Crashworthiness refers to how well a vehicle protect? people in a crash, and the Insurance Institute for Highway Safety has evaluated aspects of the crashworthiness of six large luxury car models: BMW 5 series, Lexus LS 400, Mercedes E class, Lincoln Continental, lnfiniti 045, and Cadillac Seville. Expensive cars like these are the ones in which state-of-the-art safety designs and technology typically are introduced. The principal component of each vehicle's crashworthiness evaluation is its performance in a 40 mph frontal offset crash test. Among the cars tested, two earn overall evaluations of good and are designated "best picks:" the BMW 5 series and Lexus LS 400. These cars performed well enough in the offset test to overcome poor bumper performance. Lexus bumpers are especially poor. Two other large luxury cars - the Mercedes E class and Lincoln Continental - earn acceptable overall evaluations. The lnfiniti 045 is marginal, and the Cadillac Seville is poor overall. Frontal Crash Testing Today's passenger vehicles are designed to be more crashworthy than they used to be. Still, about 30,000 occupants die in crashes on U.S. roads each year, mostly in frontal crashes. Since the late 1970s, the federal New Car Assessment Program has compared frontal crashworthiness among new passenger vehicles. This program, which involves 35 mph crash tests into a full-width rigid barrier, has been highly successful in providing consumers with comparative crashworthiness information. It also has been a major contributor to the improvements that characterize new passenger vehicles. The very success of the New Car Assessment Program means remaining differences in performance among most new vehicles in full-width tests are small. This doesn't mean important crashworthiness differences no longer exist. They do exist, and additional crash test configurations can highlight these differences. One such test is the frontal offset crash. Full-width and offset tests complement each other. Distributing crash forces across the full width of a vehicle maximizes energy absorption so that the integrity of the occupant compartment, or safety cage, can be maintained well in all but very high-speed crashes. Full-width tests produce high occupant compartment decelerations, so they're especially demanding of restraint systems. In offset tests, only one side of a vehicle's front end, not the full width, hits the barrier so that a smaller area of the structure must manage the crash energy. This means the front end on the struck side crushes more than in a full-width test, and occupant compartment intrusion is more likely. The bottom line is that full-width tests are especially demanding of restraints but less demanding of structure, while the reverse is true in offsets. In the lnstitute's 40 mph offset test, 40 percent of the total width of each vehicle strikes a barrier on the driver side. The barrier's deformable face is made of aluminum honeycomb, which makes the forces in the test similar to those involved in a frontal offset crash between two vehicles of the same weight, each going just less than 40 mph. This means test results can be compared only among vehicles of similar size and weight. Like full-width crash test results, the results of offset tests cannot be used to compare vehicle performance across size and weight classes. (Author/publisher)
Samenvatting