Quest is on for one-size-saves-all air bag 'Smart' device could adjust to location, height of occupants

November 14, 1996|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

A small but growing number of children and small adults are being killed by automobile air bags, so automakers in the United States are asking the federal government for permission to reduce the bags' potentially lethal punch.

That would save lives and reduce injuries in low-speed crashes, some safety experts say.

But they worry that the price would be the lives of some larger adults in higher-speed crashes.

"What they're proposing is to trade off some of the heavy adults for the little children," said Dr. Carl C. Clark, an auto safety consultant, retired safety engineer and early developer of the air bag.

Even existing air bag standards, he argues, are inadequate: "They should call them the 'half-speed, half-dead standards.'

"They only test to 30 mph, and they say you're safe if you have a very serious injury but you're still alive."

Automakers, air bag suppliers and government officials were to meet today in Toronto to seek consensus on the best way to produce safer, or "smarter," air bags.

Air bags have saved an estimated 1,100 American lives since 1986.

Most of the time they work without causing injuries or deaths of their own.

The National Highway Traffic Safety Administration found no injuries in 58 percent of the 782,000 air bag deployments nationally between 1989 and 1995.

Of the 328,000 deployments that did cause injuries, 97 percent were minor sprains, scrapes or bruises. Just 2 percent were moderate injuries, including concussions and fractures of the ribs, sternum or arms. Only 1 percent were serious or fatal.

But with more cars with air bags on the road each year, crash data have begun to show an increasing number of children and adults who die because they are too close to the bags, which burst from their housings at speeds up to 200 mph.

Through September, 19 adults and 26 infants and children had perished from air bag injuries in low-speed crashes that would not otherwise have been fatal.

Most at risk are unbelted children in front passenger seats, infants in rear-facing front seat restraints, and short, female drivers who sit too close to the steering wheel.

The problem

To work effectively, air bag systems must sense a frontal crash, measure its severity, decide whether to deploy and inflate, all in the milliseconds before occupants -- still moving at driving speeds -- strike car parts slowed by the impact.

That requires inflation by an explosive chemical reaction. The unbelted body can then "ride down" -- decelerate -- on a fully inflated air bag. The crash energy is dissipated as the body deforms the bag, rather than by the car's interior deforming the body.

But if the air bag is still expanding when it contacts the head, neck or chest, the consequences can be terrible:

If you're short, and too close to the wheel, the air bag inflates under your chin. Andrew H. Card Jr., president of the American Automobile Manufacturers Association, has said the resulting injuries "mimic a hanging."

The explosively expanding air bag slams into the chin and neck. That causes a "hyperextension" of the neck, breaking the spine from the base of the skull.

According to the Insurance Institute for Highway Safety, women less than 5 feet 5 inches tall seem especially vulnerable because they slide their seats forward to reach the foot pedals.

Of the 19 adults killed by air bags, 15 were such "short" female drivers. (Some actually are relatively tall. The average American adult female in 1990 was 5 feet 3 3/4 inches tall.)

Crash analysts found other victims who were unbelted and slid forward during pre-crash braking.

Taller drivers sitting too close to the wheel experience what analysts call "punch-out." The air bag explodes into the driver's chest, causing multiple rib fractures and heart and lung injuries.

NHTSA investigated the air bag deaths of 19 children ages 3 to 9. Of the 19, only three wore seat belts. Two of the three wore lap belts only. All 19 were in the front passenger seat, or standing at the dashboard. All were knocked forward by pre-crash braking. The air bags fired, causing fatal head and neck injuries or catapulting the children into interior surfaces.

The seven infants who died were in rear-facing child restraints. They suffered fatal head injuries when the air bag slammed into the back of the restraint.

Early warnings

Auto manufacturers say they warned the government of such dangers when they began testing the technology in the 1970s and more recently as real crash data began coming in.

"Our message has been consistent. There is a risk," said C. Thomas Terry, director of safety affairs and regulations for General Motors.

But Joan B. Claybrook, who was NHTSA administrator from 1977 to 1981, insisted her agency had "no knowledge of any problem of this sort" when she took office.

It did not surface, she said, until 1978, when General Motors presented evidence from tests with piglets that there might be a risk to children at the dashboard. Then, she said, "we took this extraordinarily seriously."

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