What are the rollover resistance ratings assigned by NHTSA?
Since 2001 the National Highway Traffic Safety Administration (NHTSA) has been assigning rollover resistance ratings to vehicles (one to five stars). These ratings can provide some indication about which specific vehicles are more likely to be involved in rollover crashes. Between 2001 and 2003, the ratings were calculated using SSF only. SSF is calculated by dividing half of a vehicle’s track width (the distance between the right and left tires) by its center of gravity height. Wider vehicles with centers of gravity closer to the ground tend to be more stable, but this measurement does not account for dynamic effects such as those due to a vehicle’s suspension. Beginning in 2004, the rollover resistance rating system was revised to combine the SSF with results from a dynamic handling test, but this test changes the star ratings of only a few vehicles.6 7. How does electronic stability control work? ESC is a vehicle control system comprised of sensors, brakes, engine control modules, a
