Rollover accidents continue to cause a large number of serious and fatal injuries. This chapter, from a comprehensive text on vehicle and occupant responses in rollovers, reports on an investigation of restraint function on male and female occupants in rollover events. The study investigated factors influencing neck loading in rollover events in a series of spit tests where vehicles were inverted. Drivers included both male and female volunteers, as well as seated standard and standing pedestrian 50th percentile anthropomorphic dummies. The variables investigated during the spit tests included body shape, pre-roll body position, and vertical seat velocity. Results showed that early in the far-side rolls, the belt tested to slip off the shoulder and the slack was immediately passed through to the lap belt, increasing body excursion toward the roof. An alert position (sitting more upright prior to the roll) increased the body excursion in the roll and the risk of neck injury. Chest geometry and compressibility caused some women to experience excessive motion toward the roof, increasing their risk of neck injury. The authors note that neither dummy adequately simulated the excursions experienced by the live volunteers; the dummy motion toward the roof is much less than that of the human volunteers. The authors also performed computer simulations using the MADYMO occupant, to study the dynamic interaction of the head, torso, and roof during contact with the ground. The authors conclude that a cinching latch plate would better control an occupant's motion toward the roof and thus help prevent cervical spine injury.