This is an excerpt from EERE Network News, a weekly electronic newsletter.

January 18, 2006

EPA Proposes Lower, More Realistic Fuel Economy Estimates

The U.S. Environmental Protection Agency (EPA) proposed on January 10th to provide consumers with more realistic fuel economy information when shopping for cars, sport utility vehicles, and pick-up trucks. The EPA's proposed new fuel economy estimates will include vehicle-specific data from tests designed to replicate three factors that can greatly affect fuel economy: use of air conditioning, cold temperature operation, and operation at high speed or with rapid acceleration. The EPA is also proposing an across-the-board adjustment to better account for other conditions that can affect fuel economy but that aren't included in the tests, such as road grade, wind, tire pressure, load, and the effects of different fuel properties. According to a study released by the American Automobile Association (AAA), the new test methods will better reflect how people actually drive. However, even with the improved estimates, the EPA notes that actual fuel economy will vary, since no test can ever account for all individual driving styles, vehicle maintenance practices, and road conditions. See the AAA press release.

Under the new methods, the city mileage estimates for most vehicles would drop 10 to 20 percent from today's labels, depending on the vehicle, while highway mileage estimates would generally drop 5 to 15 percent. The new methods will take effect for model year 2008 vehicles, which will generally be available for sale in fall of 2007. The proposed regulations will not affect the Corporate Average Fuel Economy (CAFE) program that sets fuel economy standards for automakers, since the CAFE program uses its own set of test methods and procedures to determine fuel economy. See the EPA press release and read the proposed regulations on the EPA Fuel Economy Regulations Web page.