Vehicle Roof Strength Found A Link Between Fatalities. A new federal study that could have major implications in the growing debate over vehicle roof strength found a strong link between fatalities and injuries, and the severity of crushed roofs in rollover accidents.
Automakers have contended for years that there’s no solid evidence of a correlation between roof strength and the likelihood of injury and death in rollover accidents.
The new findings, however, could provide crucial supporting evidence for federal officials seeking to strengthen a 33-year-old roof strength standard that many safety advocates say is far too weak to protect U.S. motorists, particularly as rollover-prone SUVs and pickups proliferate.
The National Highway Traffic Safety Administration, which published the study this month, said it plans to propose tougher roof strength requirements by year’s end. The conclusions support earlier NHTSA research that found a link between crushed roofs and deaths.
“We want to make sure what we propose has a basis in reality,” said Rae Tyson, NHTSA spokesman. “This indicates the direction we are contemplating has some scientific research behind it.”
General Motors Corp. spokesman Chris Preuss said company experts would have to review the study before issuing any statement. But Preuss said roof strength was not the most important factor in reducing fatalities in rollover crashes.
“We know unquestionably through statistics that most rollover deaths and injuries occur when unbelted occupants are ejected from the vehicle,” Preuss said. “The seat belt is the first and best safety device in securing the occupant and preventing injury.”
Rollover crashes are one of the leading causes of death on U.S. highways. In newly released data, NHTSA said 10,376 Americans died in rollover crashes in 2003 about one-third of all passenger-vehicle highway deaths.
And each year, an estimated 7,000 people are killed or severely injured in rollovers in which the roof crushed, according to federal statistics.
Automakers are expected to oppose any sweeping changes to the roof-strength requirements for cars and trucks, which could add cost and weight to millions of vehicles.
The companies currently are fighting hundreds of lawsuits in courtrooms around the country arising from rollover accidents, leaving them potentially liable for hundreds of millions of dollars in damages. In June, Ford lost a record $368 million verdict in a San Diego rollover case involving a crushed roof on an Explorer SUV.
NHTSA officials have been reviewing the latest research since early this year. It was published on the Department of Transportation’s Web site earlier this month.
In the new study, NHTSA researchers examined 273 severe rollover crashes between 1997 and 2000. The cases were culled from NHTSA’s National Automotive Sampling System, a cross-section of crashes meant to be statistically representative of all U.S. crashes.
In one important conclusion, NHTSA found there was a clear statistical correlation between the amount a roof intruded into the passenger compartment and the severity of injury. In cases where occupants weren’t injured, the vehicles averaged 16 centimeters of lost headroom due to roof intrusion. In accidents with the most severe injuries, the vehicles lost lost an average of 24 centimeters of headroom in the rollover crashes.
“This just reinforces our view that improvements to the roof-crush standard are necessary,” said Henry Jasny, general counsel for Advocates for Highway and Auto Safety, a Washington safety watchdog group.
In 1971, GM and Ford Motor Co. led an industrywide effort to persuade federal officials to adopt a minimum standard for roof strength but only after their vehicle fleets failed the government’s first proposed test, according to internal corporate documents examined by The Detroit News.
Furthermore, automakers over the years have fought potential upgrades to the roof-strength standard, even while their own European operations build and test stronger roofs.
The new NHTSA study indicates that the agency is leaning toward toughening the roof-strength test, known as Federal Motor Vehicle Safety Standard 216. NHTSA said damage patterns produced by the existing test do not match what its researchers found in real-world crashes. But by increasing the force applied to the test, the agency did produce results similar to those in the crash files.
In the 216 test, one side of the roof must support one and a half times the unloaded weight of the vehicle. For cars, the test applies a maximum of 5,000 pounds of force.
To address the proliferation of bigger trucks and SUVs, NHTSA attempted in 1989 to apply the regulation to vehicles weighing up to 10,000 pounds. But the Big Three lobbied against it and NHTSA gave in, agreeing only to test vehicles that weigh 6,000 pounds or less. In effect, the heaviest trucks and SUVs, mainstream products like the Dodge Durango, Lincoln Navigator and Chevy Tahoe, are technically exempt from the 216 test.
Safety advocates want NHTSA to design a much tougher test, a crash test similar to what vehicles undergo in actual rollovers. NHTSA researchers say they have not been able to devise a crash test that produces the same results every time, a legal requirement for any new safety standard.
Donald Friedman, a former GM engineer and roof strength expert who has testified on behalf of dozens of plaintiffs in product liability cases, said NHTSA should be looking to devise a test that mimics real-world rollovers rather than strengthening the existing test.
NHTSA to push updates
The agency’s findings are important in justifying any call for stronger roofs. Automakers argue that most injuries in accidents where passengers stay in the vehicle during a rollover are caused by occupants flying out of their seats and into the roof. Industry researchers say the government has not proved that stronger roofs would help reduce injuries and fatalities.
But NHTSA’s new study contradicts auto industry-sponsored research that has cast doubt on the safety benefits of stronger roofs.
NHTSA’s Tyson cautioned that improving roof strength alone would prevent only a fraction of rollover fatalities. The agency is expected to combine new requirements in roof strength with requirements for improved safety belts and other ways to reduce head injuries to save more lives.
“There is no regulation that will ever be 100 percent effective,” Tyson said.
NHTSA is expected to issue a proposal for new roof-strength requirements later this year. The proposed regulation will be reviewed by the Department of Transportation and the White House before being made public.
Safety advocates welcomed the study, saying it is another hurdle that the agency must clear before proceeding to its long-anticipated rule-making push.
“This tells us where NHTSA is going,” said Sean Kane, head of Safety Research & Strategies, a Massachusetts firm that has carefully tracked the government’s safety research. “The agency is setting the foundation for its upcoming rule-making.”