The test simulates a 10-mile trip and averages 48 mph. To make the numbers in the Fuel Economy Guide more useful for consumers, EPA adjusts these laboratory test results to account for the difference between controlled laboratory conditions and actual driving on the road. The laboratory fuel economy results are adjusted downward to arrive at the estimates in this booklet and on the labels seen on new cars, light trucks, and vans. Experience has proven that these adjustments make the mileage estimates in this Guide correspond more closely to the actual fuel economy realized by the average driver. No test can simulate all possible combinations of conditions, climate, driver behavior, and car care habits.
Actual mileage depends on how, when, and where the vehicle is driven.
EPA has found that the mpg obtained by most drivers will be within a few mpg of the estimates in this booklet. To find out what you can do to improve the fuel economy of your car look at Driving More Efficiently and Keeping Your Car in Shape . The size class for cars is determined by measuring the interior volume as described below. The size class for trucks is defined by the gross vehicle weight. Fuel economy regulations do not apply to heavy-duty vehicles.