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Light truck and SUV rollovers often involve ground contacts at the roof rails or door sills that can induce significant vertical shear loads at the latch/striker interface. These vertical loads are not evaluated in Federal Motor Vehicle Safety Standard testing yet they are known to cause latch failures. Such failures expose both belted and unrestrained occupants to increased injury risk. An example of two such failures can be found in open literature in a single van rollover test. A simple vertical load test for latches is described by the authors and evaluated for discrimination, suitability and repeatability. This test was applied to an array of current and past generation latches found on many popular SUVs and light trucks. A large range of failure loads was encountered. A review of the structural features of the superior performing test samples suggests simple modifications that could dramatically improve performance of the remaining latches.

Automotive manufacturers often rely upon features such as automatic locking to enhance the security and crashworthiness of doors in rollover accidents. This can be verified in warnings conveyed to vehicle owners through some owner's manuals. At the present time, there are no requirements on the dynamic performance of door locking systems within the Federal Motor Vehicle Safety Standards (FMVSS), although some static inertia requirements exist for latch systems. Field accident investigation and laboratory testing has revealed that some locked doors can self-unlock in rollover accidents when a vehicle sustains a roof impact. Using standard laboratory shock testing machinery, the acceleration boundaries required to trigger self-unlocking have been mapped for some sample doors. Impact pulses of surprisingly low levels of acceleration, when combined with sufficient duration have been found to trigger this response.