ROLLOVER CRASH SENSING AND SAFETY OVERVIEW. IN: OCCUPANT AND VEHICLE RESPONSES IN ROLLOVERS

Rollovers account for 10.5% of the first harmful events in fatal crashes and 19.5% of vehicles in fatal crashes had a rollover in the impact sequence. This overview chapter on rollover crash sensing and safety serves as the introduction to a comprehensive textbook on occupant and vehicle responses in rollovers. In this chapter, the authors provide an overview of rollover crash safety, including field crash statistics, pre- and rollover dynamics, test procedures, and dummy responses. The chapter also describes a research program aimed at defining rollover sensing requirements to activate belt pretensioners, roof-rail airbags, and convertible pop-up rollbars. The work required an understanding of the most relevant conditions for field rollovers, vehicle responses, and occupant kinematics in the vehicle. The most common rollovers involve a soil trip, fall-over, and curb trip. The researchers used cross-plots of vehicle roll rate and angle to consider triggering requirements for safety systems and to determine the timing of occupant motion in the vehicle. Results show that some rollovers require triggering of safety systems when the vehicle has only a 10-20 deg. roll angle because roll angular velocities exceed 100 deg./sec. The authors also include a bibliography of relevant literature.