A new rollover rating system based on a dynamic driving test may not totally replace the controversial static stability factor (SSF) after all, the National Highway Traffic and Safety Admin. (NHTSA) says. The new “star” system, which will be linked to test scores achieved during a series of maneuvers being developed by NHTSA, might integrate a vehicle's SSF, NHTSA says. Calculated by halving a vehicle's track width divided by the height at its center of gravity, the SSF has come under fire because it fails to factor in mitigating circumstances such as advanced suspension systems. NHTSA is in the midst of developing a dynamic rollover test and soon will call for comments on its proposed methodology. The vehicles being used for testing the various maneuvers are: an '01 Chevrolet Blazer, '01 Ford Escape, '99 Mercedes-Benz ML 320 and an '01 Toyota 4Runner.