Roof strength is one of many factors that determine whether people inside a vehicle survive rollover accidents, according to a report published by the Insurance Institute for Highway Safety.
By testing the roofs of 11 sport utility vehicles, then looking at the deaths and injury rates in accidents, the institute found that the stronger the roof was, the less likelihood of injury or death.
"Roofs that crush too easily are allowing people to be injured and killed," said Adrian Lund, president of the institute. Lund said that stronger roofs would help offer better protection to both unbelted and belted passengers and drivers.
Rollovers account for about one-quarter of those who die in car crashes, but SUVs that are higher off the ground than other vehicles are particularly prone to rollovers. The study contends that stronger roofs, like the one on the 2000 Nissan Xterra, could cut injury risk by a third in single-vehicle SUV rollover crashes.
But not everyone agrees with the report's findings. The Alliance of Automobile Manufacturers called the institute's study "flawed analysis," contending that, "there remains no definitive answer as to what effect roof strength has on injury risk in rollover crashes."
Automakers have voluntarily implemented safety measures like electronic stability control and advanced safety belt systems to boost vehicle safety, and have also started developing sensors that will trigger side curtain air bags during a rollover.
"Automakers understand that the most effective strategy for reducing rollover fatalities and injuries is avoiding a crash in the first place," the alliance said in a statement.
The report comes as the National Highway Traffic Safety Administration updates its standard for passenger vehicles' minimum roof strength.
The current standard requires vehicles to withstand 1½ times the weight of the vehicle before crushing five inches. The administration would like to require passenger vehicles to withstand 2½ times its weight instead. The Insurance Institute for Highway Safety says that's still not good enough, and argues a passenger vehicle should be able to withstand three times its weight when it rolls over.
All of the SUVs tested meet the current government requirements, but some were nearly twice as strong as they need to be. The Alliance for Automobile Manufacturers said the new report should not help shape the administration's decisions regarding the standards for roof strength.
Among the SUVs that performed the worst in the test were the 1996-2001 Ford Explorer, the 1996-2004 Chevrolet Blazer and the 1999-2004 Jeep Grand Cherokee.
"Some automakers are doing better and I applaud them for doing that," said Joan Claybrook, president of Public Citizen and a former administrator of the National Highway Traffic Safety Administration. "But that doesn't mean that you shouldn't have a minimum federal standard that is as high as the best the automakers can do."
For mroe information visit: http://www.iihs.org/sr/pdfs/sr4302.pdf