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In 2008, Hovey et al. [1] published a mathematical analysis that, for the first time, incorporated yaw data into the trajectory analysis, yielding occupant ejection results that are three-dimensional. We extend on that work to investigate the ability of the mathematical model to predict outcomes of the Ford Expedition dolly rollover test, details of which have been published in Carter et al. [2], Exponent [3], and Luepke et al. [4]. This research validates our occupant trajectory model with the Expedition dolly rollover experimental test data. Previous research had modeled the Expedition rollover test as a two-dimensional, straight-line, roll-only configuration, assuming yaw effects were negligible [17]. We incorporated the longitudinal and lateral components of the vehicle trajectory, eliminating the straight-line limitation. Moreover, we included yaw in addition to roll. Both enhancements resulted in a higher fidelity occupant ejection description.

Advanced glazing has been investigated as a means by which to reduce occupant ejection in rollover accidents. However, most testing on these advanced glazing materials has not effectively captured the occupant kinematics typically seen in actual rollover accidents, and as a result, passing these tests does not ensure occupant retention. While current work has attempted to characterize the dynamic (impact) and static (push-out) material properties necessary for understanding the containment performance of advanced glazing, most testing has consisted of single impacts. Rollover accidents typically include multiple impacts and potentially long duration centrifugal forces on the side glazing. As such, there is little test and/or simulation data to support the theory that advanced glazing would substantially reduce the risk of occupant ejection in rollover accidents.

Occupant ejection may occur during planar and rollover collisions. These ejections can be associated with serious/fatal injuries. Occasionally, occupants will allege that they were wearing a seatbelt immediately before the ejection occurred. Some accident investigators have opined that a seatbelt became disengaged due to collision forces and/or occupant interactions, leaving the occupant essentially unrestrained and exposed to ejection from the vehicle. We present three case studies of collisions with documented seatbelt disengagement at or during the collision, as well as three controlled tests. The release of the seatbelt was always associated with dire consequences for the occupant's outboard upper extremity. Evidence of seatbelt webbing interaction with the occupant was always evident, and the interaction of the belt with the vehicle interior trim was also apparent.