How Vehicles Are Tested

How Vehicles Are Tested

Fuel economy is measured under controlled conditions in a laboratory using a standardized test procedure 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 10-15 percent of them through their own tests at the National Vehicles and Fuel Emissions Laboratory.
Estimating MPG with Laboratory Tests

The energy required to move the rollers can be adjusted to account for wind resistance and the vehicle's weight.