fb tracking

Government’s New Roof Strength Rule Won’t Help Most of Those Killed or Injured in Rollover Crashes

April 11, 2005

Government’s New Roof Strength Rule Won’t Help Most of Those Killed or Injured in Rollover Crashes

NHTSA Poised to Propose New Roof Strength Standard That Will Not Consider Real-World Crash Factors or Save Many Lives

WASHINGTON, D.C. – A pending government rule regarding vehicle roof strength will not adequately protect the public because it won’t take into account the dynamics of rollover crashes, Public Citizen said today.

Deaths and injuries in rollover crashes are usually caused by the roof crushing in on the trailing side in the rollover crash, according to documents released today at a press conference. If a vehicle rolls first onto the driver’s side, for instance, the passenger is far more likely to be killed or injured than the driver.

But the National Highway Traffic Safety Administration’s (NHTSA) upcoming roof strength rule will offer no protection for occupants sitting in the second side of the vehicle to roll over (the trailing side) because the test will measure the strength of just one side of the roof, engineer and consultant Don Friedman explained.

NHTSA is expected to require automakers to apply pressure to one side of the roof to measure the strength of the roof. But that method is inadequate because it doesn’t take into account real world crash factors, such as the fact that windows and windshields often break in the first quarter turn, weakening the roof by a third. By the time the trailing side of the roof hits the ground, the roof has been substantially weakened, and the far-side A-pillar (a supporting beam beside the windshield) collapses, Friedman said. A majority percent of occupants killed in rollover crashes were sitting in the trailing side of the vehicle.

Further, crash tests show a strong link between roof strength and whether an occupant is ejected.

“A good standard would require roofs strong enough to keep windows intact and thereby prevent ejection,” Friedman said. “From such a standard, we could expect to reduce ejections by at least 50 percent and significantly reduce roof intrusion, preventing 200 deaths and serious injuries every week.”

Every year, 10,400 people are killed and another 17,000 are seriously injured in rollover crashes.

Between 6,000 to 7,000 deaths a year are related to roof collapse and roof crush. The current roof crush standard was enacted in 1971 and took effect in 1973. It has not been updated since.

“The government has a golden opportunity to save lives that are lost in rollover crashes, but all indications are that officials are going to blow it,” said Public Citizen President Joan Claybrook, who was NHTSA administrator from 1977 to 1981. “The only way to determine if a vehicle’s roof will hold up in a rollover crash is to test it under real-world crash conditions. Strong roofs save lives, and weak roofs kill. NHTSA should not have waited 30 years to implement a weak test that ignores what happens when vehicles roll over.”

Friedman pointed to two major problems with NHTSA’s likely roof crush test. First, as noted, the test ignores the trailing side impact in rollover crashes. The second is that the test permits vehicles to have extremely weak A-pillars, which are essential to protecting occupants’ heads and necks. SUVs and pickups roll at a more severe pitch angle than the test applies, putting more force on the A-pillars than the test accounts for.

Further, in an actual rollover, the person’s head falls farther forward and closer to the A-pillar than NHTSA’s test dummy does. Finally, the NHTSA test does not measure the speed of the roof collapse, which can exceed 22 miles per hour. The speed at which a roof collapses is related to the severity of injuries.

Also on Monday, Public Citizen released a compendium of industry documents dating to the 1960s showing that General Motors’ own tests demonstrated a clear link between roof crush and injury. When GM tested the second side of vehicles’ roofs in 1970, the second side of the roofs on six of seven vehicles failed. And a 1982 GM study agreed that ejection, window breakage and roof strength were related. Yet NHTSA rulemaking documents ignore ejection risks when calculating the benefits of a roof strength standard.

The documents are also important because the auto industry for years has maintained that roof strength is unrelated to injuries in rollover. Industry officials claim that people sustain head and neck injuries when they “dive” (are thrown) into the roofs of their vehicles, not when the roofs crush into the people’s heads. The documents bolster findings in a report released last month by Public Citizen showing that automakers have misled government regulators and the public for years by claiming that roof strength and injuries in rollover crashes are unrelated.

The current roof crush standard calls for a one-sided static test (not a simulated real-world [dynamic] crash test) that requires one section of a vehicle’s roof to withstand 1.5 times the vehicle’s weight. It is expected that the agency’s new rule will essentially be the same, except that it will require a roof to withstand 2.5 times the vehicle’s weight before contacting the head of a seated dummy. The agency has indicated that its new rule will save only 50 lives – a fraction of the lives currently lost in roof crush-related rollover crashes.

In addition to preventing roofs from crushing in, padding and adequate restraint systems – such as side head air bags, safety glass in side windows and pre-tensioned belts – are key to making rollover crashes survivable. To access the documents released today, click here.