Information on Car Fuel Mileage and Technologies to Improve It

filling-a-car Car fuel mileage refers to the distance in miles a car can drive on 1 gallon of fuel. The unit of measurement is mpg (miles per gallon). First some important information. When browsing around the internet comparing car fuel mileage figures you need to know which gallon is being referred to - the U.S. or imperial gallon - since the imperial gallon is approximately 20% larger than the U.S. gallon. In addition fuel efficiency testing is conducted differently in different countries leading to varying mpg statistics. You should always try to compare figures from the same country.

A higher mpg means better fuel economy - you can travel further for the same amount of fuel.

The two extremes of car fuel mileage are a top fuel dragster which consumes about 24 U.S. gallons per mile (or 0.042 mpg) and the world record holding Pac Car which manages 12,660 mpg. Most people in standard production cars achieve a fuel efficiency somewhere between 15 and 40 mpg. Governments want to raise this figure. New cars sold today in the U.S. must meet a fuel economy standard of 27 mpg however this will slowly be increased to 35.5 mpg by 2016. The European Union went even further, demanding a car fuel mileage of 47 mpg from 2012.

The biggest factor affecting fuel mileage is choice of car, although driving style also plays a very important role. The fuel efficiency of both petrol and diesel engines has improved markedly in recent decades (some diesel engines are now up to 45% efficient), as manufacturers have devoted a lot of time to research new technologies. The main ways manufacturers have improved car fuel mileage are:

  • Designing the exterior of the vehicle to reduce aerodynamic drag
  • Reducing vehicle weight
  • Lowering rolling resistance of tyres
  • Using lower friction engine oils
  • Engines with variable valve timing
  • Fuel injected petrol engines
  • Turbocharged fuel injected diesel engines
  • Common Rail diesel engines
  • Combining a downsized engine with an electric drive system and battery (hybrid electric)
  • Automatically shutting off the engine when the car is not moving (stop start)
  • Recapturing wasted energy while braking (regenerative braking)


    • The best vehicles for car fuel mileage return average figures in excess of 50 mpg. Most are small cars such as the Fiat 500, Smart for Two and Citroen C3, but there are some larger cars returning similar figures, most notably the Toyota Prius hybrid, which is the most successful hybrid car worldwide to date.

    An average U.K. household spends £3000 a year on fuel. By changing to a vehicle with better mileage the savings that can be made and the benefits to the environment are considerable.

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