Real-World MPG vs EPA Window Sticker

Fuel Filler BWS_3181_01AAA report shows 80-percent of new vehicle owners getting better MPG than expected; EPA making more testing changes

About a third of the new trucks we’ve tested during the past couple years have delivered better real-world highway fuel numbers than the EPA window stickers showed.

According to a fact sheet just released by AAA, we aren’t the only ones who see 5- to 10-percent better fuel economy than the EPA test labs report. In fact, the study says 8 in 10 (81.8 percent) of motorists that self-reported to the EPA website claimed their vehicles that had better-than-EPA MPG.

Those reports covered more than 8,400 vehicle make, model and year combinations.

“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 testing indicates vehicles operate most efficiently when between 30-50mph. Every 5mph above 50mph is like paying 19 cents per gallon for gas.AAA testing indicates vehicles operate most efficiently when between 30-50mph. Every 5mph above 50mph is like paying 19 cents per gallon for gas.

AAA engineers who examined the records found that:

  • Drivers report a real-world fuel economy that averages 12 percent higher than the combined city/hwy EPA miles ratings for their vehicle.
  • 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-6s (Ford F-150 EcoBoost) 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.

AAA engineers also selected three vehicles — a 2014 full-size pickup, a 2014 large sedan and a 2012 medium sedan — whose owners reported mpg 9-12 percent lower than the EPA sticker.

These vehicles were subjected to a month of chassis dyno, and road tests with the driver’s keeping detailed logs of traffic, weather and fuel consumption.

“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.