Safety Group Promotes New Test for Vehicle Roof Crush

December 14, 2006

A national auto safety watchdog group this week unveiled a new test to measure a vehicle’s resistance to roof crush in a rollover, saying it offers a superior method to a current government proposal.

Public Citizen said the dynamic test, developed by two California engineers, assesses whether the vehicle protects someone in a rollover and also measures the effectiveness of seat belts, side air bags and the ability of windows to avoid shattering.

“The test measures roof strength in the most accurate way possible,” said Joan Claybrook, Public Citizen’s president and a former administrator of the National Highway Traffic Safety Administration.

NHTSA last year proposed a new roof crush standard that would require a vehicle’s roof to withstand a force equal to 2.5 times the vehicle’s weight, increasing it from the current requirement of 1.5 times the vehicle’s weight.

A final rule is being considered. Critics have said the proposal is flawed because it could allow roofs to collapse further than current regulations allow and most automakers already meet the proposal.

Rollover crashes killed 10,816 people in 2005, accounting for about one-third of traffic fatalities even though rollovers comprise only a tiny fraction of crashes.

NHTSA estimates that nearly 600 people are killed and more than 800 are seriously injured annually in cases in which a person wearing a seat belt strikes a collapsed roof during a rollover. It estimates the regulation would save 13 to 44 lives a year.

Auto industry officials have questioned whether strengthening roofs would offer more protection, pointing to the large number of people killed in rollovers who were not belted.

Donald Friedman, an engineer who helped develop the test called the Jordan Rollover System, said it would help distinguish between vehicles with safe and unsafe roofs while providing more information on the restraint system.

The new test involves mounting a vehicle on a spit supported by two vertical rails. A piece of roadway is run underneath the vehicle as its rotated and dropped so the roof hits the road. It tests two roof-to-ground contacts.

The current test involves a steel plate being positioned on part of the roof to simulate the roof striking the ground.

NHTSA spokesman Rae Tyson said the agency was actively working on the rule and would consider the opinions of a variety of groups before completing its work. Congress mandated a final roof crush rule by July 2008.

The agency has researched using a dynamic test in the past but found it to be overly severe and difficult to repeat the same conditions every time.

Claybrook said her organization was meeting Wednesday with NHTSA administrator Nicole Nason and would discuss the roof crush proposal with congressional aides.


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