Under pressure from consumer groups, the National Highway Traffic and Safety Administration instituted a 5-star rating system for vehicles in 2001. This rating system is based on a vehicles's Static Stability Factor [SSF] and uses a mathematical formula to determine the center of gravity of the vehicle. The higher the center of gravity, the greater the risk for rollover in emergency avoidance maneuvers.
However, the National Academy of Sciences [NAS] came out with a report in February 2002 that concluded that dynamic on-road testing of vehicles was a necessary addition to the SSF system used by NHTSA to evaluate rollover propensity. In October 2003, NHTSA released a dynamic rollover resistance test in each vehicle is loaded with the equivalent of five adult-size passengers and subjected to a reverse-steer driving maneuver designed to provoke a possible tip-up in a severe but real world steering scenario.
In 2004, no sport-utility vehicles won the government's highest safety rating of 5-stars in the round of rollover tests. In the NHTSA released rollover ratings for 14 SUVs from the 2003 model year, while most SUVs received three out of five stars, the Mitsubishi Montero Sport received two-star ratings. |
