NHTSA in for a Fight Over 'Roof-Crush Rule'

The documents show how Volvo made its XC90 model roofs stronger than the norm by designing a "steel cage" to protect occupants in rollovers. They came up in a trial in Jacksonville, Fla., last spring in which a jury awarded $10.2 million to the family of Claire Duncan , a 26-year-old engineer. The jury found the roof in a Ford Explorer to be defective. Ford is appealing.

The papers include e-mail traffic between the two companies in which Ford tells its subsidiary that it must cease its emphasis on roof strength and get in step with Ford's position on the issue.

The documents were then placed in the NHTSA rulemaking docket. But the agency removed them after Volvo said they were under a protective court order.

Last Thursday, Public Citizen petitioned the Florida state court to make the papers public, claiming they are directly relevant to the current rulemaking. Ford, in a statement, said the documents should be kept from the public because they contain trade secrets.

This twist in the process isn't likely to change much about the final rule, especially since the auto industry says it can meet it easily.

In fact, safety groups also complain that the test for meeting the standard is too weak. NHTSA's proposal includes a test that uses a steel plate or "arm" to crush the roof on one side of the vehicle. The amount of intrusion into passenger space is then calculated. Safety advocates want a test that would replicate the multiple flips that happen in a rollover, which the agency rejected.

Manufacturers stress that other NHTSA rulemakings would better enhance occupant safety, such as side air bags to keep passengers from being ejected from vehicles and requiring stability control systems to keep the vehicle on the road.

"The thing that is getting lost in the weeds is you have to look at all the various initiatives the agency has," said Robert Strassburger , vice president for safety and harmonization for the Alliance for Automobile Manufacturers . "The roof-crush rule will be more of a backstop than anything else."