That's according to a new study by Washington researchers who found that simply buckling up lowers the chances of dying by 65 percent, compared with not wearing a restraint at all.
Front air bags cut a driver's risk of dying in a car crash by roughly 8 percent versus not having the inflatable devices. The combination of seat belts with air bags was safer, but only marginally so.
"You are 'way better off if you have a seat belt, and you get a slight further advantage if you have an air bag," says Dr. Peter Cummings, an epidemiologist at the University of Washington and lead author of the study. "Regardless of that, you should wear your seat belt unless you don't care about your risk of death."
Cummings and his colleagues, whose findings appear in the latest issue of the British Medical Journal, analyzed records from more than 51,000 vehicles -- carrying 102,000 drivers and front-seat passengers -- involved in crashes on U.S. roads. All the wrecks, which occurred between 1999 and 2000, ended in at least one death.
Sixty-three percent of the vehicles had no air bags, 20 percent had both driver and front passenger bags and 17 percent had only a driver's side bag. Most were passenger cars, although some were sport utility vehicles, light trucks and vans. About two-thirds were built in the early 1990s, before passenger-side air bags were mandatory and side airbags were widely available.
Drivers with an bag to cushion them were 8 percent less likely to die in a wreck than drivers who didn't have an air bag, the researchers found. Both wearing a seat belt and having an air bag didn't change the odds much.
One unexpected finding: Women drivers were less likely to be killed if they had an air bag. Their odds of death dropped 12 percent compared with 6 percent for men. That was a surprise, Cummings says, since anecdotal evidence hinted that women, who are typically smaller and lighter than men, might be at increased risk of injury and death from deploying air bags.
"It was the opposite of what we expected. One of the reassuring things in this study is it appears that the protection from air bags is at least as great if not greater for women than for men," he says.
Air bags proved most effective in head-on and other front-end collisions. Older drivers, and especially older women, gained more from air bags than younger motorists. Why that's true isn't clear, Cummings says.
But seat belts offered the best defense against death -- so much so that adding an air bag to the equation dropped the risk of dying only another three percentage points, the researchers say.
"What's important for consumers to know is that you can't separate air bags and seat belts," says Russ Rader, a spokesman for the Insurance Institute for Highway Safety. "They work together to reduce your risk of injury or death in a crash."
The job of a seat belt is to keep a motorist in place as much as possible during a collision. The air bag helps by preventing what movement that does occur from throwing a person against the solid parts of the vehicle's interior, giving them a soft cushion instead .
Transportation officials wouldn't comment on the specifics of the study. But a spokesperson for the National Highway Traffic Safety Administration (NHTSA) called the results "generally consistent with our findings."
Auto accidents cost the U.S. economy more than $230 billion in 2000, according to a new NHTSA report. That works out to an average of $820 for every man, woman and child in America.
In 2000, when more than 41,800 people died on the nation's roadways, seat belts prevented some 11,900 additional deaths and 325,000 serious injuries, the report says. Failure to wear the restraints accounted for an estimated 9,200 avoidable deaths and 143,000 injuries, at the cost to society of $26 billion.