- The Washington Times - Friday, June 2, 2000

DETROIT As the American desire for pickup trucks and sport utility vehicles has grown, so have injuries and deaths from accidents in which the vehicles roll over. Technology developed in Europe, however, might offer automakers a way to improve stability quickly and cheaply.

Electronic stability-control systems, which use a set of sensors to keep a vehicle from spinning out, are gaining in popularity in Europe and are increasingly being included on passenger cars. But pickups and SUVs might benefit more from these systems, since those vehicles are more prone than cars to rolling over and are more likely to cause a fatal accident when they do.

The electronic stability systems "look very promising," said Brian O'Neill, head of the Insurance Institute for Highway Safety. "They appear to work very well on test tracks, and they do seem to, under those controlled conditions, limit the likelihood that a vehicle will get going sideways in a loss of control, which is the typical precursor to a rollover."

So far, only two luxury SUVs have such systems the Mercedes-Benz M-Class and BMW X5. But other automakers, including General Motors, Ford and Toyota, are installing them in some of their vehicles.

Although different companies manufacture the systems, each takes anti-lock brakes and adds three sensors to it one each for steering wheel angle, vehicle spin or "yaw" and turning force. Engineers program each system with data about which direction the vehicle should go at a certain speed when the steering wheel is turned.

When the system detects the vehicle moving in a direction that doesn't match the stored data, it briefly applies a brake to one wheel. The result is a car that doesn't "fishtail" in severe turns or on surfaces with poor traction.

Such systems first gained notoriety in Europe in 1998, when Daimler-Benz AG added it to the Mercedes A-Class subcompact. The micro hatchback smaller than a Chevy Metro rolled over when journalists made a sharp turn during a driving test. Facing a public relations nightmare, Daimler-Benz redesigned the car's suspension and added a stability system.

The publicity from the A-Class debacle sparked customer interest in stability systems and goaded other European manufacturers to offer the feature, including GM's Opel unit, Ford and Volkswagen. Audi added the system to its TT coupe earlier this year after a few high-speed crashes in Germany.

As a result, one of three companies that builds electronic stability systems, Continental Teves, estimates that 30 percent of all European vehicles will have one by 2004. Automakers charge about $600 for an optional system on a luxury car and the price is expected to fall in the next few years.

But industry experts say European cars which are generally smaller and more agile than passenger cars designed for the United States actually see little benefit from electronic stability systems outside of emergencies. The technology might find more use in heavier vehicles that can be harder to control in an emergency or more prone to rolling over such as pickups, minivans and SUVs.

According to federal crash data for 1998, the latest year statistics were available, 9,771 persons died in rollover crashes. SUVs rolled over in 36 percent of the fatal crashes they were involved in more than double the rate for passenger cars. More than 60 percent of the SUV occupants killed in 1998 died in crashes where the vehicle rolled over.

The National Highway Traffic Safety Administration (NHTSA) and automakers have been battling over the agency's plans for a test that would rate a vehicle's rollover propensity, giving them a rating of one to five stars in the same fashion that the NHTSA now rates crashworthiness.

Industry experts say the NHTSA appears to have settled on a fairly simple mathematical formula for its test, based on a vehicle's weight and tire track width. But automakers contend that such a formula won't take into account driver behavior and safety systems such as stability control.

"Technology is moving faster than rule makers can move," said Bob Lange, the engineering director of GM's Safety Center. "I don't think anything prevents rollover other than good driver behavior. Integrated chassis systems can certainly enhance driver control and provide a driver assist at the limit."

Mr. O'Neill said the NHTSA test due out this year would only measure a vehicle's likelihood of rolling over once a crash begins, while stability systems work mostly by preventing crashes. If stability controls are proven to help prevent rollover, the NHTSA should take them into account, he said.

But there's no consensus on just how well stability-control systems will prevent rollover. Most rollover crashes happen because a vehicle leaves the road and trips over an obstruction. In theory, stability control would improve the chances that a driver could keep the truck or SUV on the road.

Mr. O'Neill said safety experts thought anti-lock brakes would reduce crashes, but to their surprise no improvements have been measured so far.

"It's very difficult to project from the test track to the real world because we have the involvement of the driver," he said. "When you get into the real world, drivers sometime subvert the best technology."

But automakers have enough confidence in the systems to offer them as a safety feature. The Toyota Sequoia full-size SUV due out this fall will have a stability system. A GM spokesman said the company will introduce such systems "relatively aggressively" on new truck models.

"The market for safety systems is substantial, the appetite is substantial and manufacturers want to satisfy those appetites," Mr. Lange said. "As a practical matter, what we're going to see is manufacturers applying electronic chassis control systems to trucks and SUVs."

Ford will offer stability control on the 2001 Windstar minivan and an upcoming version of the Focus compact car. Ford spokesman Jon Harmon wouldn't say whether the company would add the system to all its pickups, vans and SUVs, but did note that Ford had announced earlier this year a rollover air-bag system that will be phased in during the next three years.

"One could surmise we could also step up technology for preventing roll through lots of different means, one of which would be electronic stability," Mr. Harmon said.

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