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US light-duty vehicles 1975–2006

Kimmo Klemola

The figures below are the result of various data sets and own life-cycle calculations. Especially valuable data set was the EPA study for US vehicles [Heavenrich, 3]. Comments for figures are given after each diagram.

Curb weight has great effect on fuel consumption and carbon dioxide emissions of a vehicle. In USA, the inertia mass of a car is moved in average 300 000 km between manufacturing and scrapping of a vehicle.


Fuel consumption is affected by many factors. Compared to Europe, in USA, the cars are heavier, with greater horsepower, there are more 4WD and automatic transmission cars and the share of less aerodynamic SUVs, pickups and vans is higher. All these deteriorate the fuel economy.



Tank-to-wheel emissions come from the exhaust pipe of the car.



Well-to-wheel emissions take into account the emissions in the fuel manufacturing and transporting. The emissions of manufacturing, infrastructure, scrapping, recycle and maintenance are not negligible. Total life-cycle takes into account all emissions of the car.



The fuel economy and carbon dioxide emissions of new US light-duty vehicles have become worse and worse for 20 years. Consequently, replacing a 20 year old car with a new car does not make things better.



Increasing fraction of vehicles equipped with 4WD and automatic transmission has negative effect on fuel economy. 



Diesel and hybrid vehicles are much more efficient than gasoline vehicles. Only 1.5% of the light-duty vehicles sold in USA in 2006 were either diesel or hybrid vehicles. In some European countries, the diesel fraction of new vehicles is 70%. If >8500 lb GVWR vehicles, which are used like light-duty vehicles, are taken into account, the diesel share of US light-duty vehicle fleet would be about 2%.



Bigger engines, more fuel burned. In USA, about one million huge >8500 lb GVWR vehicles (SUVs and pickup trucks) are sold. If these are taken into account, the engine displacement would be considerably greater.



More horsepower, more fuel burned.



With a population 90 million less than in Europe, Americans buy more cars.



Americans buy more and more pickup trucks, SUVs and vans.

Some emissions of a car are high in manufacturing stage:



  1. Maclean Heather L., Lester B. Lave, A life-cycle model of an automobile, Environmental Policy Analysis, Vol. 3, No. 4, 1998.

  2. Christidis Panayotis, Hidalgo Ignacio, Soria Antonio, Dynamics of the introduction of new passenger car technologies, The IPTS Transport technologies model, Report EUR 20762 EN, June, 2003.

  3. Heavenrich Robert M., Light-duty automotive technology and fuel economy trends: 1975 through 2005, Advanced Technology Division, Office of Transportation and Air Quality, U.S. Environmental Protection Agency, July, 2005.

  4., 2005.

  5. Kågeson Per, Reducing CO2 emissions from new cars, European Federation for Transport and Environment, 2005.

  6. Sullivan J.L., Williams R.L., Yester S., Cobas-Flores E., Chubbs S.T., Hentges S.G., Pomper S.D., Life cycle inventory of a generic US family sedan overview of results USCAR AMP project, Society of Automotive Engineers, report 982160, 1998.

  7. MacLean Heather L., Lave Lester B., Evaluating automobile fuel/propulsion system technologies, Progress in Energy and Combustion Science, 2000.

  8. Effectiveness and impact of Corporate Average Fuel Economy (CAFE) standards, Committee on the Effectiveness and Impact of Corporate Average Fuel Economy (CAFE) Standards, Board on Energy and Environmental Systems Division on Engineering and Physical Sciences, Transportation Research Board, National Research Council, 2002.

  9. Monitoring of ACEA’s commitment on CO2 emission reduction from passenger cars (2001) final report, Joint Report of the European Automobile Manufacturers Association and the Commission Services, June 25, 2002.

  10. New registrations in Europe by country 2004, European Automobile Manufacturers Association,, Statistics, 2005.

  11. International energy annual 2003, Energy Information Administration, MayJuly, 2005.

  12. Eurostat, November 14, 2005.

  13. Forest resources assessment 2000, Department of Forestry, Food and Agriculture Organization of the United Nations (FAO), Rome, Italy, 2003.

  14. The Nordic Council of Ministers, Rapid replacement of passenger cars a pathway to sustainable mobility, January, 2003.



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