NHTSA roof rule comes under attack


Critics: Agency uses wrong method to test strength

By Harry Stoffer
Automotive News / September 05, 2005

A roof over your headNHTSA's proposed roof-strength rule would make these major changes.

  • Raise maximum pressure in roof-crush test by 67%
  • Include heavier vehicles
  • Pre-empt lawsuits
    Source: National Highway Traffic Safety Administration

WASHINGTON -- Retired engineer William Chu offers this response to the government's plan to strengthen vehicle roofs against collapse in rollover crashes: "Not only does it not do the job, it probably makes it worse."

Chu, 67, is familiar with so-called roof crush. As a young engineer at the National Highway Traffic Safety Administration, he says, he helped write the 1971 roof-strength rule that the new proposal would update.

In the judgment of Chu and other critics, NHTSA is using the wrong method to test roof strength. Its proposal won't do enough to protect vehicle occupants, they argue.

NHTSA is expected to consider scores of comments from automakers, safety advocates and trial lawyers before it adopts a final rule in 2006.

More weight on top

NHTSA wants to modify the traditional test for roof crush: pressing a metal plate on the roof over the driver's seat.

The current rule says a roof must withstand pressure equal to 1.5 times the vehicle's weight. The proposal would raise the standard to 2.5 times.

The NHTSA plan would apply the roof-strength standard to vehicles of as much as 10,000 pounds gross vehicle weight. The current limit is 6,000 pounds.

The agency calculates that automakers would need to spend less than $11 a vehicle to bring into compliance cars and trucks that don't already meet the tougher standard. The added cost mostly would be for more metal in roof pillars.

NHTSA estimates the new rule would prevent 44 deaths a year when it takes full effect. About 10,000 Americans die each year in crashes that include rollovers.

NHTSA officials call the roof-strength proposal part of a comprehensive plan to reduce rollover deaths and injuries. The plan includes efforts to keep vehicles from rolling. It also is designed to keep occupants from being thrown through windows and doors if vehicles do roll.

NHTSA says it considered other methods of testing roof strength. Proposals such as a rollover simulation favored by safety groups proved unworkable, the agency says.

Range of views

Joan Claybrook, president of the consumer group Public Citizen, calls the proposal a missed opportunity. She says the new rule is "tragically short of what is needed."

The Alliance of Automobile Manufacturers says it is reviewing the proposal and will submit comments to NHTSA.

Adrian Lund, COO of the Insurance Institute for Highway Safety, says the proposal includes good concepts.

But Lund says it probably won't require much of automakers. He predicts it will have a limited impact at best on safety.

The plan provides that a vehicle that meets the new standard cannot be judged defective by a state law or court decision.

Critics call that language an effort to insulate automakers from the growing number of lawsuits over collapsed roofs.

Sean Kane, president of Safety Research & Strategies Inc., a consulting firm in Rehoboth, Mass., says the pre-emption language would make the new federal standard both a floor and a ceiling. As a result, Kane says, it would remove the industry's incentive to exceed the standard.