With sky-high oil prices, the government is again considering forcing auto makers to improve gas mileage — a move that could have deadly consequences.

According to a published report by the Insurance Institute for Highway Safety, since such regulations were first introduced in the 1970s, every mile gained in fuel efficiency has resulted in 7,000 lives lost. Their research indicates that 46,000 people who were killed in small car crashes would have survived in larger vehicles.

"Small cars, cars weighing less than 2,000 pounds, which are typically very fuel efficient, have twice the mortality rates of those weighing 3,000," Brian O'Neill of the Insurance Institute for Highway Safety said.

Current law says passenger cars have to get 27.5 miles per gallon, and that light trucks need to get just under 21 miles per gallon. If automakers don't meet that standard, they face stiff penalties. Mercedes Benz paid $20 million in fines last year. Volvo paid $11 million. And they make some of the safest cars on the road.

"If I were buying a car for my teenage daughter, I would probably buy her a larger, heavier car," Steve Plotkin of Argonne National Labs, a research center operated by the University of Chicago and the Energy Department, said.

On average, cars today are 1,000 pounds lighter than they were 20 years ago. But some say the answer is better engines, not smaller cars.

"The industry can improve the fuel efficiency substantially without changing the size or changing the safety characteristics of automobiles," Plotkin said.

Environmentalists like Tim Carmichael of the Coalition for Cleaner Air disagree, saying all cars need to be smaller and more efficient, that oversized vehicles like SUVs are the real threat.

"They are more safe for the people in the vehicle, but they make the roads more dangerous for everyone else that's on the road," he said.