Washington ? Terri Vaccher was driving along a California freeway in 1997 when a truck jackknifed in front of her. As her sport utility vehicle plowed into the truck, the expectant mother saw a white light and thought her life was over.

It turned out that light was an air bag deploying. One of Vaccher’s legs was crushed from the impact, but her son was born healthy the day after the accident.

“I completely attribute my life and my son’s life to the air bag and to the seat belt,” said Vaccher, 38, a property manager from Fullerton, Calif.

Vaccher is one of the 15,000 people the government estimates have been saved by air bags since then-Transportation Secretary Elizabeth Dole signed an order on July 11, 1984, requiring all vehicles to have driver’s side air bags or automatic seat belts by 1989 and passenger-side bags soon after.

To get the rule, which was opposed by the auto industry because it would add cost to vehicles, Dole promised it would be rescinded if states that accounted for two-thirds of the population passed laws requiring seat-belt use.

Dole, now a Republican senator from North Carolina, said tying seat-belt use to air bags made sense in an era when the national seat-belt use rate was just 13 percent, compared with 79 percent today.

“It was my goal to achieve fundamental progress in both air bags and safety belts and I am pleased that that is what has happened,” Dole said.

The rule followed fierce debate between air bag advocates and the auto industry, which objected to the cost and warned that because the devices deployed with such force — many at well over 100 mph — they could harm people, particularly children. The warning was prophetic: 242 deaths — many of them children or small women — are blamed on air bags.

Deaths peaked in 1997, when 53 people — including 31 children — were killed.

Dr. Jeffrey Runge, who heads the National Highway Traffic Safety Administration, said those deaths were one reason NHTSA is slowly phasing in a regulation requiring side air bags by 2009.