Roof-crush standards

Government to require stronger vehicle roofs

Last updated: April 2012

If a government proposal is passed into law, cars and trucks will be required to have stronger roofs to protect occupants in rollover accidents. This could represent a significant safety improvement, especially for SUVs and pickups, which are statistically more likely to roll over than passenger cars. But some safety advocates say the proposal doesn't go far enough. Another concern: Part of the proposal may limit consumer lawsuits against automakers.

Rollover accidents aren't frequent—they occur in only about 3 percent of serious crashes—but they are deadly, involved in about 33 percent of all vehicle-occupant deaths. In the U.S., approximately 10,000 people die each year in rollover accidents and 24,000 are severely injured.

A key factor in how well a vehicle can protect you in a rollover is the strength of its roof. The National Highway Traffic Safety Administration currently conducts roof-crush tests by pressing down on a plate placed against the edge of a vehicle's roof. The roof has to withstand a force equivalent to 1.5 times the weight of the vehicle, up to a limit of 5,000 pounds, without the plate moving more than 5 inches.

A revised regulation enacted in 2009 requires vehicle roofs to withstand 3 times the vehicle's weight in that test. Under that force, the roof should not bend so far that it would touch the head of a median-height-male test dummy. How far the roof could crush without touching the head of the dummy would depend on the dimensions of the vehicle. It also requires, for the first time, that vehicles over 6,000 pounds meet a roof-crush standard, although the standard for the heaviest passenger vehicles will remain at 1.5 times the vehicle's weight.

The revised roof-crush standard starts phasing with the 2012 model year and applies to all new vehicles by the 2017 model year.

A step in the right direction, but not far enough

We believe that raising the weight that the roof must withstand and including heavier passenger vehicles were steps in the right direction. But the final regulation should have gone further, to better reflect real-world rollovers.

For instance, the plate pressing on the roof should be angled farther forward to better simulate real-world rollovers. Second, the standard should specify 4 times the vehicle's weight instead of 3 times. Third, every passenger vehicle, including the heaviest ones, ought to be subject to the same rigorous roof-strength standard.

Limits on lawsuits

Perhaps the most worrisome part of the proposal, however, is language that may limit lawsuits against automakers. Under the new rule, injured occupants can't make a legal claim that automakers had any obligation to make roofs stronger than the standard requires, even where state courts had previously held manufacturers to a stricter standard. We believe that gives automakers less incentive to build roofs as strong as they are able to.

The government, however, dismisses that concern. The Executive Summary to the final rule sates, “We do not foresee any potential State tort requirements that might conflict with today's final rule. Without any conflict, there could not be any implied preemption.”

The full proposal is online at www.nhtsa.dot.gov/cars/rules/rulings/RoofCrushNotice/216NPRM-to-FR.html.