air bag

nothing Update [posted 11/18/97]
The federal government has decided to allow drivers and mechanics to deactivate passenger-side air bags if the vehicle must be used to transport children or small adults in the front seat. The ruling "marks a conspicuous U-turn on air bags, under a new federal policy" the New York Times wrote today. Read the details at the National Highway Transportation Safety Administration.
thumbsdown _A fatal friend?
The death of a Tennessee child last October demonstrated that air bags can kill people, even those who are belted into place. The case attracted headlines because most of the 51 people killed by air bags in the United States had not been using seat belts. airbagThat single death changed the whole picture. No longer was the question on the table: "How can we protect people from their own urge to disobey warnings?"

Now, the question is this: Are we riding with a killer disguised as a friend?

The specter of safety equipment killing children is not just alarming to parents. The prospect of being squashed like a bug by a hot, 150- mph balloon also raised a backlash against air bags, a safety measure that has been subject to bitter dispute. One reader of Business Week magazine called them an "example of government regulation gone crazy." Another said, "There is no way to make the automotive air bag anything other than an inherently dangerous fail-unsafe explosive device."

For some people, the prospect of a mushrooming air bag was even scarier than the prospect of being thrown against a dashboard or windshield at 65 mph. In fact, a new survey released Feb. 2, 1997, showed that only 57 percent of consumers considered air bags an important factor in deciding to buy a car, down from 82 percent the year before. And fully 24 percent -- up from 6 percent -- said the lifesaving technology was not important at all in the purchase decision.

The problem of child deaths is getting worse as passenger-side bags gain market share: 10 kids were killed in 1995, but 18 died in 1996. Fewer drivers are being killed by the safety measure, however. Just one of the 19 driver deaths occurred in the 28-million cars built in 1995 and 1996, all of which had dual air bags.

If you're getting ready to dump your air bags, keep reading. The government estimates that as of November 1996, air bags had saved the lives of a net of 1,481 drivers and 133 passengers (that's people saved minus people killed). Like the much smaller death toll, "life toll" is rapidly increasing as more cars carry dual air bags. Want an overview of the highway death toll?

nothing A good friend.
thumbsup In total, says the National Highway Traffic Safety Administration (NHTSA), air bags reduce fatal injuries by 11 percent for drivers and 13 percent for adult passengers. When air bags and seat belts are compared to no protection, the comparison is dramatic: "The latest studies indicate that occupants protected by safety belts and air bags are 50 percent less likely than unrestrained occupants to suffer fatal or serious injury in a crash."

Fell asleep at the wheel?
Tricked ya. We just quoted the Federal Register and you're still awake. Guess the world's #1 insomnia antidote is falling asleep at the switch. But back to our story.

The federal standard is to protect the average male dummy Even though air bags are saving lives, the status quo is not acceptable if kids are being killed by safety equipment. Yet safety experts insist that the recent information is not really a surprise. "In the early 1970s, we knew that children and out-of-position adults would pose a problem," says Steven Batterman, a University of Pennsylvania expert on auto restraint systems. In addition to proper design, every product in such wide-scale use needs "feedback from the field and fine-tuning," Batterman says, and air bags are no different.

He lays the problem to auto-industry sluggishness: "If GM had not waited these 20 years [to introduce air bags], a lot of these problems would have been ironed out by now."

Kyle Johnson, GM's spokesman on safety issues, rejects that argument, saying GM was reluctant to introduce air bags from concern about just the kind of problem that's now surfacing, combined with a preference for an easier route to the same goal -- reduced fatalities. "Industry didn't feel that it would save as many lives, and felt that mandatory seat belt laws would save more lives," Johnson says. Air bags were installed on some 1973 Fords and GM cars bought by the government, Batterman adds. "Every now and then you hear about one being deployed, saving somebody in an accident."

Still, ironies abound in the airbag story. They were first proposed in the late 1960s as primary safety systems, so the bags were made powerful enough to protect a 170-lb., 5-foot 9-inch man who was, like 90 percent of drivers, not belted into position. "The federal standard is to protect the average male dummy," says Johnson, alluding to the crash-test dummies auto makers use to assess safety in test crashes.

But times have changed, and seat belt usage has reached 68 percent. "But," Johnson notes, "we've still got this standard that is putting some people at risk while protecting somebody who is breaking the law in 49 states and the District of Columbia."

Gaining momentum

Click on the small image to view the
gif animation simulating a crash with air bags and seat belts.
Courtesy
of the National
Crash Analysis Center [407K and 396K]
side viewAuto accidents are a study in changes in momentum. According to Newton's laws, a body in motion (like a car or a passenger) tends to remain in motion, until it is acted upon by an outside force. That's why it doesn't feel like you are going 65 mph when you're cruising the highway -- because it's a steady 65.

top view But if you suddenly have to brake for an accident, you'll feel yourself sliding forward in your seat. What's happening is that the car is slowing as its velocity is changed by the external force of the road on the tires, but your momentum continues pushing you forward. Eventually, an external force-- your hands on the steering wheel, your butt on the seat, or your seat belt, will supply the "external force" that slows you down. Similarly, when you speed up, it's the seat back that gives an external force that changes your velocity (that's a fancy term for speed in a certain direction).

The problem is, the faster your change in momentum, the greater the chance of injury. Furthermore, the harder the object that forces you to change momentum, the more you'll be hurt by it.

Wearin' that seatbelt
That's where seat belts and airbags come in. They make a soft (and in the case of air bags, broad) surface that's far less injurious than the typical dashboard or windshield.

According to University of Wisconsin-Madison child-safety expert Murray Katcher, motorists only have to remember three rules to reduce most of the children's risk from air bags. 1)All kids in the back seat. 2) Never put a rear-facing infant seat in the front seat. 3) If a child absolutely must ride in front, use proper restraints and slide the seat all the way back. Even though air bags were historically designed for unbelted passengers, now they're supposed to work in combination with seat belts. The seat belt holds you in position while the air bags provides a softer, more cushioned stopping agent. (Seat belts are also needed in side and rear collisions, and in rollover accidents, where air bags don't inflate.)

One of the problems of not being belted arises from where the air bag hits you. They're most effective when they strike the torso. Says Roy Alson, an emergency medicine physician in Winston-Salem, N.C., if it hits the head and neck, it can hyperextend the neck and cause significant injuries.

Source: University of
Wisconsin-Madison
child-safety expert
Murray Katcher.
And that's the calculus that puts smaller people at risk: "The serious and sometimes fatal injuries that we have seen have been injuries to the head and neck in smaller individuals," Alson says.

Many solutions have been proposed to the problem: shutting off the bags, taking some of the steam out of them, or giving the bags enough brains to "see" who's in the seat. There's talk of using the classic half-solution to bad design: warning labels. Some experts have even mentioned that the kids should go in the back seat.

We'll get to these in a moment, but first, we got to wondering how air bags actually work. Are they filled with dynamite or something equally dangerous?

And why do they cover you with that weird white powder?


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