One-In-Three Americans Doubt Fuel Economy Ratings

AAA Analysis Reveals Gentle Driving Style Helps


A new AAA survey reveals that one-in-three Americans do not believe the U.S. Environmental Protection Agency’s (EPA) new vehicle window sticker accurately reflects the fuel economy they achieve when driving. To assess the accuracy of this perception, AAA in partnership with the Automobile Club of Southern California’s Automotive Research Center (ARC), tested the vehicles independently to verify the fuel economy. 


AAA and the ARC 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 that drivers question whether the fuel economy rating for their vehicle is accurate,” said John Nielsen, AAA’s managing director, Automotive Engineering and Repair. “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 conducted a comprehensive analysis of 37,000 EPA records, representing more than 8,400 vehicle make, model and year combinations, to identify trends in real-world fuel economy.  Surprisingly, among the self-reported data, eight out of 10 drivers reported fuel economy that was higher than the combined city and highway EPA mileage rating for their vehicle. 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 higher 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 that submit their vehicle’s fuel economy to the EPA report mileage that beats the window sticker rating,” continued Nielsen. “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 conducting this analysis, AAA engineers identified a list of vehicles that were frequently reported as failing to achieve the EPA’s mileage rating. The majority of these vehicles, including the scrutinized Hyundai and Kia models, have since been retested and, in some cases, mileage ratings were revised by the manufacturer.  AAA selected three additional vehicles – a 2014 full-size pickup truck, a 2014 large sedan and a 2012 medium sedan – for further testing.


The Auto Club’s ARC measured the fuel economy of the vehicles independently over the course of several weeks, both on a chassis dynamometer and on Southern California streets.  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.


“In addition to logging hundreds of miles in various driving environments, the research team put the vehicles through EPA-specified testing designed to mimic the real-world conditions, including city, highway and aggressive driving,” said Megan McKernan, manager of the Auto Club’s ARC. “The findings indicate that while vehicles tested are capable of achieving the EPA rating, a driver’s real-world mileage will vary based on driving style.”


McKernan said that Southern California drivers should try to:


  • Optimize daily driving.  Maintain steady speeds. A car uses extra fuel when it accelerates.  Cruise control may be a fuel saving option for motorists who drive a lot because a steady speed conserves fuel.  This is helpful when driving on level roads.  However, cruise control can actually hurt your mileage if you drive on hilly terrain. 


  • Minimize last-minute braking. Anticipate traffic conditions. Be alert for slow-downs and red lights and coast up to them, if possible. Drive smoothly, avoiding “jackrabbit starts.” The faster you drive, the more fuel used. Remember, however, that traveling slower than traffic flow can cause a safety hazard.


  • Make sure you’re shopping around.  Looking for low gasoline prices in their local communities may save motorists money, according to McKernan. But traveling long distances to save a few cents wastes fuel and may cost motorists more money.


  • For families that have more than one vehicle, select the most fuel-efficient vehicle that meets the task at hand. Don’t automatically jump into the SUV or truck when the sedan will do. Consider renting a fuel-efficient vehicle for vacations and long trips to save on fuel costs. Conversely, consider renting a full size truck instead of buying it if you only need its capabilities occasionally.


  • Consolidate trips and errands to cut down on driving and number of miles driven. Plan your route and look for a location where you can take care of all or most errands. Avoid excessive idling.  Parking your vehicle and walking into the store or restaurant instead of using a drive through will save gas and the walking may improve your health. Choose a shopping center where you can park and walk to most of the stores you need.


In the next phase of AAA’s fuel economy testing series, to be released in late 2015, researchers will measure the impact that specific driving behaviors, such as acceleration rates and idle time, have on an individual driver’s fuel economy.