Study changes fuel economy ratings

A new AAA survey reveals that eight out of 10 drivers report getting better fuel economy than the combined city and highway EPA mileage ratings for their vehicle.

AAA engineers conducted a comprehensive analysis of 37,000 records submitted to the U.S. Environmental Protection Agency (EPA), representing more than 8,400 vehicle make, model and year combinations, to identify trends in real-world fuel economy. Additional findings include:

  • Owners of vehicles equipped with manual transmissions reported 17 percent higher fuel economy than EPA ratings.
  • Owners of diesel-fuel vehicles, including light trucks, reported 20 percent better fuel economy than EPA ratings.
  • Truck owners with gasoline-fuel V-8 engines reported fuel economy five percent higher than EPA ratings, while owners of turbocharged V-6 engines reported fuel economy that was nine percent lower.
  • Owners of sedans with V-6 engines reported a nine percent higher fuel economy than EPA ratings, while owners of turbocharged four cylinder engines reported fuel economy that was four percent lower.
  • Minivan owners reported real-world fuel economy that was equal to or slightly lower than EPA ratings.

“The vast majority of drivers who submit their vehicle’s fuel economy to the EPA report mileage that beats the window sticker rating,” said John Nielsen, AAA’s managing director of Automotive Engineering and Repair. “Although self-reported data has limitations, it’s encouraging to see real-world fuel economy that more closely aligns with, or even exceeds, automaker promises.”

In addition, the survey showed that one-in-three Americans do not believe the EPA’s new vehicle window sticker accurately reflects the fuel economy they achieve when driving. To assess the accuracy of this perception, AAA performed an analysis of data collected on the EPA’s website, along with laboratory and real-world vehicle testing, and found that driver behaviors and environmental conditions, rather than vehicle shortcomings, are likely responsible for most fuel economy variances.

“For years, we’ve heard drivers questioning whether the fuel economy ratings for their vehicles are accurate,” said Nielsen. “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.”

In the next phase of AAA’s fuel economy testing series, to be released in late 2015, researchers will measure the impact driving behaviors, such as acceleration rates and idle time, have on an individual driver’s fuel economy. In the meantime, AAA recommends drivers take a closer look at their driving habits to understand the role they play in the fuel efficiency of their vehicle.