NHTSA was originally planning to make the decision in June, but after hearing Senate disapproval over language pre-empting state court lawsuits and with the need for further analysis, Transportation Secretary Mary Peters said there would be a delay.

NHTSA originally proposed an upgrade to the federal motor vehicle safety standard on roof-crush resistance in August 2005.

In January 2008, a Supplemental Notice of Proposed Rulemaking (SNPRM) was issued to gather comments before issuing a final rule.  This proposal was part of a comprehensive plan for reducing the risk of rollover crashes and the risk of injury or death in those crashes. 

The SNPRM asked for comments on a number of related issues and contained the results of various vehicle tests that the administration will consider when developing the final rule.

The proposed rule strengthened current requirements by mandating that roof structures withstand a force 2.5 times the unloaded vehicle weight, and eliminating the limit of 5,000 pound force for passenger cars. 

The proposed rule also would prohibit any roof component from contacting the head of a seated 50th percentile male dummy when the roof is subjected to a force equivalent to 2.5 times the unloaded vehicle weight.

The U.S. Senate Commerce Committee's Subcommittee on Consumer Affairs, Insurance and Automotive Safety held an Oversight Hearing on Passenger Vehicle Roof Strength on June 4.  The purpose of the hearing was to consider the relationship between vehicle roof strength and occupant injury risk and the history of NHTSA's roof strength standard in improving vehicle safety. 

 
The hearing also focused on reviewing the January SNPRM.  The agency's deadline for issuing the final rule was July 1, though questions raised during the hearing ultimately caused an extension of the deadline to October 2008.