Fuel economy: Real-world mpg vs. the EPA’s window sticker

Updated Jun 12, 2019

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AAA 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.

AAA testing indicates vehicles operate most efficiently between 30 and 50 mph.AAA testing indicates vehicles operate most efficiently between 30 and 50 mph.

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 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:

  • 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 to 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.

The test was conducted in Southern California over the course of several weeks, using a certified dynamometer. AAA reported test results from of all three vehicles confirmed the EPA mileage rating was accurate, and they concluded factors such as driving behaviors, vehicle condition, driving environment and terrain are likely responsible for most deviations from EPA ratings.

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.

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