U.S. Transportation Secretary Rodney Slater on May 25 proposed a rating program to measure a vehicle’s likelihood to roll over. The program would provide star ratings for rollover performance, the same approach currently used for providing information about performance in frontal and side crashes in the U.S. Department of Transportation’s New Car Assessment Program. The National Highway Traffic Safety Administration (NHTSA) is opening a 60-day comment period to solicit public views on its proposed rollover rating program. Final decision on the rollover rating program, which is set to begin with model-year 2001 vehicles, will be made later this year. Some light trucks, including sport/utility vehicles, are constructed with higher ground clearance, a feature that contributes to a higher rollover rate compared to other vehicle types. After research, NHTSA determined that a vehicle’s “static stability factor” is the most reliable indicator of rollover risk in single-vehicle crashes. The static stability factor of a vehicle is one-half the track width (the distance between two wheels on the same axle) divided by the height of the center of gravity above the road. The announcement met resistence from the Alliance of Automobile Manufacturers. Robert Strassburger, the alliance's vice president, vehicle safety and harmonization, responded with the following statement: "While we fully support efforts to reduce the incidence of rollovers, the Alliance believes that NHTSA's proposed rollover rating is much too simplistic to contribute to this goal. Real-world rollover crashes involve many complex factors-the driver, road conditions, environmental conditions, and vehicle occupants-in addition to vehicle design considerations. In fact, vehicle characteristics are by far the smallest contributing factor in rollover crashes involving injury and death. "The Alliance is surprised that NHTSA proposed this particular measure for rating rollover propensity, since this same measure was rejected by the agency as inappropriate for a safety standard or as a consumer information rating more than 10 years ago. "Automakers are working to minimize the incidence of rollovers, through consumer education and through the development of advanced technologies- especially those designed to warn a driver to modify his or her behavior so as to avoid the conditions that lead to a crash. Manufacturers are also working to reduce the risks from rollovers when they do occur through new occupant protection safety measures."