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How the 2008 EPA Fuel Economy Ratings Work


The Results of the 2008 Fuel Economy Ratings
Efficient cars like the Toyota Prius didn't show as big a drop in fuel efficiency ratings as larger automobiles.
Efficient cars like the Toyota Prius didn't show as big a drop in fuel efficiency ratings as larger automobiles.
Justin Sullivan/Getty Images

It's a common complaint drivers have: Their fuel economy doesn't come close to fuel economy that was promised on the car's window sticker. In the past, that was due largely to the fact that the ratings were developed in the 1960s. With the new 2008 fuel economy ratings, drivers should expect to get fuel economy that more closely matches the fuel economy numbers given by the government.

The results can be a bit more confusing than that. Overall, fuel economy numbers have declined because of the new ratings. The 2007 Toyota Camry, for example, got 24 mpg in the city and 33 mpg on the highway, for a combined fuel economy of 27 mpg under the old ratings. With the new ratings, the same car gets an estimated 21 mpg in the city and 30 mpg on the highway, for a combined fuel economy rating of 24 mpg. That change in fuel economy for the same car can be confusing for car shoppers, but it's not the result of any changes to the car. It's because of the changes to the test. Overall, consumers can expect to see city fuel economy ratings for all cars drop about 12 percent, with highway ratings dropping about 8 percent [source: Edmunds.com]. Some cars could show a drop of as much as 30 percent in their city mileage rating and 25 percent in their highway mileage rating [source: Edmunds.com].

While all new cars are now following the new test and have the new ratings, the change can make shopping for a used car more challenging, because it can be tough to tell if the fuel economy rating on the sticker is based on the old or new test. If you're buying used, the best way to check is to visit FuelEconomy.gov, where the government has posted the old and new fuel economy numbers for all mainstream car models, going back to 1985.

­­To learn more about the EPA and fuel economy, look over the links on the next page.­