Industry to NHTSA: power down on air bags

The auto industry and the federal government have boxed each other into a neutral corner of the air-bag regulation arena, and it will take several years for the combatants to extricate themselves. Meantime, young children sitting ringside are in danger.

The dilemma? A National Highway Transportation Safety Administration (NHTSA)-mandated safety device (the passenger-side air bag also can kill kids.

The industry favors a less aggressive air-bag deployment - powering down as it's known in the vernacular - until more sophisticated air-bag systems are available. NHTSA proposes that vehicles without smart passenger-side air bags be required to have warning labels, a manual cutoff switch for the passenger-side bag and require clearly visible warning labels on rear-facing child seats. The agency also is proposing that air bags not deploy when a person who weighs less than 66 lbs. (30 kg) is in the passenger seat.

"We,re trying to encourage the development of smart air bags," says L. Robert Shelton, NHTSA's associate administrator for safety performance standards. "And there's a lot of technology development going on in the area."

Since the 1991 ruling that requires driver- and passenger-side air bags in all cars by September 1997 and in light trucks by September 1998, at least 21 children have sustained fatal neck and head injuries due to passenger-side air bag deployments. Six of the deaths involved rear-facing child seats and 15 apparently occurred because the children were improperly belted.

Government, automaker and supplier officials agree that "smart" air bag systems will solve the problem of unnecessary and dangerous air bag deployments, but they differ on the definition of a "smart" air bag. NHTSA defines a smart system as one that uses sensors and electronics to prevent air bags from deploying in situations dangerous to children. Automakers and suppliers generally define smart bags as those that actually tailor deployment for optimum protection depending on each specific incident.

Although such technology is being developed now, the earliest smart air bag vehicle would come between 1999 and 2002. The real debate concerns what to do in the interim. The auto industry supports a less-aggressive air bag deployment because NHTSA itself reports that 70% of the nation's motorists wear safety belts. Other experts say air bags should deploy only in higher-speed crashes, because seat belts alone are effective at lower speeds.

In August, the American Automobile Manufacturers Association (AAMA) petitioned the government to amend Federal Motor Vehicle Standard (FMVSS) 208 to permit slower-deploying air bags. AAMA also proposed a new sled test to replace NHTSA's 90-degree, 30-mph (48.3 km/h) vehicle crash test into a fixed rigid barrier. One of the main arguments AAMA has with the current test is that it is designed to protect two unbelted adult crash test dummies. To meet the test criteria air bags must deploy at 200 mph (322 km/h).

In September, NHTSA performed an experiment using the AAMA's proposed sled test and reports that the test is so easy to pass that dummies escaped injury without an air bag or even seat belts.

New test or not, automakers are opposed to expanding the manual cutoff switch to vehicles with rear seats and also are against more warning labels. Even noted Detroit trial attorney Harry Philo says the NHTSA proposal has flaws, but urges action nonetheless.

"(NHTSA's proposal) really presents problems including misuse of the cutoff switch," states Mr. Philo, whose litigious experience dates back to the Chevrolet Corvair. "But you've got a hazardous situation for a certain group of people. If the situation is foreseeable and can be reasonably prevented or minimized, then you must act."

So the debate rages on.

"Chrysler believes de-powering of air bags will reduce child injuries and fatalities more quickly than any other means," says Dale E. Dawkins, Chrysler Corp.'s director of vehicle compliance and safety affairs, in the company's official comments on the proposed ruling. "We can begin depowering at least some vehicles within the next year and rapidly phase in the rest."

Bill Eagleson, Ford Motor Co.'s manager of occupant protection and vehicle dynamics, says that "We think NHTSA should look at the AAMA proposal and include the driver's side."

Mr. Dawkins says Chrysler is against more warning labels because neither the automaker nor NHTSA has any data showing that they change occupant behavior.

Messrs. Dawkins and Eagleson agree with Mr. Philo on the potential for misuse of cutoff switches. Mr. Eagleson adds that many questions still must be answered before a strategy to implement smart air bag technology can be started. "Technology often is developed in stages, so do we implement in stages or wait and do it all at once?" he asks. "Does it make sense to retrofit existing vehicles or wait until a vehicle is redesigned?"

Clearly the domestic automakers are not sold on the advanced air bag technology available from suppliers today.

"Many alternatives have been presented to us for occupant-sensing systems that would assure that a passenger-side air bag system would not deploy in a collision if the passenger seat were occupied by a rear-facing child restraint, and yet would deploy if it were not," says Chrysler's Mr. Dawkins. "We have not yet been convinced that any of the systems proposed are reliable to the extent that we require. We believe that such systems are years away from production."

Mr. Eagleson adds that "There are systems in development, but the challenge is making them feasible for high-volume production, repeatable and reliable. We're working as quickly as we can to make them feasible. But there is nothing we see on the horizon to control deployment."

While at least two domestic manufacturers are claiming smart technology (by their definition) is not available (General Motors could not be reached for comment), Mercedes-Benz and BMW have equipment in their 1997 vehicles that meets NHTSA's definition of "smart."

Mercedes and BMW vehicles are equipped with Siemens Automotive's passenger-presence detection system, which uses a weight of sensor in the passenger seat. If the sensor detects weight of more than 27.5lbs. (12.5 kg) a signal activates the air bag. An empty seat or a weight less than that will keep the passenger-side bag, from deploying.

The German vehicles also are equipped with device called Baby Smart, which detects the position of a child safety seat if it is tagged with a special transmitter.

Suppliers agree with their automaker customers about the development of smart systems. To really tailor air-bag, deployment to specific situations, sensors that measure crash severity and the occupant's proximity to the instrument panel are needed.

Suppliers are using various approaches to these problems. TRW, for instance. is working on an ultrasonic passenger-presence and position sensor. "Various sensing technologies have been evaluated by TRW, the most robust of which employs the use of ultrasonics," says the company in its official comments to NHTSA. "If a coordinated effort could be initiated shortly, implementation of this approach might commence around model year 2000 or 2001."

Morton Automotive says it is developing inflators that can provide variable performance in response to signals from the sensing/firing part of the air-bag system. "The use of a position sensor, possibly in conjunction with a weight sensor. offers the greatest potential for reducing deployment-induced injury to both children and adults," says the company, adding that its smart inflators will be available for 1999 model-year vehicles.

AlliedSignal Automotive says the need for multi-stage inflation prompted the company to resurrect a product that was ahead of its time.

"Several years ago we developed a dual-stage inflator and it has been on the shelf because there was never a demand for it," says Wendell Lane Jr., director of engineering for AlliedSignal's safety restraint systems. "We,re prepared to deliver engineering samples to OEMs, today and have done so."

Mr. Lane says the problem isn't so much the staged inflation, but rather the sensing. He says AlliedSignal has successfully tested a sensing system called Capaciflector, which monitors occupant position via seat-mounted and IP-mounted sensors that sense the electrical capacity of a human (which is made up mostly of liquid). It won't be production-ready until 2002.

Another Alliedsignal innovation could be a stop-ap solution. an air bag with special vents sewn in such a way that if the bag contacts something too soon during deployment, the vents open and dramatically slow the bag's deployment. The slow down issignificant enough to see a dramatic reduction in head-injury testing criteria," says Mr. Lane. "At least one OEM is looking at (the vented bag) as a temporary mechanical solution." But not before 1998 or 1999.

Perhaps the best new idea for tailored inflation comes from a small Utah-based company called AirBelt Systems LLC, whose president, Chuck Fenton, spent six years studying air bag inflation as a Morton vice president.

Mr. Fenton says he has invented an inflator that uses a patented throttle device called IntelliFlow, through which inert helium is blown to tailor air-bag deployment. The device, he explains, takes information from sensors and releases the helium through various holes in the inflator to adjust the flow of gas to the bag.

"In the past, the release of cold gas was an uncontrolled event," says Mr. Fenton. "Now, we can put more pressure in a DOT-approved bottle and control the output. We have proven the concept and are past prototypes."

He further claims that his inflator can deploy at 60-80 mph (96-128 km/h) in the first 15 to 20 milliseconds of deployment (a less-lethal speed to children than 200 mph) and still meet FMVSS 208.

Other companies including Morton also are working on gas-generated, non-azide inflators.