Installing air bags for drivers and front-seat passengers would add $200 to the price of a new car, but the thousands of lives it would save each year are worth it, say lawmakers who want to mandate it.

A group of senators introduced legislation Thursday to make air bags standard equipment in all new cars by late 1995 and in all light trucks and vans by late 1997. They estimated it would prevent 12,000 deaths annually."The single most important vehicle improvement we can make to save lives and prevent injuries is to require air bags in all cars and light trucks," said Sen. John Danforth, R-Mo. Consumer groups and several insurance companies endorsed the bill.

"Air bags save lives, it's as simple as that," said Judith Lee Stone, executive director of Advocates for Highway and Auto Safety.

Spokesmen for the Big Three U.S. automakers said they were installing air bags on their own initiative.

None endorsed the bill, however, and Chrysler Corp. spokesman John Guiniven said the company opposed "legislative mandates for specific designs or systems like air bags."

General Motors Corp. said it was studying the bill, and Ford Motor Co. said Congress, in considering the issue, should "recognize the importance of flexibility to accommodate new car and truck introduction schedules."

The automakers said air bags don't save lives by themselves.

"People must buckle up," the GM statement said. "Safety belts are available in vehicles now, and are proven lifesavers."

But the bill's sponsors said there was growing evidence that the air bag offers greater protection than the automatic belts, although federal regulations consider them equally effective.

"Air bag-equipped cars are unquestionably safer," said Sen. Richard Bryan, D-Nev.