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Fuel Economy

Data & Testing

The test data used to determine fuel economy estimates is derived from vehicle testing done at EPA's National Vehicle and Fuel Emissions Laboratory in Ann Arbor, Michigan, and by vehicle manufacturers who submit their own test data to EPA.

Each year, EPA provides fuel economy data to the Department of Energy (DOE), the Department of Transportation (DOT) and the Internal Revenue Service (IRS) so that they can administer their fuel economy-related programs.

  • DOE publishes fuel economy label values in the annual Fuel Economy Guide and on http://www.fueleconomy.gov.
  • DOT receives the manufacturers' fleet average fuel economy from EPA, and determines if manufacturers are complying with the federal corporate average fuel economy (CAFE) standards.
  • EPA provides IRS with the fuel economy data for vehicles which may be subject to the Gas Guzzler tax penalty. IRS is responsible for collecting those taxes from manufacturers.

EPA requires auto manufacturers to change or update their MPG (miles per gallon) values on fuel economy labels (window stickers) if information comes to light that show that the values are too high. See updates to fuel economy labels

Testing advanced technology and alternative fuel vehicles

Fuel economy information is required for all vehicles to determine appropriate values for fuel economy labels and for the CAFE program. The regulations clearly specify, for example, that both City and Highway test values are required for labeling and CAFE. The regulations also require that label test results must be adjusted using specified methods in order to reflect real-world fuel economy. While EPA strives to periodically update the regulatory test procedures such that all technologies are appropriately addressed, there may be instances when some emerging technologies or fuels are not able to be tested using existing regulations. Because of this, EPA has special regulatory provisions that allow EPA to direct manufacturers to test such vehicles using methods specified by EPA. Similarly, EPA is able to determine the content and appearance of the fuel economy labels when existing regulations do not appropriately address the technology or the fuel being used. For example, the regulations do not currently address how to determine City and Highway fuel efficiency values for electric vehicles. During the period when regulations are being developed for electric vehicles, EPA has specified, for example, that manufacturers use an accepted procedure developed by the Society of Automotive Engineers: the procedure known as SAE J1634. Further, to better approximate expected real-world performance, EPA has directed that the manufacturers adjust the test results (including City and Highway fuel efficiency and driving range) for the fuel economy label using equations and methods specified in the regulations.

The following fuel economy reports and data are available online:

  • Fuel Economy Guide Data: These files include the fuel economy label values for each model type. Downloadable, delimited text files for import into databases or spreadsheets -- by model year

  • Fuel Economy Guide 
    Download the latest Fuel Economy Guide
    Copies of Fuel Economy Guide booklets are available from:
    NREL Fuel Economy Guide Request
    1617 Cole Blvd, MS1633
    Golden, CO  80401

  • Fuel Economy Test Car List Reports: These files include the original test data used to determine the label values. This link covers the data from model years 1978-1997. Downloadable, detailed descriptions of vehicle fuel economy tests -- by model year

  • Fuel Economy Test Car List Data: These files include the original test data used to determine the label values. This link covers the from model years 1986 to present. Downloadable, delimited vehicle description data for import into databases/spreadsheets -- by model year

Related Information

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