This simulates restarting a vehicle after it has been warmed up, driven and then stopped for a short time. Over five minutes of test time are spent idling, to represent waiting at traffic lights. The ambient temperature of the test cell starts at 20&nbsp;°C and ends at 30&nbsp;°C.
# The '''highway test''' simulates a mixture of open highway and rural road driving, with an average speed of 78&nbsp;km/h and a top speed of 97&nbsp;km/h. The test runs for approximately 13 minutes and does not include any stops. The test begins from a hot engine start. The ambient temperature of the test cell starts at 20&nbsp;°C and ends at 30&nbsp;°C.
# In the '''cold temperature operation test''', the same driving cycle is used as in the standard '''city test''', except that the ambient temperature of the test cell is set to −7&nbsp;°C.
# In the '''air conditioning test''', the ambient temperature of the test cell is raised to 35&nbsp;°C. The vehicle's climate control system is then used to lower the internal cabin temperature. Starting with a warm engine, the test averages 35&nbsp;km/h and reaches a maximum speed of 88&nbsp;km/h. Five stops are included, with idling occurring 19% of the time.
# The '''high speed/quick acceleration test''' averages 78&nbsp;km/h and reaches a top speed of 129&nbsp;km/h. Four stops are included and brisk acceleration maximizes at a rate of 13.6&nbsp;km/h per second. The engine begins warm and air conditioning is not used. The ambient temperature of the test cell is constantly 25&nbsp;°C.

Tests 1, 3, 4, and 5 are averaged to create the city driving fuel consumption rate.

Tests 2, 4, and 5 are averaged to create the highway driving fuel consumption rate.<ref name="nrcan.gc.ca"/>

===Europe===
[[File:Irish Car CO2 Label.svg|thumb|right|Irish fuel economy label]]
{{main|New European Driving Cycle}}

{{Update section|date=September 2018|reason=[[Worldwide harmonized Light vehicles Test Procedure]] WLTP replaced NEDC for vehicles certified after September 2018|inaccurate=yes}}In the European Union, passenger vehicles are commonly tested using two drive cycles, and corresponding fuel economies are reported as "urban" and "extra-urban", in liters per 100&nbsp;km and (in the UK) in miles per imperial gallon.

The urban economy is measured using the test cycle known as ECE-15, first introduced in 1970 by EC Directive 70/220/EWG and finalized by EEC Directive 90/C81/01 in 1999. It simulates a 4,052&nbsp;m (2.518&nbsp;mile) urban trip at an average speed of 18.7&nbsp;km/h (11.6&nbsp;mph) and at a maximum speed of 50&nbsp;km/h (31&nbsp;mph).

The extra-urban driving cycle or EUDC lasts 400 seconds (6&nbsp;minutes 40 seconds) at an average speed 62.6&nbsp;km/h (39&nbsp;mph) and a top speed of 120&nbsp;km/h (74.6&nbsp;mph).<ref>[http://herkules.oulu.fi/isbn9514269543/html/x787.html Vehicle test cycles]. Herkules.oulu.fi. Retrieved 21 September 2011.</ref>

EU fuel consumption numbers are often considerably lower than corresponding US EPA test results for the same vehicle. For example, the 2011 [[Honda CR-Z]] with a six-speed manual transmission is rated 6.1/4.4 L/100&nbsp;km in Europe<ref>{{Cite web|url=https://www.honda.de/cars/world-of-honda/news-events.html|title=News & Events|website=www.honda.de|accessdate=2 May 2023}}</ref> and 7.6/6.4 L/100&nbsp;km (31/37 mpg ) in the United States.<ref>{{Cite web|url=http://autos.msn.com/research/vip/Spec_Glance.aspx?year=2011&make=Honda&model=CR-Z|title=2011 Honda CR-Z Specs and Features|accessdate=2 May 2023}}</ref>

In the European Union advertising has to show [[carbon dioxide]] (CO<sub>2</sub>)-emission and fuel consumption data in a clear way as described in the UK Statutory Instrument 2004 No 1661.<ref>[http://www.vca.gov.uk/additional/files/fcb--co2/enforcement-on-advertising/vca061.pdf Guidance notes and examples] {{Webarchive|url=https://web.archive.org/web/20080413221042/http://www.vca.gov.uk/additional/files/fcb--co2/enforcement-on-advertising/vca061.pdf |date=13 April 2008 }}. (PDF). Retrieved 21 September 2011.</ref> Since September 2005 a color-coded "Green Rating" sticker has been available in the UK, which rates fuel economy by CO<sub>2</sub> emissions: A: &lt;= 100 g/km, B: 100–120, C: 121–150, D: 151–165, E: 166–185, F: 186–225, and G: 226+. Depending on the type of fuel used, for gasoline A corresponds to about {{convert|4.1|L/100 km|abbr=on|lk=off }} and G about {{convert|9.5|L/100 km|abbr=on|lk=off }}.<ref>[http://www.dft.gov.uk/actonco2/index.php?q=fuel_economy_sticker Fuel Economy Label] {{webarchive|url=https://web.archive.org/web/20080814112511/http://www.dft.gov.uk/ActOnCO2/index.php?q=fuel_economy_sticker |date=14 August 2008 }}. Dft.gov.uk. Retrieved 21 September 2011.</ref> Ireland has a very similar label, but the ranges are slightly different, with A: <= 120 g/km, B: 121–140, C: 141–155, D: 156–170, E: 171–190, F: 191–225, and G: 226+.<ref>[http://www.environ.ie/en/Environment/Atmosphere/ClimateChange/VehicleLabelling/ Vehicle Labelling] {{webarchive|url= https://web.archive.org/web/20080707012035/http://www.environ.ie/en/Environment/Atmosphere/ClimateChange/VehicleLabelling/ |date=7 July 2008 }}. Environ.ie (1 July 2008). Retrieved 21 September 2011.</ref> From 2020, EU requires manufacturers to average 95 g/km {{CO2}} emission or less, or pay an [[Fine (penalty)|excess emissions premium]].<ref>{{cite web |title=Regulation (EU) 2019/631 of the European Parliament and of the Council of 17 April 2019 setting CO2 emission performance standards for new passenger cars and for new light commercial vehicles, and repealing Regulations (EC) No 443/2009 and (EU) No 510/2011 (Text with EEA relevance.) |url=https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32019R0631 |publisher=[[European Union]] |language=en |date=25 April 2019 |quote=Annex 1, Part A.6 NEDC2020, Fleet Target is 95 g/km. (45) Manufacturers whose average specific emissions of CO2 exceed those permitted under this Regulation should pay an excess emissions premium with respect to each calendar year.}}</ref>

In the UK the ASA (Advertising standards agency) have claimed that fuel consumption figures are misleading. Often the case with European vehicles as the MPG (miles per gallon) figures that can be advertised are often not the same as "real world" driving.

The ASA have said that car manufacturers can use "cheats" to prepare their vehicles for their compulsory fuel efficiency and emissions tests in a way set out to make themselves look as "clean" as possible. This practice is common in gasoline and diesel vehicle tests, but hybrid and electric vehicles are not immune as manufacturers apply these techniques to fuel efficiency.

Car experts{{who|date=November 2015}} also assert that the ''official'' MPG figures given by manufacturers do not represent the ''true'' MPG values from real-world driving.<ref>{{cite web|title=Why the EC figures do not represent true MPG |url=http://www.honestjohn.co.uk/realmpg/why-are-the-ec-figures-so-optimistic-true-mpg/ |work=Honest John |access-date=14 November 2015 }}</ref> Websites have been set up to show the real-world MPG figures, based on crowd-sourced data from real users, vs the official MPG figures.<ref>{{cite web|title=Real Life Fuel Economy (MPG) Register |url=http://www.honestjohn.co.uk/realmpg/ |work=Honest John |access-date=14 November 2015 }}</ref>

The major loopholes in the current EU tests allow car manufacturers a number of "cheats" to improve results. Car manufacturers can:
* Disconnect the alternator, thus no energy is used to recharge the battery;
* Use special lubricants that are not used in production cars, in order to reduce friction;
* Turn off all electrical gadgets i.e. Air Con/Radio;
* Adjust brakes or even disconnect them to reduce friction;
* Tape up cracks between body panels and windows to reduce air resistance;
* Remove Wing mirrors.<ref>{{cite web|url=http://www.carsandgarages.co.uk/news/29-ASA-says-fuel-consumption-figures-are-mis |title=Cars and Garages: Diagnose Problems, Estimate Costs & Find Garages|website=carsandgarages.co.uk}}</ref>

According to the results of a 2014 study by the [[International Council on Clean Transportation]] (ICCT), the gap between official and real-world fuel-economy figures in Europe has risen to about 38% in 2013 from 10% in 2001. The analysis found that for private cars, the difference between on-road and official {{CO2}} values rose from around 8% in 2001 to 31% in 2013, and 45% for company cars in 2013. The report is based on data from more than half a million private and company vehicles across Europe. The analysis was prepared by the ICCT together with the [[Netherlands Organization for Applied Scientific Research]] (TNO), and the German Institut für Energie- und Umweltforschung Heidelberg (IFEU).<ref>{{cite web|url=http://www.greencarcongress.com/2014/09/20140928-icct.html |title=ICCT: gap between official and real-world fuel economy figures in Europe reaches ~38%; call to implement WLTP ASAP|author=Mike Millikin|publisher=[[Green Car Congress]]|date=28 September 2014|access-date=28 September 2014}}</ref>

In 2018 update of the ICCT data the difference between the official and real figures was again 38%.<ref>[https://www.theicct.org/publications/laboratory-road-2018-update From laboratory to road: A 2018 update] ICCT, 2019</ref>

===Japan===
The evaluation criteria used in Japan reflects driving conditions commonly found, as the typical Japanese driver does not drive as fast as other regions internationally ([[Speed limits in Japan]]).

====10–15 mode====
The 10–15 mode [[driving cycle]] test is the official fuel economy and emission certification test for new light duty vehicles in Japan. Fuel economy is expressed in km/L (kilometers per liter) and emissions are expressed in g/km. The test is carried out on a [[dynamometer]] and consist of 25 tests which cover idling, acceleration, steady running and deceleration, and simulate typical Japanese urban and/or expressway driving conditions. The running pattern begins with a warm start, lasts for 660 seconds (11 minutes) and runs at speeds up to {{convert|70|km/h|mi/h|1|abbr=on}}.<ref name=JapTest01>{{cite web|url=http://www.jama-english.jp/europe/news/2009/no_2/peternunn.html|title=From 10•15 to JC08: Japan's new economy formula|author=[[Japan Automobile Manufacturers Association]] (JAMA)|publisher=News from JAMA|year=2009|access-date=9 April 2012}} ''Issue No. 2, 2009''.</ref><ref name=JapTest02>{{cite web|url=http://www.dieselnet.com/standards/cycles/jp_10-15mode.php|title=Japanese 10–15 Mode|publisher=Diesel.net|access-date=9 April 2012}}</ref> The distance of the cycle is {{convert|6.34|km|mi|1|abbr=on}}, average speed of {{convert|25.6|km/h|mi/h|1|abbr=on}}, and duration 892 seconds (14.9 minutes), including the initial 15 mode segment.<ref name=JapTest02/>

====JC08====
A new more demanding test, called the JC08, was established in December 2006 for Japan's new standard that goes into effect in 2015, but it is already being used by several car manufacturers for new cars. The JC08 test is significantly longer and more rigorous than the 10–15 mode test. The running pattern with JC08 stretches out to 1200 seconds (20 minutes), and there are both cold and warm start measurements and top speed is {{convert|82|km/h|mi/h|1|abbr=on}}. The economy ratings of the JC08 are lower than the 10–15 mode cycle, but they are expected to be more real world.<ref name=JapTest01/> The [[Toyota Prius]] became the first car to meet Japan's new 2015 Fuel Economy Standards measured under the JC08 test.<ref>{{cite web|url=http://www.greencarcongress.com/2007/08/prius-certified.html|title=Prius Certified to Japanese 2015 Fuel Economy Standards with JC08 Test Cycle|publisher=[[Green Car Congress]]|date=11 August 2007|access-date=9 April 2012}}</ref>

===New Zealand===
Starting on 7 April 2008 all cars of up to 3.5 tonnes GVW sold other than private sale need to have a fuel economy sticker applied (if available) that shows the rating from one half star to six stars with the most economic cars having the most stars and the more fuel hungry cars the least, along with the fuel economy in L/100&nbsp;km and the estimated annual fuel cost for driving 14,000&nbsp;km (at present fuel prices). The stickers must also appear on vehicles to be leased for more than 4&nbsp;months. All new cars currently rated range from {{convert|6.9|L/100 km|abbr=on|lk=off }} to {{convert|3.8|L/100 km|abbr=on|lk=off }} and received respectively from 4.5 to 5.5 stars.<ref>{{Cite web|url=http://www.eeca.govt.nz/transport/vehicle-fuel-economy/faqs.htm|archiveurl=https://web.archive.org/web/20080710061145/http://www.eeca.govt.nz/transport/vehicle-fuel-economy/faqs.htm|url-status=dead|title=Vehicle Fuel Economy Labelling – FAQs|archivedate=10 July 2008|accessdate=2 May 2023}}</ref>

===Saudi Arabia===

The [[Kingdom of Saudi Arabia]] announced new light-duty vehicle fuel economy standards in November 2014 which became effective 1 January 2016 and will be fully phased in by 1 January 2018 ([[Saudi Standards, Metrology and Quality Organization|Saudi Standards]] regulation SASO-2864). A review of the targets will be carried by December 2018, at which time targets for 2021–2025 will be set.

===United States===
[[File:Motor vehicle efficiency.png|thumb|right|Motor vehicle fuel economy from 1949 to 2021]]

====US Energy Tax Act====
{{Main|Energy Tax Act}}
The [[Energy Tax Act]] of 1978<ref>[http://www.fueleconomy.gov/feg/info.shtml#guzzler Frequently Asked Questions]. Fueleconomy.gov. Retrieved 21 September 2011.</ref> in the US established a gas guzzler tax on the sale of new model year vehicles whose fuel economy fails to meet certain statutory levels. The tax applies only to cars (not trucks) and is collected by the [[Internal Revenue Service|IRS]]. Its purpose is to discourage the production and purchase of fuel-inefficient vehicles. The tax was phased in over ten years with rates increasing over time. It applies only to manufacturers and importers of vehicles, although presumably some or all of the tax is passed along to automobile consumers in the form of higher prices. Only new vehicles are subject to the tax, so no tax is imposed on used car sales. The tax is graduated to apply a higher tax rate for less-fuel-efficient vehicles. To determine the tax rate, manufacturers test all the vehicles at their laboratories for fuel economy. The US [[United States Environmental Protection Agency|Environmental Protection Agency]] confirms a portion of those tests at an EPA lab.

In some cases, this tax may apply only to certain variants of a given model; for example, the 2004–2006 [[Holden Monaro#Pontiac GTO|Pontiac GTO]] (captive import version of the [[Holden Monaro]]) did incur the tax when ordered with the four-speed automatic transmission, but did not incur the tax when ordered with the six-speed manual transmission.<ref>{{cite web |url=http://www.cars.com/pontiac/gto/2005/reviews/?revid=47269 |title=2005 Pontiac GTO |date=28 April 2005 |author=Steven Cole Smith |publisher=Orlando Sentinel via Cars.com |access-date=21 February 2011 |archive-url=https://web.archive.org/web/20150511195355/http://www.cars.com/pontiac/gto/2005/reviews/?revid=47269 |archive-date=11 May 2015 |url-status=dead }}</ref>

====EPA testing procedure through 2007====
[[File:Uddsdds.gif|thumb|200px|The "city" or Urban Dynamometer Driving Schedule (UDDS) used in the EPA Federal Test Procedure]] [[File:Hwfetdds.gif|thumb|200px|The Highway Fuel Economy Driving Cycle (HWFET) used in the EPA Federal Test Procedure]]
Two separate fuel economy tests simulate city driving and highway driving: the "city" driving program or Urban Dynamometer Driving Schedule or (UDDS) or [[FTP-72]] is defined in {{CodeFedReg|40|86|prefix=App|I}} and consists of starting with a cold engine and making 23 stops over a period of 31&nbsp;minutes for an average speed of 20&nbsp;mph (32&nbsp;km/h) and with a top speed of 56&nbsp;mph (90&nbsp;km/h).

The "highway" program or Highway Fuel Economy Driving Schedule (HWFET) is defined in {{CodeFedReg|40|600|prefix=App|I}} and uses a warmed-up engine and makes no stops, averaging 48&nbsp;mph (77&nbsp;km/h) with a top speed of 60&nbsp;mph (97&nbsp;km/h) over a {{convert|10|mi|km|adj=on}} distance. A weighted average of city (55%) and highway (45%) fuel economies is used to determine the combined rating and guzzler tax.<ref name="EPA cycles">{{cite web|title=Dynamometer Driver's Aid |url=http://www.epa.gov/nvfel/testing/dynamometer.htm |publisher=US EPA |access-date=11 January 2011 |url-status=dead |archive-url=https://web.archive.org/web/20140330111359/http://www.epa.gov/nvfel/testing/dynamometer.htm |archive-date=30 March 2014 }}</ref><ref>[http://auto.howstuffworks.com/28004-epa-fuel-economy-explained1.htm How the EPA Tests and Rates Fuel Economy]. Auto.howstuffworks.com (7 September 2005). Retrieved 21 September 2011.</ref><ref>[https://fueleconomy.gov/feg/label/learn-more-gasoline-label.shtml Gasoline Vehicles: Learn More About the Label]. Retrieved 10 July 2020.</ref> This rating is what is also used for light-duty vehicle [[corporate average fuel economy]] regulations.

The procedure has been updated to [[FTP-75]], adding a "hot start" cycle which repeats the "cold start" cycle after a 10-minute pause.

Because EPA figures had almost always indicated better efficiency than real-world fuel-efficiency, the EPA has modified the method starting with 2008. Updated estimates are available for vehicles back to the 1985 model year.<ref name="EPA cycles"/><ref>[http://www.fueleconomy.gov/feg/findacar.htm Find a Car 1985 to 2009]. Fueleconomy.gov. Retrieved 21 September 2011.</ref>
{{clear}}

====EPA testing procedure: 2008 and beyond====
[[File:Fuel economy label EPA 2008.jpg|thumb|right|2008 [[Monroney sticker]] highlights fuel economy.]]
US EPA altered the testing procedure effective MY2008 which adds three new [[FTP-75#Supplemental tests|Supplemental Federal Test Procedure]] (SFTP) tests to include the influence of higher driving speed, harder acceleration, colder temperature and air conditioning use.<ref name=2008epa_test>{{cite web|title=2008 Ratings Changes|url=http://www.fueleconomy.gov/feg/fe_test_schedules.shtml|publisher=US EPA|access-date=17 April 2013}}</ref>

SFTP US06 is a high speed/quick acceleration loop that lasts 10&nbsp;minutes, covers {{convert|8|mi|km}}, averages {{convert|48|mi/h|km/h|abbr=on}} and reaches a top speed of {{convert|80|mi/h|km/h|abbr=on}}. Four stops are included, and brisk acceleration maximizes at a rate of {{convert|8.46|mi/h|km/h|abbr=on}} per second. The engine begins warm and air conditioning is not used. Ambient temperature varies between {{convert|68|°F|°C}} to {{convert|86|°F|°C}}.

SFTO SC03 is the air conditioning test, which raises ambient temperatures to {{convert|95|°F|°C}}, and puts the vehicle's climate control system to use. Lasting 9.9&nbsp;minutes, the {{convert|3.6|mi|km|adj=on}} loop averages {{convert|22|mi/h|km/h|abbr=on}} and maximizes at a rate of {{convert|54.8|mi/h|km/h|abbr=on}}. Five stops are included, idling occurs 19 percent of the time and acceleration of 5.1&nbsp;mph per second is achieved. Engine temperatures begin warm.

Lastly, a cold temperature cycle uses the same parameters as the current city loop, except that ambient temperature is set to {{convert|20|°F|°C}}.

EPA tests for fuel economy do not include electrical load tests beyond climate control, which may account for some of the discrepancy between EPA and real world fuel-efficiency. A 200&nbsp;W electrical load can produce a 0.4&nbsp;km/L (0.94&nbsp;mpg) reduction in efficiency on the FTP 75 cycle test.<ref name=ieee>[http://www.spectrum.ieee.org/print/1420 Automotive Electrical Systems Circa 2005] {{Webarchive|url=https://web.archive.org/web/20090203012939/http://www.spectrum.ieee.org/print/1420 |date=3 February 2009 }}. Spectrum.ieee.org. Retrieved 21 September 2011.</ref>

Beginning with model year 2017 the calculation method changed to improve the accuracy of the estimated 5-cycle city and highway fuel economy values derived from just the FTP and HFET tests, with lower uncertainty for fuel efficient vehicles.<ref>{{cite web|author=US EPA United States Environmental Protection Agency |url=https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=35113&flag=1 |title=Basic Search |publisher=Iaspub.epa.gov |accessdate=1 September 2022}}</ref>

====Electric vehicles and hybrids====
[[File:Chevy Volt EPA Fuel Economy Official Label.png|thumb|left|2010 [[Monroney sticker]] for a [[plug-in hybrid]] showing fuel economy in [[all-electric mode]] and gasoline-only mode]]
Following the efficiency claims made for vehicles such as [[Chevrolet Volt]] and [[Nissan Leaf]], the [[National Renewable Energy Laboratory]] recommended to use EPA's new vehicle fuel efficiency formula that gives different values depending on fuel used.<ref>Roth, Dan. (1 October 2009) [http://www.autoblog.com/2009/10/01/report-epa-planning-to-address-outlandish-fuel-economy-claims-o/ REPORT: EPA planning to address outlandish fuel economy claims of electric cars]. Autoblog.com. Retrieved 21 September 2011.</ref> In November 2010 the EPA introduced the first fuel economy ratings in the [[Monroney sticker]]s for [[plug-in electric vehicle]]s.

For the fuel economy label of the Chevy Volt [[plug-in hybrid]] EPA rated the car separately for [[all-electric mode]] expressed in [[miles per gallon gasoline equivalent]] (MPG-e) and for gasoline-only mode expressed in conventional miles per gallon. EPA also estimated an overall combined city/highway gas-electricity fuel economy rating expressed in miles per gallon gasoline equivalent (MPG-e). The label also includes a table showing fuel economy and electricity consumed for five different scenarios: {{convert|30|mi|km}}, {{convert|45|mi|km}}, {{convert|60|mi|km}} and {{convert|75|mi|km}} driven between a full charge, and a never charge scenario. This information was included to make the consumers aware of the variability of the fuel economy outcome depending on miles driven between charges. Also the fuel economy for a gasoline-only scenario (never charge) was included. For electric-only mode the energy consumption estimated in [[kWh]] per {{convert|100|mi|km}} is also shown.<ref name=GCCEPAVolt>{{cite web|url=http://www.greencarcongress.com/2010/11/volt-20101124.html#more|title=Volt receives EPA ratings and label: 93 mpg-e all-electric, 37 mpg gas-only, 60 mpg-e combined|publisher=[[Green Car Congress]]|date=24 November 2010|access-date=24 November 2010}}</ref><ref name=EPAmpge>{{cite web|url=http://www.fueleconomy.gov/feg/phevsbs.shtml|title=2011 Chevrolet Volt|publisher=Fueleconomy.gov|author=[[US Environmental Protection Agency]] and [[US Department of Energy]]|date=4 May 2011|access-date=21 May 2011}}</ref>
[[File:Nissan Leaf EPA fuel economy label.jpg|thumb|2010 [[Monroney label]] showing the EPA's combined city/highway [[miles per gallon gasoline equivalent|fuel economy equivalent]] for an all-[[electric car]], in this case a 2010 [[Nissan Leaf]]]]

For the fuel economy label of the Nissan Leaf [[electric car]] EPA rated the combined fuel economy in terms of [[miles per gallon gasoline equivalent]], with a separate rating for city and highway driving. This fuel economy equivalence is based on the energy consumption estimated in [[kWh]] per 100 miles, and also shown in the Monroney label.<ref name=NYTEPA>{{cite news|url=https://www.nytimes.com/2010/11/23/business/23leaf.html?_r=1&hpw|title=Nissan Says Its Electric Leaf Gets Equivalent of 99 M.P.G.|work=The New York Times|author=Nick Bunkley|date=22 November 2010|access-date=23 November 2010}}</ref>

In May 2011, the [[National Highway Traffic Safety Administration]] (NHTSA) and EPA issued a joint final rule establishing new requirements for a [[fuel economy and environment label]] that is mandatory for all new passenger cars and trucks starting with [[model year]] 2013, and voluntary for 2012 models. The ruling includes new labels for [[alternative fuel]] and [[alternative propulsion]] vehicles available in the US market, such as [[plug-in hybrid]]s, [[electric vehicle]]s, [[flexible-fuel vehicle]]s, [[Fuel cell vehicle|hydrogen fuel cell vehicle]], and [[natural gas vehicle]]s.<ref name=EPA2013>{{cite web|url=http://www.epa.gov/otaq/carlabel/420f11017.htm|title=Fact Sheet: New Fuel Economy and Environment Labels for a New Generation of Vehicles|author=EPA|publisher=[[US Environmental Protection Agency]]|date=May 2011|access-date=25 May 2011}} ''EPA-420-F-11-017''</ref><ref name=GCC2013>{{cite web|url=http://www.greencarcongress.com/2011/05/felabel-20110525.html|title=EPA, DOT unveil the next generation of fuel economy labels|publisher=[[Green Car Congress]]|date=25 May 2011|access-date=25 May 2011}}</ref> The common fuel economy metric adopted to allow the comparison of alternative fuel and advanced technology vehicles with conventional [[internal combustion engine]] vehicles is [[miles per gallon of gasoline equivalent]] (MPGe). A gallon of gasoline equivalent means the number of kilowatt-hours of electricity, cubic feet of [[compressed natural gas]] (CNG), or kilograms of [[hydrogen]] that is equal to the energy in a gallon of gasoline.<ref name=EPA2013/>

The new labels also include for the first time an estimate of how much fuel or electricity it takes to drive {{Convert|100|mi}}, providing US consumers with fuel consumption per distance traveled, the metric commonly used in many other countries. EPA explained that the objective is to avoid the traditional miles per gallon metric that can be potentially misleading when consumers compare fuel economy improvements, and known as the "MPG illusion"<ref>{{cite news|url=http://www.businessweek.com/articles/2014-01-14/not-all-fuel-efficiency-is-equal-understanding-the-miles-per-gallon-illusion|archive-url=https://web.archive.org/web/20140115125904/http://www.businessweek.com/articles/2014-01-14/not-all-fuel-efficiency-is-equal-understanding-the-miles-per-gallon-illusion|url-status=dead|archive-date=15 January 2014|title=Not All Fuel Efficiency Is Equal: Understanding the Miles-Per-Gallon Illusion |newspaper=Bloomberg.com |date=14 January 2014 |access-date=11 November 2014}}</ref> – this illusion arises because the reciprocal (i.e. non-linear) relationship between cost (equivalently, volume of fuel consumed) per unit distance driven and MPG value means that ''differences'' in MPG values are not directly meaningful – only ratios are (in mathematical terms, the reciprocal function does not commute with addition and subtraction; in general, a difference in reciprocal values is not equal to the reciprocal of their difference). It has been claimed that many consumers are unaware of this, and therefore compare MPG values by subtracting them, which can give a misleading picture of relative differences in fuel economy between different pairs of vehicles – for instance, an increase from 10 to 20 MPG corresponds to a 100% improvement in fuel economy, whereas an increase from 50 to 60 MPG is only a 20% improvement, although in both cases the difference is 10 MPG.<ref>{{cite web |url=http://blogs.berkeley.edu/2013/06/03/the-mpg-illusion/ |title=The MPG Illusion |date=3 June 2013 |access-date=11 November 2014}}</ref> The EPA explained that the new gallons-per-100-miles metric provides a more accurate measure of fuel efficiency<ref name=EPA2013/><ref>{{cite news|url=https://www.nytimes.com/2011/05/26/business/energy-environment/26label.html?_r=1&emc=eta1|title=New Mileage Stickers Include Greenhouse Gas Data|author=John M. Broder|work=The New York Times|date=25 May 2011|access-date=26 May 2011}}</ref> – notably, it is equivalent to the normal metric measurement of fuel economy, liters per 100 kilometers (L/100&nbsp;km).

====CAFE standards====
[[File:CAFE mpg curve from NHTSA's Summary of Fuel Economy Performance, December 2014.svg|thumb|200px|Curve of average car mileage for model years between 1978 and 2014]]<!--please fix years in image-->{{Main|Corporate Average Fuel Economy}}
The Corporate Average Fuel Economy (CAFE) regulations in the United States, first enacted by Congress in 1975,<ref>
{{cite web
 |url         = http://www.nhtsa.dot.gov/portal/site/nhtsa/template.MAXIMIZE/menuitem.43ac99aefa80569eea57529cdba046a0/?javax.portlet.tpst=f2d14277f710b755fc08d51090008a0c_ws_MX&javax.portlet.prp_f2d14277f710b755fc08d51090008a0c_viewID=detail_view&javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetoken&itemID=199b8facdcfa4010VgnVCM1000002c567798RCRD&viewType=standard#6
 |title       = CAFE Overview: "What is the origin of CAFE?"
 |publisher   = NHTSA
 |access-date  = 9 July 2008
|url-status     = dead
 |archive-url  = https://web.archive.org/web/20090203174614/http://www.nhtsa.dot.gov/portal/site/nhtsa/template.MAXIMIZE/menuitem.43ac99aefa80569eea57529cdba046a0/?javax.portlet.tpst=f2d14277f710b755fc08d51090008a0c_ws_MX&javax.portlet.prp_f2d14277f710b755fc08d51090008a0c_viewID=detail_view&javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetoken&itemID=199b8facdcfa4010VgnVCM1000002c567798RCRD&viewType=standard#6
 |archive-date = 3 February 2009}}</ref> are federal regulations intended to improve the average fuel economy of cars and light trucks (trucks, vans and [[sport utility vehicle]]s) sold in the US in the wake of the [[1973 oil crisis|1973 Arab Oil Embargo]]. Historically, it is the sales-weighted average fuel economy of a manufacturer's [[Fleet vehicle|fleet]] of current [[model year]] passenger cars or light trucks, manufactured for sale in the United States. Under Truck CAFE standards 2008–2011 this changes to a "footprint" model where larger trucks are allowed to consume more fuel. The standards were limited to vehicles under a certain weight, but those weight classes were expanded in 2011.

====Federal and state regulations====
The [[Clean Air Act (United States)|Clean Air Act]] of 1970 prohibited states from establishing their own air pollution standards. However, the legislation authorized the EPA to grant a waiver to California, allowing the state to set higher standards.<ref name=NYTApril18>{{cite news |title=Calling car pollution standards 'too high,' EPA sets up fight with California |first=Hiroko |last=Tabuchi |author-link=Hiroko Tabuchi |date=2 April 2018 |work=The New York Times |url=https://www.nytimes.com/2018/04/02/climate/trump-auto-emissions-rules.html}}</ref> The law provides a “piggybacking” provision that allows other states to adopt vehicle emission limits that are the same as California's.<ref name=ELQSept03>{{cite journal |last=Giovinazzo |first=Christopher |date=September 2003 |title=California's Global Warming Bill: Will Fuel Economy Preemption Curb California's Air Pollution Leadership |url=https://scholarship.law.berkeley.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1735&context=elq |journal=Ecology Law Quarterly |volume=30 |issue=4 |pages=901–902}}</ref> California's waivers were routinely granted until 2007, when the [[Presidency of George W. Bush|George W. Bush administration]] rejected the state's bid to adopt global warming pollution limits for cars and light trucks.<ref name=NYTDec07>{{cite news |title=EPA Denies California's Emissions Waiver |first=Hiroko |last=Tabuchi |date=19 December 2007 |work=The New York Times |url=https://www.nytimes.com/2007/12/19/washington/20epa-web.html}}</ref> California and 15 other states that were trying to put in place the same emissions standards sued in response.<ref name=WaPoJan08>{{cite news |title=California Sues EPA Over Emissions Rules |first=Keith |last=Richburg |date=3 January 2008 |newspaper=The Washington Post |url=https://www.washingtonpost.com/wp-dyn/content/article/2008/01/02/AR2008010202833.html}}</ref> The case was tied up in court until the [[Presidency of Barack Obama|Obama administration]] reversed the policy in 2009 by granting the waiver.<ref name=GTMJune09>{{cite news |title=EPA grants California emissions waiver |first=Ucilia |last=Wang |date=30 June 2009 |work=Greentech Media |url=https://www.greentechmedia.com/articles/read/epa-grants-california-emissions-waiver}}</ref>

In August 2012, President Obama announced new standards for American-made automobiles of an average of 54.5 miles per gallon by the year 2025.<ref>{{cite web|url=https://obamawhitehouse.archives.gov/the-press-office/2012/08/28/obama-administration-finalizes-historic-545-MPG-fuel-efficiency-standard|title=Obama Administration Finalizes Historic 54.5 MPG Fuel Efficiency Standards|date=28 August 2012|publisher=White House|language=en|access-date=28 November 2019}}</ref><ref>{{Cite news|title=Shifting Gears|last=Fraser|first=Laura|date=Winter 2012–2013|work=NRDC's OnEarth|page=63}}</ref> In April 2018, EPA Administrator [[Scott Pruitt]] announced that the [[Presidency of Donald Trump|Trump administration]] planned to roll back the 2012 federal standards and would also seek to curb California's authority to set its own standards.<ref name=NYTApril18 /> Although the Trump administration was reportedly considering a compromise to allow state and national standards to stay in place,<ref name=NYT2018>{{cite news |title=Quietly, Trump officials and California seek deal on emissions |first=Hiroko |last=Tabuchi |date=5 April 2018 |work=The New York Times |url=https://www.nytimes.com/2018/04/05/climate/trump-california-emissions.html}}</ref> on 21 February 2019 the White House declared that it had abandoned these negotiations.<ref>{{cite news |last1=Phillips |first1=Anna M. |title=Trump administration confirms it has ended fuel-economy talks with California |url=https://www.latimes.com/politics/la-na-pol-california-fuel-economy-trump-20190220-story.html |access-date=11 May 2019 |work=Los Angeles Times |date=21 February 2019}}</ref> A government report subsequently found that, in 2019, new light-duty vehicle fuel economy fell 0.2 miles per gallon (to 24.9 miles per gallon) and pollution increased 3 grams per mile traveled (to 356 grams per mile). A decrease in fuel economy and an increase in pollution had not occurred for the previous five years.<ref>{{cite web|last=Associated Press|date=6 January 2021|title=For first time in 5 years, US gas mileage down, emissions up|url=https://www.ocregister.com/2021/01/06/for-first-time-in-5-years-us-gas-mileage-down-emissions-up|access-date=7 January 2021|website=Orange County Register|language=en-US}}</ref> The Obama-era rule was officially rolled back on 31 March 2020 during the Trump administration,<ref>{{Cite web|url=https://news.yahoo.com/trump-rollback-mileage-standards-guts-151423701.html|title=Trump rollback of mileage standards guts climate change push|website=Yahoo News|date=31 March 2020 |accessdate=2 May 2023}}</ref> but the rollback was reversed on 20 December 2021 during the Biden administration.<ref>{{cite web|last1=Kaufman|first1=Alexander|last2=D'Angelo|first2=Chris|date=20 December 2021|title=EPA Reverses Trump's Fuel Mileage Rules On New Cars|url=https://www.huffpost.com/entry/epa-reverses-trump-fuel-mileage-rules_n_61c0b34de4b061afe395ec7f|access-date=20 December 2021|website=HuffPost|language=en}}</ref>

== Fuel economy of trucks ==
Trucks are usually bought as an investment good. They are meant to earn money. As the Diesel fuel burnt in heavy trucks accounts for around 30%<ref name=":0">{{Cite book |last=Hilgers |first=Michael |url=https://www.worldcat.org/oclc/1237865094 |title=Commercial Vehicle Technology: Fuel consumption and consumption optimization |date=2021 |others=Wilfried Achenbach |isbn=978-3-662-60841-8 |location=Berlin |oclc=1237865094}}</ref> of the total costs for a freight forwarding company there is always a lot of interest in both the haulage industry and the truck builder industry to strive for best fuel economy. For truck buyers the fuel economy measured by standard procedures is only a first guideline. Professional trucking companies measure the fuel economy of their trucks and truck fleets in real usage. Fuel economy of trucks in real usage is determined by four important factors:<ref name=":0" /> The truck technology that is constantly improved by the various OEMs. The driver's driving style contributes a lot to the real fuel economy (different from the test cycles where a standard driving style is used). The maintenance condition of the vehicle influences the fuel efficiency – again different from standardized procedures where the trucks are always presented in flawless condition. Last but not least the usage of the vehicle influences the fuel consumption: Hilly roads and heavy loads will increase the fuel consumption of a vehicle.

== Effect on pollution ==
{{further|Gas-guzzler|Vehicle Efficiency Initiative}}

Fuel efficiency directly affects emissions causing pollution by affecting the amount of fuel used. However, it also depends on the fuel source used to drive the vehicle concerned. Cars for example, can run on a number of fuel types other than gasoline, such as [[Natural gas vehicle|natural gas]], [[Liquefied petroleum gas|LPG]] or [[biofuel]] or electricity which creates various quantities of atmospheric pollution.

A kilogram of carbon, whether contained in petrol, diesel, kerosene, or any other hydrocarbon fuel in a vehicle, leads to approximately 3.6&nbsp;kg of [[CO2|CO<sub>2</sub>]] emissions.<ref name="EPA CO2 est">{{cite web | title = Emission Facts: Average Carbon Dioxide Emissions Resulting from Gasoline and Diesel Fuel | url = http://www.epa.gov/OMS/climate/420f05001.htm | publisher = [[United States Environmental Protection Agency]] | date = February 2005 | work = Office of Transportation and Air Quality | access-date = 2009-07-28 | url-status = live | archive-url = https://web.archive.org/web/20090228190530/http://www.epa.gov/oms/climate/420f05001.htm | archive-date = 2009-02-28 }}</ref>  Due to the carbon content of gasoline, its combustion emits 2.3&nbsp;kg/L (19.4&nbsp;lb/US gal) of [[CO2|CO<sub>2</sub>]]; since diesel fuel is more energy dense per unit volume, diesel emits 2.6&nbsp;kg/L (22.2&nbsp;lb/US gal).<ref name="EPA CO2 est" />  This figure is only the CO<sub>2</sub> emissions of the final fuel product and does not include additional CO<sub>2</sub> emissions created during the drilling, pumping, transportation and refining steps required to produce the fuel. Additional measures to reduce overall emission includes improvements to the efficiency of [[air conditioner]]s, lights and tires.

==Unit conversions==

;US Gallons
* 1&nbsp;mpg ≈ 0.425&nbsp;km/L
* 235.2/mpg ≈ L/100&nbsp;km
* 1&nbsp;mpg ≈ 1.201&nbsp;mpg (imp)

;Imperial gallons
* 1&nbsp;mpg ≈ 0.354&nbsp;km/L
* 282/mpg ≈ L/100&nbsp;km
* 1&nbsp;mpg ≈ 0.833&nbsp;mpg (US)

===Conversion from mpg===
{| style="text-align:right; border:0;"
|-
|
{| class="wikitable" style="float:left; text-align:right;"
|-
! mpg (imp)
! mpg (US)
! km/L
! L/100&nbsp;km
|-
| 5
| 4.2
| 1.8
| 56.5
|-
| 10
| 8.3
| 3.5
| 28.2
|-
| 15
| 12.5
| 5.3
| 18.8
|-
| 20
| 16.7
| 7.1
| 14.1
|-
| 25
| 20.8
| 8.9
| 11.3
|-
| 30
| 25.0
| 10.6
| 9.4
|-
| 35
| 29.1
| 12.4
| 8.1
|-
| 40
| 33.3
| 14.2
| 7.1
|-
| 45
| 37.5
| 15.9
| 6.3
|-
| 50
| 41.6
| 17.7
| 5.6
|-
| 55
| 45.8
| 19.5
| 5.1
|-
| 60
| 50.0
| 21.2
| 4.7
|-
| 65
| 54.1
| 23.0
| 4.3
|-
| 70
| 58.3
| 24.8
| 4.0
|-
| 75
| 62.5
| 26.6
| 3.8
|-
| 80
| 66.6
| 28.3
| 3.5
|-
| 85
| 70.8
| 30.1
| 3.3
|-
| 90
| 74.9
| 31.9
| 3.1
|-
| 95
| 79.1
| 33.6
| 3.0
|-
| 100
| 83.3
| 35.4
| 2.8
|}
|
{| class="wikitable" style="float:right; text-align:right;"
|-
! mpg (US)
! mpg (imp)
! km/L
! L/100&nbsp;km
|-
| 5
| 6.0
| 2.1
| 47.0
|-
| 10
| 12.0
| 4.3
| 23.5
|-
| 15
| 18.0
| 6.4
| 15.7
|-
| 20
| 24.0
| 8.5
| 11.8
|-
| 25
| 30.0
| 10.6
| 9.4
|-
| 30
| 36.0
| 12.8
| 7.8
|-
| 35
| 42.0
| 14.9
| 6.7
|-
| 40
| 48.0
| 17.0
| 5.9
|-
| 45
| 54.0
| 19.1
| 5.2
|-
| 50
| 60.0
| 21.3
| 4.7
|-
| 55
| 66.1
| 23.4
| 4.3
|-
| 60
| 72.1
| 25.5
| 3.9
|-
| 65
| 78.1
| 27.6
| 3.6
|-
| 70
| 84.1
| 29.8
| 3.4
|-
| 75
| 90.1
| 31.9
| 3.1
|-
| 80
| 96.1
| 34.0
| 2.9
|-
| 85
| 102.1
| 36.1
| 2.8
|-
| 90
| 108.1
| 38.3
| 2.6
|-
| 95
| 114.1
| 40.4
| 2.5
|-
| 100
| 120.1
| 42.5
| 2.4
|}
|}

===Conversion from km/L and L/100&nbsp;km===
{| style="text-align:right; border:0;"
|-
|
{| class="wikitable" style="text-align:right;"
|-
! L/100&nbsp;km
! km/L
! mpg (US)
! mpg (imp)
|-
| 1
| 100.0
| 235.2
| 282.5
|-
| 2
| 50.0
| 117.6
| 141.2
|-
| 3
| 33.3
| 78.4
| 94.2
|-
| 4
| 25.0
| 58.8
| 70.6
|-
| 5
| 20.0
| 47.0
| 56.5
|-
| 6
| 16.7
| 39.2
| 47.1
|-
| 7
| 14.3
| 33.6
| 40.4
|-
| 8
| 12.5
| 29.4
| 35.3
|-
| 9
| 11.1
| 26.1
| 31.4
|-
| 10
| 10.0
| 23.5
| 28.2
|-
| 15
| 6.7
| 15.7
| 18.8
|-
| 20
| 5.0
| 11.8
| 14.1
|-
| 25
| 4.0
| 9.4
| 11.3
|-
| 30
| 3.3
| 7.8
| 9.4
|-
| 35
| 2.9
| 6.7
| 8.1
|-
| 40
| 2.5
| 5.9
| 7.1
|-
| 45
| 2.2
| 5.2
| 6.3
|-
| 50
| 2.0
| 4.7
| 5.6
|-
| 55
| 1.8
| 4.3
| 5.1
|-
| 60
| 1.7
| 3.9
| 4.7
|}
|
{| class="wikitable" style="text-align:right;"
|-
! km/L
! L/100&nbsp;km
! mpg (US)
! mpg (imp)
|-
| 5
| 20.0
| 11.8
| 14.1
|-
| 10
| 10.0
| 23.5
| 28.2
|-
| 15
| 6.7
| 35.3
| 42.4
|-
| 20
| 5.0
| 47.0
| 56.5
|-
| 25
| 4.0
| 58.8
| 70.6
|-
| 30
| 3.3
| 70.6
| 84.7
|-
| 35
| 2.9
| 82.3
| 98.9
|-
| 40
| 2.5
| 94.1
| 113.0
|-
| 45
| 2.2
| 105.8
| 127.1
|-
| 50
| 2.0
| 117.6
| 141.2
|-
| 55
| 1.8
| 129.4
| 155.4
|-
| 60
| 1.7
| 141.1
| 169.5
|-
| 65
| 1.5
| 152.9
| 183.6
|-
| 70
| 1.4
| 164.7
| 197.7
|-
| 75
| 1.3
| 176.4
| 211.9
|-
| 80
| 1.3
| 188.2
| 226.0
|-
| 85
| 1.2
| 199.9
| 240.1
|-
| 90
| 1.1
| 211.7
| 254.2
|-
| 95
| 1.1
| 223.5
| 268.4
|-
| 100
| 1.0
| 235.2
| 282.5
|}
|}

==See also==
{{div col|colwidth=28em}}
* [[Automobile costs]]
* [[ACEA agreement]]
* [[Battery electric vehicle]]
* [[Car speed and energy consumption]]
* [[Car tuning]]
* [[Emission standard]]
* [[Energy conservation]]
* [[Energy-efficient driving]]
* [[FF layout]]
* [[Fuel efficiency in transportation]]
* [[Fuel saving devices]]
* [[Gasoline gallon equivalent]]
* [[Motorized quadricycle]] (vehicles with low power engines/low top speed)
* [[Miles per gallon gasoline equivalent]]
* [[Passenger miles per gallon]]
* [[The Very Light Car]]
* [[Vehicle Efficiency Initiative]]
* [[Vehicle metrics]]
* [[Green vehicle]]
* [[Low-carbon economy]]
* [[Low-rolling resistance tires]]
* [[Microcar]]
* [[Plug-in hybrid]]
{{div col end}}

==Annotations==
{{Reflist|group=lower-alpha}}

==References==
{{Reflist|30em}}

==External links==
* [https://www.auto-abc.eu/info/real-fuel-consumption Real fuel consumption by user reports]
* [http://www.fueleconomy.gov/feg/pdfs/guides/FEG2014.pdf Model Year 2014 Fuel Economy Guide ], [[U.S. Environmental Protection Agency]] and [[U.S. Department of Energy]], April 2014.
* [https://ecohungry.com/electric-and-petrol-cars-fuel-efficiency/ Fuel Efficiency in Electric, Hybrid and Petrol Cars – Model Year 2019]

{{Authority control}}

{{DEFAULTSORT:Fuel Economy In Automobiles}}
[[Category:Energy economics]]
[[Category:Fuel technology]]
[[Category:Green vehicles]]
[[Category:Car costs]]