Industry Braces for Strengthened Car Roofs

After years of debate, the National Highway Traffic Safety Administration has revised the vehicle roof strength rule, Federal Motor Vehicle Safety Standard (FMVSS) No. 216. The new standard will require manufacturers to design vehicle roofs that withstand at least three times the weight of a light-duty vehicle (up to 6,000 lbs.) during a two-sided roof strength test. The current standard, which had remained unchanged since 1971, requires the roof to support at least 1.5 times the vehicle weight when tested on one side only.

The tests are conducted by pressing a metal plate down on the roof over the driver’s seat, then the passenger’s seat. The NHTSA will continue to rely on static tests rather than include a dynamic test to simulate a vehicle rollover.

For the first time, the NHTSA will also apply the rule to heavier vehicles weighing between 6,000 and 10,000 lbs. In this instance, the driver’s and passenger’s side must withstand 1.5 times the weight of the vehicle.

The requirements will be phased in over a four-year period between September 2012 and September 2016. The NHTSA estimates that compliance with the upgraded roof strength standard will increase lifetime consumer costs by $69 to $114 per vehicle.

During the rulemaking process, SEMA cautioned the NHTSA that a tougher standard must still accommodate installation of specialty-equipment sunroofs and other products that interact with the roof. The NHTSA responded that vehicles with sunroofs had been tested under the new requirements and passed and that the agency did not foresee any problems with specialty-equipment installations. For additional information, contact Stuart Gosswein at stuartg@sema.org.