How are vehicles tested for fuel economy?

The fuel economy estimates are the average of test results conducted for the U.S. EPA. Professional drivers in controlled laboratory conditions drive the vehicles. The results are adjusted to account for differences between the controlled laboratory conditions and real-world driving. Using these procedures ensures that all testing is fair so that you may compare the results of different vehicles with confidence.

No test can simulate all possible combinations of conditions: climate, driver behavior, and car care habits. Actual fuel economy depends on how, when and where a vehicle is driven. EPA has found that the fuel economy obtained by most drivers will be within a few miles per gallon (mpg) of the estimates in the fuel economy guide.