Double shoulder belts called safer for drivers

WASHINGTON—When it comes to car-wreck protection, the shoulder has been neglected for too long.

That's the word from a NASCAR safety consultant who says the racetrack can teach the highway a lesson about how to walk away from a crash.

"We knew double shoulder belts were probably better, but the race car data says they are really better," John Melvin, an expert on impact injury, told a Society of Automotive Engineers conference Wednesday.

Melvin said that keeping occupants positioned well in a crash with four-point belts—straps over each shoulder and each hip—would become more important as the driving population continued to age.

"If you wear a three-point belt, you get rib injuries before you get to the air bag with the elderly," he said.

Side-impact crashes are among the deadliest on America's highways, killing more than 9,000 people in 2005.

While such crashes are frequent in racing, because cars tend to slam sideways against the walls of the tracks or other vehicles, their outcomes are a lot better.

From 2002 to 2005, NASCAR's three racing series recorded 2,154 side-impact crashes, 560 rear crashes and 211 frontal crashes, Melvin said. The result was one serious head injury, one serious neck injury and some short bouts of unconsciousness and limb injuries. Racers typically wear five-point or even six-point belts, and racing seats hold drivers' bodies much more securely than seats in other cars do.

"Many of these crashes would have been fatal" without advanced protection systems, said Melvin, the president of Tandelta Inc., a biomechanical research and consulting firm.

Although single shoulder belts went a long way in preventing head and chest injuries in passenger cars, occupants still can twist out of them in certain side-impact and rollover crashes.

Melvin said researchers used to think that unsecured shoulders moved out of the way in side-impact crashes. But they can make the torso much more susceptible to injury. Racing shows that stabilizing both shoulders allows them to absorb the crash forces and protect the chest.

The National Highway Traffic Safety Administration has been studying how to improve protection in side-impact crashes for several years.

Ford Motor Co. is in the advanced stages of developing a double shoulder belt, which looks a bit like suspenders because it comes out of the seat back instead of being attached to side pillars.

But Ford still has to figure out how to keep the upper straps from pulling the lap belt too high over the fragile abdomen instead of keeping it low over the bony hips.

"The public has to accept it, too," said Priya Prasad, a technical fellow in safety research at Ford.

Making it past the marketing department could be a big hurdle for automakers.

It took decades for single shoulder belts to become standard in all seating positions in passenger cars, which had only lap belts at first.

Another obstacle is the current design of crash test dummies, which don't have shoulders realistic enough to do scientific testing for advanced belt systems.

Racing provides unique crash-safety research because it records every movement and crash force and removes all the assumptions made in normal accident reconstruction, said Herb Fishel, former executive director of General Motors Corp.'s racing division.

"Racing can be a high-speed test laboratory ... to address major safety issues," said Fishel, a pro racing consultant with the Indy Racing League and the American Lemans Series.


(c) 2007, McClatchy-Tribune Information Services.

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