WASHINGTON – could prevent nearly 3,500 rollover accidents and save an estimated 106 lives a year if they were required on trucks, a federal safety official said Tuesday.
Nathaniel Beuse, director of crash avoidance standards at the National Highway Traffic Safety Administration, said his estimate was based on tests of the stability systems the agency conducted with researchers from the University of Michigan. The study found almost 4,400 injuries a year could be prevented with the systems.
All new passenger vehicles are required to have stability control systems, but not commercial trucks even though trucks represent a disproportionate share of rollover accidents.
NHTSA hopes to complete studies on the potential benefits of requiring the systems for tractor trailer trucks before the end of the year, Beuse told a hearing of the National Transportation Safety Board.
"It's just a really powerful technology," said Michigan researcher John Woodrooffe, a co-author of the study. "It actually overrides the driver when it thinks he's going too fast even if he has his foot on the (gas) pedal."
Tractor-trailer drivers often have no warning they're about to roll over, Woodrooffe said in an interview.
"A truck driver can be perfectly happy going around a corner thinking everything is OK and suddenly he's over," Woodrooffe said
The safety board is holding a two-day hearing examining whether enough is being done to prevent tank trucks from rolling over. Tank trucks, more than other trucks, are susceptible to rollovers because the weight distribution of the liquid they carry can shift suddenly, causing an imbalance.
Tank trucks represent 6 percent of large trucks, but they account for 31 percent of all fatal commercial truck rollover crashes.
About half the accidents in which trucks hauling tank trailers rolled over because they went around a curve too fast could have been prevented with stability control systems, according to a Battelle Memorial Institute study.
Tank trucks pose a special concern because they often haul hazardous cargo. The hearing was prompted by an accident in Indianapolis last October in which a tractor truck towing a tank loaded with propane ran off a busy interstate where it intersected with a second interstate, struck a guardrail and exploded. The giant fireball could be seen miles away.
The trailer slammed into a bridge abutment, separating the pillar from the bridge. Five people were injured, but no one was killed.
Loads are dispatched on tank trucks more than 100,000 times a day in the U.S. There are, on average, 1,265 cargo tank truck rollovers annually, the Battelle study said.
Stability control systems employ sensors that tell the vehicle's onboard computer when weight is shifting or is about to shift. The computer automatically applies brakes to one or more wheels to compensate until balance is restored.
There are several kinds of stability control systems. It would cost about $1,200 to retrofit an existing tank truck with the most effective and expensive of the systems, a panel of technical experts told the board. The technology adds less than $1,000 to the price of a new truck, they said.
The systems became commercially available about five years ago. Some manufacturers are now including them as standard equipment on new tank trailers.
However, Neil Voorhees, safety director for Trimac Transportation Systems, a national trucking company headquartered in Houston, said trucking companies are buying the systems at a slow rate.
"Until the government steps up in this area, we're missing a golden opportunity," said Voorhees, whose company has been buying the systems. Trimac has seen its rollover accidents drop from 11 a year to one a year thanks to the systems, he said.