In Harm's Way

By DONALD W. NAUSS

Aug. 19, 1996 12 AM PT

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TIMES STAFF WRITER

DETROIT — Driving with his three children just a few blocks from his Baltimore home last October, Robert Sanders leaned forward to change the radio station.

Briefly distracted, he didn’t see the red light until it was too late. He slammed on the brakes and skidded into another vehicle. The crash wasn’t severe--Sanders said he was only moving about 10 mph at impact--but it was enough to set off the air bags in the 1995 Dodge Caravan.

Sanders and his two sons, who were seated in the rear, were unhurt. But his 7-year-old daughter, Alison, riding in the front passenger seat, was knocked unconscious by the inflating air bag. She died the next day from severe head injuries.

“I found out the hard way that the benefit of air bags to children is far outweighed by the dangers,” said Sanders.

Alison Sanders is among 24 passengers--all but one of them children and infants--killed by air bags since 1993. The crashes were at low speeds and would not have caused serious injury if the air bag had not fired.

The cruel irony of children being harmed by a technology that every year saves 500 lives is driving a push by auto engineers and regulators to develop “smart” air bag systems.

These intelligent electronic systems can determine whether seats are occupied or not, the size and position of passengers and whether seat belts are buckled, then deploy the bags on a virtually customized basis to provide the best protection possible given the crash circumstances.

The National Highway Traffic Safety Administration is considering mandating new smart technology to eliminate the danger posed by the bags, which inflate in a tenth of a second at speeds of up to 200 mph.

Rudimentary smart air bag systems have already begun appearing. Mercedes-Benz will introduce in its new SLK roadster a system that will stop air bag deployment if a rear-facing infant seat--the source of many bag-related injuries--is detected in the passenger seat.

More intelligent air bag systems are under development and are expected to appear in new vehicles within the next two to five years, auto industry executives say. The most sophisticated systems, which integrate front and side air bags with advanced seat belts and radar-based crash-avoidance systems, could take up to a decade to perfect.

Though air bags have clearly been a success, they have always been controversial. The auto industry fought them for years, voicing fears of accidental deployment and lawsuits and complaining that customers wouldn’t want to pay for them.

Finally in 1984, then-Transportation Secretary Elizabeth Dole ordered that 1990 vehicles must have either automatic seat belts or air bags. Consumers disliked the automatic belts, and air bags were embraced when then-Chrysler Chairman Lee Iacocca--a longtime air bag critic--made them standard equipment in some vehicles.

In 1991, President George Bush signed a law requiring driver and passenger air bags in all new cars by September 1997 and in all new trucks a year later. The safety devices have proved so popular that virtually all new cars already have dual air bags as standard equipment.

Today, about 35 million cars on the road are equipped with driver air bags and 15 million have passenger air bags. In the next five years, 30 million more cars will be equipped with dual air bags.

And as their numbers grow, their shortcomings are magnified.

The possibility of injury from air bags has long been known. Most injuries are relatively minor--small cuts, abrasions and bruises. More severe ones ranging from broken bones to eye injuries also occur, particularly to individuals seated too close to the bag or not wearing seat belts.

The number of severe injuries and fatalities is rising steadily. A recent analysis by Ted Miller, a safety economist who does research for the NHTSA, concluded that twice as many children will be killed by air bags this year as will be saved by the devices. The agency does not dispute the finding.

“We are concerned as we look down the road,” said Philip Recht, NHTSA deputy administrator. “The number of injuries could multiply as more vehicles are equipped with air bags.”

Those most in danger are infants in rear-facing child seats and unbelted or improperly belted children. But since 1990, 18 drivers have also been killed by air bags, mostly small elderly women seated close to the steering wheel.

Researchers looking for solutions to the problem are now focusing on “occupant sensing” technology. Using an array of electronic sensors, these smart systems can determine the size and position of a passenger, whether the seat belt is buckled and the severity of the impending crash. These data determine whether or not to deploy the air bag, and if so, at what speed--even in what direction.

“We can have air bags that inflate differently for different persons,” said John Miller, manager of advanced restraint systems for AlliedSignal, an air bag maker. “For a small, light person, the inflation will be less aggressive than it would be for a larger, heavier individual.”

Current air bags are designed only to deploy in frontal crashes where the force of the collision is equivalent to running into a stationary barrier at 9 to 14 mph. Federal standards require air bags to protect an average adult male not wearing a seat belt in a head-on crash. So the deployment is at the same speed and force regardless of the passenger’s size or closeness to the bag.

“An air bag today hits a 40-pound person with the same force that it hits a 190-pound person,” said Andreas Hirl, senior marketing analyst for Siemens Automotive, an air bag supplier.

The most immediate challenge is rear-facing child seats. Warning labels alert parents that such seats should not be placed in the front passenger seat because a deploying bag could hit the back of the seat hard enough to cause severe neck or head injury to an infant.

But many consumers ignore such warnings. Others have pickup trucks or sports cars without back seats. As a temporary solution, the NHTSA has allowed auto makers to install a cutoff switch that allows the passenger air bag to be turned off when a rear-facing child seat is used. Ford has installed such a system in its F-Series and Ranger pickups.

Mercedes-Benz will install in its two-seat SLK roadster--a 1998 model to be introduced in early 1997--the first smart system that can detect the presence of a rear-facing child seat and automatically deactivate the passenger air bag.

The system, developed by Siemens and IEE Automotive, works much like the security tag system used by clothing retailers on merchandise. Antennas embedded in the passenger seat send out an electromagnetic signal that is reflected by resonators in the child safety seat. If the signal is returned, the air bag’s electronic control unit is told to deactivate the bag. If no signal is returned, the system knows no safety seat is present and the air bag stays on.

“It’s a crude system,” said Alfons Hartl, general manager of vehicle electronic systems for Siemens. “But it’s the first step to smart air bag systems.”

Another step is the development of passenger detection systems. One system, already used by BMW and Mercedes-Benz, uses a load-sensitive resistor consisting of two polymer films that, when pressed together, electronically measure weight.

If more than 25 pounds is detected in the passenger seat, the system assumes it is occupied and will deploy the air bag in a collision. The system was developed in Europe to reduce repair costs by preventing the deployment of the passenger air bag when the seat is empty.

But U.S. regulators believe the system can easily be adapted for safety protection. They have proposed calibrating the weight sensor to 66 pounds--the average weight of a 9-year-old--to prevent deployment should a smaller child be in the passenger seat.

Industry officials, however, say it is difficult to properly gauge an individual’s weight precisely because so much depends on how one is sitting. For instance, a person might be measured at different weights if he is seated on his knees or on the front edge of the seat.

“This system was not designed to be a safety system,” said Fred Heiler, a Mercedes-Benz spokesman.

More sophisticated smart systems--likely to add $100 to $300 to the cost of a car--are under development using a new generation of air bag inflaters and an array of sensors that judges occupant position, seat belt usage and crash severity.

Siemens, TRW, Robert Bosch, Takata and Delco Electronics are among those testing occupant-position sensing systems using ultrasound, infrared, acoustic and other technologies.

TRW, for example, is developing a system that relies on ultrasound technology. Sensors in the front of the passenger compartment emit an inaudible sound-wave beam up to 100 times per second. The wave pattern provides a “map” of the passenger’s position.

“It’s the same principle as range detection in a camera,” said Roger McCurdy, TRW’s chief engineer for electronic safety systems.

Takata, Bosch and Siemens are all testing infrared sensors, which send out heat-sensitive electronic signals that yield a constantly changing picture of an occupant’s position. Bosch is also using acoustic sensors that detect movement.

“With these sensors we can recognize inanimate objects, like rear-facing child safety seats,” said David Giroux, spokesman for Ford, which is working with Bosch on an automatic passenger detection system. If a safety seat is detected, the bag is not deployed.

The biggest obstacle to smart air bags is reliability. Occupant sensing is a highly complex technological problem because so many variables exist. How does the system react when a passenger is properly seated but puts his hand on the dash? Can the system adequately recognize a passenger reading a newspaper? What happens if the sensor is blocked?

“The big challenge is how to handle all the special circumstances,” said Jon Kelley, staff engineer supervisor for Delco Electronics, a unit of General Motors. “Right now, there is no perfect system.”

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

ON THE ROAD TO SMARTER AIR BAGS

Air bags are credited with saving more than 500 lives a year but are also blamed for injuries and deaths, especially of small children. Now auto makers are developing “smart” air bags.

NEW DEVELOPMENTS

* “Smart” systems: The first rudimentary “smart” systems can recognize the presence of a rear-facing child safety seat and automatically deactivate the air bag. Mercedes-Benz will introduce such a system this fall on its 1997 SLK roadster. A sensor in the seat detects a resonator in the child seat.

* Weight sensor: Another Mercedes system has a weight sensor that determines if the passenger seat is occupied. If it detects a weight of more than 26 pounds, the sensor assumes the seat is occupied and the bag is deployed in a crash. U.S. regulators would like the sensor to be calibrated to 66 pounds to protect bigger children.

* Other sensors: More sophisticated systems will have dual-stage inflaters that allow air bags to be inflated at varying speeds. Using infrared, ultrasound and other technologies, the systems can detect the presence of an occupant, the passenger’s weight and position and whether the seat belt is buckled. A control unit in the passenger compartment decides within milliseconds whether to deploy the bag, the optimal inflation speed and even the direction.

* Safety restraint systems: Ultimately, smart bags will be incorporated into a larger safety restraint system. They will work in conjunction with advanced seat belts that tighten instantly when a crash occurs and then slowly release the passenger into the bag. The system will also be aided by radar-based crash-avoidance systems, side air bags and potentially knee-level and rear-seat air bags.

AIR BAG DANGER

Since 1990, 18 drivers and 24 passengers have been killed by air bags. All but one of the passenger victims were children.

Driver fatalities caused by air bags

1990: 1

1991: 3

1992: 2

1993: 3

1994: 5

1995: 4

Passenger fatalities caused by air bags

1993: 1

1994: 5