2008 models have lower gas mileage estimates

Gas pump handle

For the first time since the mid-'80s, the Environmental Protection Agency has revised the test it uses to measure city and highway fuel consumption.

The goal is to provide a more accurate estimate of what you'll get in real-life driving.

That means new cars and trucks are being tested at higher speeds, with harder acceleration and the air conditioning on for part of the time.

As a result, 2008 gas mileage estimates are down 10% to 25% from comparable 2007 models.

The largest declines are for cars with four-cylinder engines and hybrid powertrains, which must worker harder than larger engines when the air conditioner is on and when you really punch the accelerator.

The new test reduced the city mileage for a typical compact by 4 miles per gallon and by 10 m.p.g. for some hybrids.

Models with V6 and V8 engines only lost 1 or 2 m.p.g.