Well-known motorists club AAA says many cars and trucks it road-tests fall far short of their government fuel-economy ratings.

Using that disappointing fuel economy data from hundreds of road tests in what AAA calls real-world driving, the organization plans to endorse legislation to be introduced Thursday that would require the U.S. Environmental Protection Agency to overhaul its gas-mileage tests.

Environmental groups have argued for years that mileage labels are bogus, but it is significant that AAA is throwing its influence behind the bill to change them.

"There's no doubt that it helps. And it highlights the fact that it's just common sense — providing consumers with accurate information," said David Friedman, a research director for the Union of Concerned Scientists. UCS strongly backs legislation to require realistic mileage ratings.

AAA data come from tests done by drivers across the country "getting groceries, getting stuck in traffic jams, driving the same way you would," said AAA spokesman Mantill Williams.

The organization concedes that its tests aren't scientific but insists the results are representative.

Among vehicles that were farthest off EPA ratings: the 2004 BMW Z4 sports car, which AAA says hit just 14.5 miles per gallon in combined city-highway use, versus a 24 mpg EPA rating; the Chevrolet TrailBlazer SUV, 13.6 mpg in AAA testing versus 17 mpg EPA rating; and the Chrysler PT Cruiser, 17.5 mpg from AAA versus 25 mpg EPA rating.

Fuel-economy numbers posted on new vehicles are generated by 30-year-old EPA tests in which vehicles are run without air conditioning, never exceed 60 mph, never accelerate hard enough to hit 60 mph from a standstill in less than 18 seconds and always go far enough to fully warm up the engine. EPA uses correction factors to try to get closer to actual mileage.

Most highway driving now is faster than 60. Even slow family cars will accelerate to 60 in less than 12 seconds, and many trips are too short to warm the engine.

The so-called Fuel-efficiency Truth-in-Advertising act would require EPA tests to "reflect modern driving patterns and experiences, specifically speed and highway-versus-urban driving," says Rep. Nancy Johnson, R-Conn., co-sponsor of the bill with Rush Holt, D-N.J. "Those are no-brainers," she said.

EPA itself is mulling changes. It is considering how to account for factors that "will lower fuel economy," including, "air conditioning, aggressive driving (e.g. high speeds and quick accelerations), cold weather, traffic congestion and others."

In a statement, EPA promises to "propose appropriate changes this year."

— Reported by James R. Healey, USA Today;





-Matt-