New test to simulate likelihood of vehicle rollover

`Dynamic' trials look at panic maneuvers' effect

October 08, 2003|By Rick Popely and Jim Mateja | Rick Popely and Jim Mateja,CHICAGO TRIBUNE

Federal auto safety regulators are launching a new test to simulate how likely vehicles are to roll over in emergency maneuvers.

The dynamic test simulates a panic maneuver at 35 to 50 mph in which a driver would abruptly turn the wheel left to avoid going off the road and then steer back to the right into the proper lane.

Congress mandated a dynamic rollover test for new vehicles in 2000 in response to nearly 300 rollover deaths attributed to Firestone tire failures. Most of the deaths occurred in Ford Explorer sport utility vehicles.

The National Highway Traffic Safety Administration (NHTSA) will combine the dynamic test with static rollover ratings it has issued since 2001 and publish the results as part of its consumer information program on new vehicles.

The static ratings apply a mathematical formula to a vehicle's height and width to predict how likely it is to roll. NHTSA assigns one to five stars, with one indicating the highest probability of rollovers. Passenger cars typically earn four or five stars in the ratings, and SUVs two or three stars because of their higher centers of gravity.

The auto industry said the simulation is better than static ratings but added it needed time to evaluate the test before endorsing it.

"The test is better than just a mathematical formula that only takes into account how tall and wide a vehicle is because everyone knows a fridge is more likely to tip than a sofa," said Eron Shosteck, a spokesman for the Alliance of Automobile Manufacturers, which represents most major auto companies.

"But it fails to take into account such variables as weather, road conditions, driver behavior, whether the driver is drowsy or impaired by drink or drugs," Shosteck said. "It will take a few days to analyze and digest the data and assess whether the new dynamic test provides useful consumer information."

In the dynamic test, a driver operates the vehicle in a straight line at the start of the test and then activates a computer that steers and maintains vehicle speed through the rest of the maneuver to ensure repeatability.

Monitors measure how high wheels lift off the ground in the lane-change maneuvers to predict the likelihood of a rollover. Vehicles are equipped with outriggers to prevent them from rolling.

"This is a single test that can tell us all we need to know," Dr. Jeffrey Runge, NHTSA administrator, said during an announcement at the agency's test facility in East Liberty, Ohio.

As a "consumer information program," the test imposes no regulations on the auto industry. However, NHTSA expects the test will encourage automakers to design and equip vehicles, particularly SUVs, to score well.

"Sooner or later, the test will encourage manufacturers to add stability control," said Brian O'Neill, president of the Insurance Institute for Highway Safety, a research and lobbying group funded by insurers.

Stability control applies the brakes and reduces engine power to prevent vehicles from skidding off the road, where they can be tripped by curbs or grass and roll over. Future SUVs also are likely to be designed with lower centers of gravity to reduce the chances for rollovers.

NHTSA demonstrated the test at its Ohio facility yesterday with two versions of the Toyota 4Runner. The inside wheels of a 2000 model lifted several inches in lane changes at 35 mph, causing the outrigger to scrape the pavement. A 2003 model, redesigned with a lower center of gravity and equipped with stability control, completed the course at 50 mph without lifting its wheels.

Rollover deaths in cars and light trucks grew to a record 10,666 last year, accounting for nearly a third of fatalities in those vehicles. Sixty-one percent of fatalities in SUVs and 45 percent in pickups were from rollovers vs. 22 percent in cars.

The Chicago Tribune is a Tribune Publishing newspaper.

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