DETROIT — DAN RADLOFF was heading home after a busy day on the road. Pulling off the freeway, he neared the end of the exit ramp when suddenly a pickup truck pulled out from a stop sign directly in front of him. There wasn't time to brake, and Mr. Radloff plowed into its side, pushing the pickup six feet sideways. Stunned, Radloff sat in his car for a moment. Slowly taking account, he realized his only injury came when his right hand smashed into the windshield.
What made the difference between a potentially tragic accident and one in which the Ford Motor Company executive could walk away, shaken but unhurt? A little bag of air that had popped out of the steering wheel of his Tempo sedan, cushioning the impact.
``Everything happened so quickly, I didn't even recall the air bag going off,'' Radloff says.
As the bumper of Radloff's Tempo made contact with the pickup truck, a pair of electronic sensors sent signals to an on-board computer that quickly determined that his car was having a serious accident. The computer ignited a small explosive charge of sodium azide, creating a blast of nitrogen gas. The gas inflated a small nylon bag, which popped out of the steering wheel, cushioning Radloff, and keeping his chest from smashing into the wheel.
All that happened in barely a 30th of a second - three times faster than the blink of an eye.
Primitive air-bag technology first appeared in the late 1960s, but it took more than a decade before federal safety officials felt confident enough to order the use of the devices in passenger cars. Yet another decade has passed, a decade in which auto industry lobbyists and a sympathetic Reagan administration repeatedly delayed the introduction of the devices.
Cost was a major concern, since air bags were initially expected to add at least $1,000 to the cost of a car. Reliability was another factor. Would air bags always work when they were supposed to, and would they accidentally trigger when they shouldn't, critics worried.
Even crash survivor Radloff admits he was a skeptic before his accident. ``My assessment was that they were an additional expensive ordered by the government. Now I'm a firm proponent of air bags.''
So are a growing number of other former critics.
During a recent demonstration of his company's newest air-bag technology, General Motors President Robert Stempel hailed the benefits of the devices. He also noted that ``the 1990 model year will be the first one when air bags will be used by American consumers in large numbers.''
United States and import manufacturers expect to sell about 2.9-million air-bag-equipped passenger cars during the 1990 model-year, up from 700,000 in 1989, and 400,000 in 1988.
THERE are a number of reasons why air bags are coming into greater use. They are proving highly reliable, with not one recorded instance of a bag malfunctioning. And while prices are still high, ``more than $500,'' says Mr. Stempel, that's well below the projections of a decade ago.
Since the 1987 model-year, federal regulation has required automakers to begin phasing in so-called passive restraints, which can include either air bags or passive belts, which automatically envelop front seat occupants before the car is shifted into gear. Come the 1990 model-year, every car sold in the US will have to have some form of passive restraints.
The Chrysler Corp. is taking the most aggressive stand on bags, using them in every one of its American-made vehicles, as well as one import line. Ford will equip about 1-million vehicles - half its 1990 passenger-car fleet - with air bags. GM will lag behind, offering them in about 500,000 vehicles, or about one in six passenger cars.
``By having automatic occupant protection, be it air bags or automatic belts, we could save 9,000 lives a year,'' says Barry Felrice, an official at the National Highway Traffic Safety Administration. That's more than a third of the 24,000 deaths that occur each year in passenger-car accidents.
Experts caution that bags are not a safety panacea, nor a substitute for seatbelts. While 41.5 percent of all fatalities occur during the frontal accidents, for which they are designed, they will not inflate during side, rear, or rollover accidents.