Fuel economy tests: Outmoded mileage tests badly shortchange consumers

2013-09-16T00:00:00Z Fuel economy tests: Outmoded mileage tests badly shortchange consumersBy William H. Noack Arizona Daily Star
September 16, 2013 12:00 am  • 

Of all the rules set forth by the federal government to regulate the U.S. auto industry — and there are thousands — none is more frustrating to consumers and car companies alike than the EPA’s requirement that fuel economy be posted on new-car stickers.

Very few consumers actually achieve the fuel economy posted on their sticker. The EPA itself has admitted that real-world fuel economy is usually about 20 percent lower than its own lab numbers.

Part of this is because of the quirky provisions of the testing procedures, and part is because a whole new generation of clean diesels, hybrids and electrics has rendered the testing protocol outdated, if not obsolete.

Bottom line: the EPA should either scrap the rule altogether or — at a minimum — repair it so it’s more in keeping with the fuel economy achieved by real people driving on real roads.

The test procedures, themselves, are cumbersome. Since there are more than 250 car and truck nameplates available for sale in the United States, the EPA tests only about 15 percent of them in their labs. The automakers are allowed to test the others themselves and submit fuel economy data to the EPA for review.

To save costs, automakers are able to submit a single fuel economy number for all their vehicles with the same weight, engine and transmission, even if the outer sheet metal of the vehicles may be different.

The lab tests are done by placing vehicles on a mechanical treadmill called a dynamometer. Thus, the testing doesn’t take into consideration factors like individual driving styles, temperature or geography.

The test cycling of the dynamometers is also a bone of contention. Since the EPA test cycling favors city driving, many owners of hybrids say their real-world fuel economy is far less than the EPA numbers.

There have been class-action lawsuits over the discrepancies and even a “restating” of hybrid fuel economy by a major automaker.

Ironically, diesel owners point out that their vehicles — which generally are more efficient in highway driving — frequently do better than the EPA posted number.

Another factor that distorts the EPA numbers from real-world fuel economy is the fuel the agency uses in testing. It contains no ethanol.

Gasoline that we purchase today at gas stations across the country contains as much as 10 percent ethanol — which the EPA says can lower fuel economy by about 4 percent. It would seem logical that the EPA should use gasoline in its testing with the same ethanol content as that purchased by motorists when they fill up their tanks.

The fact that so many consumers are not getting the advertised fuel economy is a sign that something’s clearly out of whack.

 The EPA has a responsibility to get the numbers right.

William Noack is a retired General Motors executive.

Copyright 2014 Arizona Daily Star. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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