ARLINGTON, VA --- The Insurance Institute for Highway Safety said last week it will begin requiring that vehicle models have stronger roofs in order to qualify for the group's coveted "Top Safety Pick" rating, the Detroit News reported.

Adrian Lund, president of IIHS, said it was time to require automakers to do more to improve roof strength to reduce injuries and deaths suffered in rollovers. He cited a new IIHS study that concludes a 1.0 increase in roof strength reduces the risk of fatalities in a single-passenger car rollover by just over 20 percent.

In January, the National Highway Traffic Safety Administration released a proposal to require a vehicle roof to withstand a force equal to 2.5 times the vehicle weight while at the same time providing enough head room for a buckled-in, average-size adult male to avoid being struck. That's a jump from the current standard of withstanding a force equal to 1.5 times the vehicle weight. NHTSA hasn't finalized its regulation, however.

Lund said starting in the fall, IIHS will require a vehicle to have a 4.0 rating to qualify for a Top Safety Pick designation.

"We see significant safety benefits in stronger vehicle roofs," Lund said. "The government is moving slowly and they are going to continue to move slowly."

He said NHTSA has "clearly undercounted" the number of injuries and deaths that can be prevented by stronger roofs.

The Alliance of Automobile Manufacturers, the trade group that represents Detroit's Big Three automakers, Toyota Motor Corp., Daimler AG and six others, supports increasing the standard to 2.5 times the vehicle's weight, but says going beyond that isn't necessary.

In December, the Bush Administration abandoned efforts to comply with a congressional deadline to update the standard. It was the third delay in finalizing the standards and Transportation Secretary Mary Peters said the new rule would be in place by April 30, the Detroit News reported.