EXAMINATION OF ROLLOVER CRASH MECHANISMS AND OCCUPANT OUTCOMES

This research note addresses the following questions: Which are the most prevalent rollover crash attributes? What is the injury outcome for rollover crash occupants? In this review of National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) data over the years 1995 through 2001, rollover crash mechanisms and their related injury patterns are summarized. The tripping mechanism generally inducing rollover was the ground with initial tripping force exerted at the wheels/tires. The trip-over type of rollover was found to be the most prevalent. Most rollovers ended in one or two quarter turns. Slightly more than half of the single vehicle crashes rolled to the left, driver side leading. As the counterpoint, it was noted that the turn-over (untripped) rollover type was the least frequent type of rollover crash. The occupant data were sorted in relation to restraint use and crash configuration. It was noted that among rollover crash occupants, the percentage that were unrestrained was higher than the analogous percentage among planar crashes. Also, unrestrained occupants were at the greatest risk for injury and ejection. Further, MAIS readings for rollover occupants were proportionally higher than those for planar crash occupants. The head and extremities were injured with greatest frequency. It can be concluded that there would have been a larger number of severe injuries were it not for the benefits of safety belt use.