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Changes in design are reducing whiplash

October 23, 2002|John O'Dell | Times Staff Writer

New car seat and head restraint designs such as those used by Saab and some General Motors brands are dramatically reducing the frequency and severity of neck injuries caused by rear-end crashes, insurance industry researchers say.

A study of accident data by the Insurance Institute for Highway Safety shows that occupants of cars equipped with the most effective of the new head restraint and seat designs are injured about half as often as occupants of the same models of cars with older-style head restraints.

The industry-funded institute says its study is the first to compare performance of old- and new-style head restraints using actual crash report data.

The key to reducing whiplash injury in rear-end crashes is to keep the vehicle occupants' heads and bodies moving in the same direction.

New seats and head restraints are being engineered to reduce so-called differential motion when the force of a rear crash snaps the head one way, while the torso moves the opposite way.

Some of the new designs reviewed by the institute use a fixed system that places the head restraint higher and closer to the backs of occupants' heads for better cushioning in the event a car is hit from the rear.

Another system, by Saab, has active head restraints in which a mechanism pushes the restraint up and toward the back of the head as the occupant's torso sinks into the seat during a rear-end crash.

Some General Motors and Nissan models use the same system, the institute says.

A third type of system studied is used by Volvo and Toyota. The companies' engineers designed seat backs that yield in rear-end crashes to reduce forward acceleration of occupants' torsos.

The institute lauded Volvo for including well-designed and well-located head restraints with its seats, but said one of the three Toyota models studied did not have a well-placed headrest.

A trio of major insurance companies -- Nationwide, Progressive and State Farm -- supplied the data, which cover 2,641 claims. The study looked at injury data in same-model cars with and without the new systems: Ford Taurus and Mercury Sable models were the test models for fixed restraints; Volvo S70s and various Toyota and Lexus models for seat-back systems; and Saab, GM and Nissan models for active restraints.

"There's evidence that many of the new designs are working. In some cases, the reductions in insurance claims for neck injuries are dramatic," said Adrian Lund, chief operating officer for the Insurance Institute and an author of the research report.

The study found a 43% reduction in neck injury claim rates for the Saab, General Motors and Nissan models with active head restraints, compared with rates for accidents involving similar cars built before the restraints were introduced.

Volvos and Fords with new systems also yielded claim reductions, but there weren't enough models in the study to make the findings meaningful, Lund said.

Toyota results also suffered from lack of data, Lund said.

The study actually found a slight increase in injury claims for Toyota and Lexus models with the company's new system, but Lund said that the institute is working with Toyota "to get a better understanding of the results" and to see if newer designs will result in fewer claims.


John O'Dell writes about the automobile industry for Highway 1 and the Business section. E-mail:

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