FORT LAUDERDALE, Fla. -- Air bags lower the number of traffic fatalities significantly, but they need improvements to prevent injuries and deaths caused by the bags' explosive inflation, a study shows.
A study by the Insurance Institute for Highway Safety found air bags reduce deaths in front-end crashes by about 24 percent.
But the devices also caused problems, including some serious injuries and several deaths, the institute said.
"The principal concern is injuries caused by contact with air bags in crashes of relatively low severity," said the report, released yesterday. "In these situations, it's possible that no injuries at all would have occurred without the air bag."
Researchers believe that injuries caused by an air bag in a severe crash are less serious than those that may have been sustained without the bag.
The institute examined thousands of crashes, comparing cars equipped only with seat belts to automobiles with seat belts and air bags. "The overwhelming conclusion at this time is that air bags are saving many motorists' lives," said institute President Brian O'Neill.
Millions of cars have air bags, which are designed to open in crashes equivalent to hitting a brick wall at about 10-12 mph. The bags unfold at speeds of more than 100 mph with a controlled explosion in the steering column. About 90 percent of 1994 model cars have air bags and all new cars must have them by 1997.
But despite the bags' lifesaving potential, injuries are a continuing problem, the institute report said.
Most injuries reviewed by the institute were called minor under a system that rates whether they are life-threatening -- the same system used by the federal government.
One "minor" injury, for example, was sustained by a 22-year-old man whose vision was damaged when an air bag lacerated his retina, causing bleeding. "His vision may be permanently blurred," the report said.
But the study found some air bag injuries were serious, under the government's threat-to-life rating scale.
In a 1992 accident reported in the New England Journal of Medicine, an air bag ripped a hole in the heart of a 22-year-old woman during a low-speed collision. She survived, but she required surgery and 11 days in the hospital.
Eight deaths also appear to have been caused at least partly by the force of an air bag, the study said.
Two who died were children. In one crash, "the inflating passenger-side air bag may have propelled the child into fatal contact with the vehicle's rear-view mirror and roof," the report said. The child was not wearing a seat belt.
Late last year, the federal government estimated 25,071 motorists had been injured by air bags between 1988 and 1991. About 96 percent of those injuries were rated minor.
To reduce injuries, air bag manufacturers may need to make technical improvements to the bags, including slowing the speed at which the devices open, the institute said.
Problems aside, though, air bags used with seat belts are the best protection motorists have, experts insist. "Air bags are at least as effective as we expected," said Chuck Hurley, senior vice president of the insurance institute.