Halting Airbag Deaths

FIVE YEARS AGO ENGINEER TONY Corrado was busy designing smart bombs for the military. Then he heard the first reports of how the explosive power of car airbags was causing injuries and death. As he read up on the problem, he felt certain that technology could solve it. Today Corrado is leading a team of engineers developing ""smart airbags'' that will save lives without hurting people in a crash. ""This is one of the most difficult technical problems ever posed in the auto industry,'' he says.

Luxury carmakers like Mercedes have already installed the first primitive smart bags, which use sensors in seat cushions and seat belts to determine whether the airbag should be deployed. Corrado, a VP at Robert Bosch Corp., is testing models that use more sophisticated sensors. The goal is to turn today's one-size-fits-all airbag into one that customizes its cushioning blast to fit a passenger's size and body position. Big, unbelted folks in a severe crash will get a bag's full blast; smaller people in slower crashes will get a less forceful boom. The researchers' motivation is strong: by 2005 so-called occupant-detection systems will be a $500 million business.

Smart-bag prototypes look deceptively simple. Hidden above the windshield of the Volvo sedan in Corrado's lab are four ultrasonic sensors (the same gizmos used in autofocus cameras) and two infrared sensors (like the ones on auto-flush public toilets). The sensors detect a passenger's body heat and position. Lean too close to the dash and a light comes on, signaling that the airbag has shut off; it senses a child seat the same way. Other suppliers are testing combinations of infrared, ultrasound and capacitors, which detect the water in a human body. But even the best systems can be tricked. Weight sensors can't tell a 30-pound kid from 30 pounds of groceries; infrared can mistake that hot pizza on the seat for a warm body. Capacitors might think a wet towel is a person.

Those problems, along with the automakers' sluggish development cycles and the need for better electronics to process the sensor data, mean it could be five years before a truly smart airbag system shows up in new cars. That's too long for critics like Robert Sanders, whose 7-year-old daughter was killed by an airbag in 1995. He prefers lower-tech solutions, like setting airbags to go off only in more severe crashes. ""This crisis doesn't require Star Wars technology,'' he says. For now, the best safety advice on airbags is extremely low-tech: always wear a seat belt and keep kids in the back seat.