The EPA announced that it would be overhauling its methodology for determining fuel economy ratings for vehicles in the 2008 model year (late 2007 calendar year). Expected to be hit most? Hybrid city fuel economy estimates, which could drop 20-30%.
Link: SF Chronicle
For all vehicles, the EPA said its new testing methods would result in a 10 to 20 percent drop in fuel economy estimates in city driving, and a 5 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 to 30 percent. The decline in their highway ratings would be 5 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.
Although 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.
I believe that this is a good thing. EPA economy listed should reflect "real-world" conditions, such as playing the radio, or driving your car in the heat or cold. The kicker though, buried in the bottom of this article:
The new, lower ratings, however, will not be used to gauge compliance with government regulations requiring automakers to produce fleets averaging at least 27.5 mpg for cars and 21 mpg for light trucks.
Shorter federal government: Although we know the values do not reflect real-world driving conditions, that is the way we've always done it, so we will continue to use the misleading numbers to calculate fleet average.