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How Vehicles Are Tested

Fuel economy is measured under controlled conditions in a laboratory using a series of tests specified by federal law. Manufacturers test their own vehicles—usually pre-production prototypes—and report the results to EPA. EPA reviews the results and confirms about 15%–20% of them through their own tests at the National Vehicles and Fuel Emissions Laboratory.

Estimating MPG with Laboratory Tests

This website is administered by Oak Ridge National Laboratory for the U.S. DOE and the U.S. EPA.