SUVs Rank Lowest in NHTSA Rollover Ratings
Seeking to curb demand for vehicles prone to rollover crashes, a leading cause of deaths on U.S. highways, federal auto safety regulators began providing more details on August 9 about the stability of some popular cars and trucks, according to a story in the Detroit News on August 10.Until now, the National Highway Traffic Safety Administration (NHTSA) has provided a five-star rating system that was criticized by safety advocates because it sometimes gave better scores to vehicles that tip during a road test than those that stayed on all four tires. The new government information indicates how likely — on a percentage basis — a vehicle is to roll over in a single-vehicle crash. The agency awards five stars to vehicles that roll over 10 percent of the time or less, and one star to vehicles that roll over between 40 and 50 percent of the time. The new information will also give car buyers a gauge of how well a vehicle stacks up against models in the same class, such as minivans, SUVs, or pickup trucks. Though rollover crashes only represent about 3 percent of accidents, they account for more than 10,000 deaths — a third of annual highway fatalities. Automakers support the agency’s move to provide more consumer information, but caution shoppers not to put too much weight on one measurement. A vehicle’s stability can be influenced by an array of factors, such as height, the width between tires, the design of its suspension system, tire grip, the location of the engine mount, and even the weight of its sunroof, NHTSA engineers say. About 75 percent of passengers who die in a rollover accident also aren’t belted, government data shows.NHTSA uses three sets of tests and information to compute the scores. It uses real-world accident data, a calculation that essentially measures center of gravity, and a dynamic test maneuver whereby a vehicle is quickly turned one way and then sharply the other way. That so-called “fishhook” test, unveiled in October, is supported by safety advocates but they believe NHTSA should give more weight to the test results, particularly whether a vehicle “tipped” or not. To enhance safety of SUVs, which are more prone to roll over, some automakers are already installing electronic stability technology, which senses when a vehicle starts to tip and automatically slows it down. Such systems come standard on several General Motors Corp. vehicles, including the Cadillac Escalade and the GMC Denali, said GM spokesman Chris Preuss. Ford announced last month that it will equip its best-selling Ford Explorer and three other sport utility/vehicles with standard anti-rollover technology, beginning with 2005 models.