Friday, 31 August 2007 10:00

Luxury Car Safety Performance In Side Impacts

Written by Autobody News staff
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Three of six large car models earn the top rating of good, but one is marginal in side impact crash tests conducted by the Insurance Institute for Highway Safety. Results show a range of performance in how well large cars are designed to protect people in serious side crashes.

        The best performers are the Acura RL, Kia Amanti, and Volvo S80, all 2007 models. The S80 also earns the Institute’s 2007 Top Safety Pick award for superior overall crash protection. The S80 qualifies because it’s rated good in the Institute’s front, side, and rear tests and has electronic stability control as standard equipment.

        The 2007 Cadillac STS and Mercedes E class earn acceptable ratings in the latest round of side tests. The worst performer is the 2008 BMW 5 series, which earns the second lowest rating of marginal for side impact protection. All six cars are equipped with standard side air bags that protect the heads of people in front and rear seats.

        Side impacts are the second most common fatal crash type after frontal crashes. About 9,200 people in passenger vehicles were killed in side impacts in 2005. In crashes with other passenger vehicles during 2004-05, 49 percent of driver deaths in 1-3-year-old cars and minivans occurred in side impacts, up from 31 percent in 1980-81. During the same time, the proportion of driver deaths in frontal crashes declined from 61 to 46 percent.

        “These changes are attributable to two effects,” saids Institute president Adrian Lund. “There have been significant improvements in frontal crash protection – standard air bags, improved structural designs, and increased use of safety belts, for example. At the same time, growing sales of SUVs and pickups have exacerbated height mismatches among passenger vehicles, thereby increasing the risks to occupants of many vehicles struck in the side.”

Price offers no guarantee

The lowest priced vehicle in the group the Institute recently tested, the Amanti, was one of the best performers. One of the most expensive models, the 5 series, was the worst.

        “The Amanti shows that you don’t have to buy an expensive car to get good protection in crashes with SUVs and pickup trucks,” Lund pointed out. The side structure of the Amanti allowed more intrusion than in the other cars in this group, but all of the injury measures recorded on the dummies were low. The standard head curtain air bags for front- and back-seat occupants kept the dummies’ heads from hitting any hard structures including the intruding crash test barrier.

        The head-protecting air bags in the BMW 5 series are tubular structures that differ from the curtain air bags in the Amanti but also are effective. However, torso protection is rated poor for the driver dummy in the 5 series, even though it has separate air bags designed to protect the chests and abdomens of front-seat occupants. Measures recorded on the driver dummy indicate that rib fractures and internal organ injuries would be likely to occur in a real-world crash of this severity. A pelvic fracture also would be possible.

Improvement in occupant protection

The Mercedes E class was re-engineered for 2007 with an emphasis on improving occupant protection in side crashes. When the Institute tested an early production model in 2007, the car earned an acceptable rating mainly because of high forces recorded on the driver dummy’s torso. Mercedes changed the front door trim panels on cars built after May 2007 to try to fix the problem and asked the Institute to test the revised car.

        The result was a slight improvement but not enough to change this car’s rating. The test of the revised design still showed high forces on the driver dummy that could result in rib and pelvic fractures in a real-world crash of similar severity.

        “The E class earns the Institute’s top rating of good for front and rear crash protection. If this manufacturer can improve side impact protection, this car will earn Top Safety Pick,” Lund said.

        General Motors made changes to the Cadillac STS including reinforcing the B-pillars, changing front door trim panels, and modifying the side torso air bags. The car with these changes earns the second highest rating of acceptable.

        Ratings of good, acceptable, marginal, or poor are based on a crash test in which a barrier designed to replicate the front end of a typical SUV or pickup truck strikes the tested vehicle in the side at 31 mph.