Here's How To Lose 17 MPG Off Your EPA Rating

Here's How To Lose 17 MPG Off Your EPA Rating

Just the Facts:
  • Ford product development boss says recent issues with vehicles underperforming fuel economy ratings could suggest new scrutiny is needed for the EPA's fuel economy testing.
  • How fast you drive, in what temperatures you drive and the "newness" of your engine all can have a major influence on your observed fuel economy.
  • Ford wants to be "open" with customers regarding why your mileage may vary.

DETROIT — "Your mileage may vary" has become an iconic cultural phrase to explain just about anything that doesn't exactly meet your expectations.

But the root cause — vehicle fuel economy rarely meeting the Environmental Protection Agency-generated figures prominently advertised on the sticker — quickly is losing it whimsy. Car buyers suddenly give a crap about fuel efficiency, and not achieving the "rated" figures isn't a shoulder-shrug joke anymore, as consumers begin to reflect escalating anger at being hoodwinked by new vehicle fuel economy ratings.

Close on the heels of South Korean brands Hyundai and Kia being publicly slapped down because the companies didn't follow EPA testing procedures and 13 of their models' lofty fuel economy figures had to be restated, Ford found itself in a dust-up with consumers regarding its widely boasted ratings of 47 mpg in city, highway and combined economy for its 2013 C-Max and Fusion Hybrid models.

At a media event last week, Raj Nair, Ford's vice president for global product development, attempted to get in front of the issue by saying the recent developments could suggest the EPA once again may need to revisit its fuel economy testing procedures to ascertain if the tests are out of sync with real-world driving. The last time the EPA revised its Federal Test Procedure was for the 2008 model year.

"We want to be open (with the public) about fuel economy," Nair said, adding, "We're working closely with the EPA to determine if test changes are necessary."

Nobody's saying Ford didn't properly conduct its testing — but some C-Max and Fusion Hybrid owners nonetheless have howled about not coming close to the 47-mpg rating and the EPA quickly said it wanted to look into the situation. It could be that hybrids and other electrified vehicles are particularly misrepresented by the current Federal Test Procedure (FTP), which the EPA said is only slightly modified for advanced-powertrain vehicles. The EPA subsequently would not tell The Wall Street Journal if the agency is talking with automakers about revisions to the FTP.

Meantime, Nair spit out some interesting figures to help explain why your real-world fuel economy can really suffer. Most of this you probably already have heard, but Nair quantified with real numbers — although he didn't specifically say to what kind of vehicle the following applies:

  • Drive 75 mph instead of 65 mph: lose 7 mpg.
  • Drive in 40-degree weather instead of 70-degree warmth: lose 5 mpg.
  • A new engine with "break-in" mileage of less than 6,000 miles: lose 5 mpg.
  • If you want to see the parameters for each cycle of the EPA's current fuel economy testing, the agency does a great service by listing them here. We'd have to say a highway schedule that doesn't exceed 60 mph is a problem (some states have 70-mph freeway and interstate speed limits that at least get closer to the 80-mph-plus averages found on many such roads) and even the "high-speed" cycle added with the 2008 revisions to the FTP still averages just 48 mph and spends only about half of the cycle's 9.9 minutes at speeds higher than 60 mph.

    Edmunds says: Like the line from the movie, the public's mad as hell (about ambitiously labeled fuel economy) and isn't going to take it anymore. Automakers advertise the numbers but don't want to be on the hot seat when the gas pump promises don't come to fruition.

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