EPA's mileage estimates to get real-world overhaul


January 11, 2006

DETROIT – The Environmental Protection Agency yesterday proposed the first major overhaul in 20 years in the way it calculates fuel economy ratings for cars and trucks.

The overhaul would reduce mileage estimates by 5 percent to 30 percent, depending on the type of driving and kind of vehicle, the EPA said.

The new testing method would come much closer to bridging "the gap between what the window sticker says and what consumers can expect in their fuel economy," said Stephen L. Johnson, EPA's administrator.

The EPA expects to introduce the changes starting with 2008 models, which will go on sale as early as a year from now.

Consumer groups have long complained that the EPA's ratings are far too optimistic, compared with fuel economy that drivers achieve under real-world conditions. Recent tests by Consumer Reports magazine, for example, found that EPA window stickers could be off by up to 50 percent.

The new EPA calculations will have the greatest impact on hybrid-electric vehicles, the agency said, cutting estimated fuel economy sharply on some of the industry's most sought-after models now that gasoline prices have soared.

For all vehicles, the EPA said its new testing methods would result in a 10 percent to 20 percent drop in fuel economy estimates in city driving, and a 5 percent to 15 percent decline in highway performance.

But for hybrids, which run off both a gasoline engine and an electric battery, city driving estimates could drop by 20 percent to 30 percent. The decline in their highway ratings would be 5 percent to 15 percent, the same as for regular cars.

Buyers are willingly paying thousands of dollars above the price of conventional vehicles, and waiting up to a year in the case of Toyota's most popular hybrid, the Prius, all in the belief that they yield much better gas mileage.

While hybrids are almost always more fuel efficient than conventional vehicles, EPA officials said their estimates for city driving would shrink more because their engines are more sensitive to changes in road conditions, as well as the use of fuel-draining features, such as air conditioning systems and electronic controls.

The EPA could not give estimates for any other specific vehicles. And at this point, they would not be completely accurate. Automakers have some time to improve their fuel economy ratings under the new calculations.

Johnson, the EPA administrator, said the proposed standards, which will be open to public comment for 60 days, are meant to more accurately depict what consumers can expect from new cars and trucks.

In its report in October, Consumer Reports said it found shortfalls in as many as 90 percent of the 203 vehicles it tested, which were built between the 2000 and 2006 model years.

The most inaccurate results came in city driving, especially involving hybrid cars.

But popular models like the Chrysler 300C sedan also had inaccurate estimates: The magazine calculated its fuel economy in city driving at 10 miles per gallon, versus the 17 mpg estimate on its window sticker, a difference of 41 percent.

Likewise, the EPA measured the city driving performance of the Honda Odyssey minivan at 20 mpg, but the magazine said it only achieved 12 mpg, a 40 percent discrepancy.

The agency's new testing method, however, will have no effect on the regulations used in judging whether auto companies are meeting their fuel economy standards, which are overseen by the Transportation Department.

The new government estimates, like those used by the consumer magazine in its testing, will include much more information to make the calculations.

For example, the EPA now will use data from tests meant to show how vehicles perform under conditions known to deplete gasoline. They include driving at high speeds and with rapid acceleration, as well as performance when air conditioning is in use and driving in cold temperatures.

The EPA also said it planned to consider other conditions that can hurt fuel economy, including road grade, wind velocity, whether tires are properly inflated, and the type of fuel in a vehicle's gas tank.

Johnson, the EPA administrator, emphasized that fuel economy estimates do not reflect anything that auto companies – or consumers – have done wrong when it comes to gasoline mileage.

"What this proposal does is give consumers better information," Johnson said yesterday on a conference call with reporters. He went on, "There is no perfect test" and consumers' performance would vary, even once the new calculations take effect.

Detroit's two biggest auto companies, General Motors and Ford Motor, said they were in favor of more accurate information but did not say whether they would embrace the new calculations.

"GM supports providing consumers with more accurate fuel economy data for comparative purposes, and we appreciate the opportunity to provide comments on this rulemaking," the company said in a statement.

Ford, in its statement, said it backed changes "that will help provide consumers with more meaningful information for their purchasing decisions." Other companies did not comment.

Environmental groups said the move was a much-needed first step to make the standards reflect drivers' experience. But it did little to deal with the fundamental issue of improving fuel economy itself, they said.

"The current fuel economy labeling system is broken," Don MacKenzie, an engineer with the Union of Concerned Scientists, said in a statement. "EPA's proposal is a long overdue tune-up that better reflects the growing diversity of vehicle technologies and today's driving conditions."