After taking no action for more than a year, automakers are now working to develop tests for technology that could save thousands of the lives lost in vehicle rollover crashes.
Federal regulators are concerned that the inflatable curtains automakers are installing for protection in side-impact crashes often don't deploy in rollover crashes.
Some vehicles do include rollover sensors that can detect when they are about to tip and trigger the curtains, which help prevent people from being ejected. More than half the nearly 10,000 people killed each year in rollover crashes are completely ejected from their vehicles.
Preventing rollover deaths is a top priority for the National Highway Traffic Safety Administration.
Car company officials working on the issue through the Alliance of Automobile Manufacturers last year could not agree to install the sensors on their vehicles. Under pressure from regulators, an alliance group is now meeting regularly to develop a test that would encourage wider installation of the devices, especially on sport-utility vehicles. The group will meet with NHTSA officials by February to discuss their research, says alliance spokesman Eron Shosteck.
Side curtains typically inflate when vehicles are hit in the side. But they don't always activate in a rollover unless the vehicles have rollover sensors or are hit in the side before they tip over.
"To protect people in rollovers, you've got to keep them inside of the vehicles," says Brian O'Neill, president of the Insurance Institute for Highway Safety. "You need curtains that stay deployed."
Side curtains usually stay inflated at least four seconds, even though most side-impact crashes last only milliseconds, says Manley Ford, a spokesman for auto supplier TRW. But if a vehicle is rolling over, it's important that the bag deploy and stay inflated for at least six seconds in case the vehicle continues to roll.
Automakers, including Toyota and Ford, have installed sensors to deploy side curtains when vehicles begin to roll over. But the technology is often optional. Some brands, including Mitsubishi and BMW, don't offer rollover-triggered side curtains. And it can be difficult to figure out which vehicles have the technology, because they often aren't identified as having anything other than side curtains.
Shosteck says the alliance's technical working group on rollover ejections was "reactivated" in September. The group is trying to come up with test procedures for rollover sensors that would determine when they should deploy curtains.
Still, technical issues remain. If the bags don't deploy fast enough, they can actually force a person's head out the window, causing more injury. And the sensors need to distinguish between a tipping vehicle and one that is being driven purposely off-road before triggering the curtains.
"Rollovers are slow events compared to frontal and side impacts," says TRW Vice President Doug Campbell. "They are very slow and very unpredictable."