AAA finds 8 in 10 drivers report their mpg tops EPA ratings

Eight in 10 drivers report getting better fuel economy than the EPA ratings posted on their vehicles’ window stickers, AAA says in a new study.

After an earlier AAA survey indicated that one-third of Americans doubt the accuracy of the EPA’s window stickers, the association did its own analysis and testing.

AAA’s conclusion: Driver behavior and environmental conditions are more likely responsible than vehicle shortcomings for real-world fuel economy variations from the EPA ratings.

AAA said it analyzed 37,000 records reported by drivers to the EPA’s fueleconomy.gov website representing more than 8,400 vehicle make, model and year combinations. It found that eight in 10 drivers reported that their fuel economy was higher than the combined city/highway EPA ratings for their vehicles.

“For years, we’ve heard that drivers question whether the fuel economy rating for their vehicle is accurate,” John Nielsen, AAA’s managing director for automotive engineering and repair, said in a statement. “In the interest of our members, AAA aimed to address this issue with a multi-phase testing series designed to uncover the real reasons behind fuel economy variations.”

AAA engineers who examined the records found that:

• Vehicles with manual transmissions achieved fuel economy 17 percent higher than the EPA rating.
• Drivers of diesel-powered vehicles reported fuel economy 20 percent higher than the EPA’s calculations.
• Drivers of pickups with turbocharged V-6 engines -- the Ford F-150 is the only one of this kind -- reported fuel economy 9 percent lower than the window sticker, while drivers of gasoline-powered pickups with V-8 engines reported 5 percent higher fuel economy than the window label.
• Turbocharged four-cylinder sedan owners said their cars’ fuel economy came in 4 percent lower than the window sticker, but drivers of sedans with nonturbo V-6 engines claimed they beat the window label by 9 percent.

AAA engineers also tested three vehicles -- a 2014 full-size pickup, a 2014 large sedan and a 2012 medium sedan -- and confirmed that the EPA’s ratings were accurate.

“Over the course of several weeks, testing was conducted using a certified dynamometer and on the streets of Southern California,” AAA said in the statement. “Test results from of all three vehicles confirmed the EPA mileage rating was accurate, leaving AAA to conclude that driving behaviors, vehicle condition, driving environment and terrain are likely responsible for most deviations from EPA ratings that consumers experience.”

AAA researchers this year plan to test the effects that specific behaviors such as acceleration rates and idle time have on fuel economy.

In February, the EPA clarified its testing procedures to deliver more precise window label numbers.

Ford, Hyundai, Kia and Mercedes-Benz have had to restate the fuel economy ratings of numerous models since 2012.