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Detailed investigations continually demonstrate that vehicle collision environments are extremely unlikely to produce accelerations of sufficient magnitude and duration to cause inertial release of seat belt buckles. Recently, it has been proposed that the dynamic response of an end-release buckle mounted to the vehicle structure via a metal strap or wire rope can amplify acceleration levels experienced at the floor of the vehicle by a factor of 10 or more, to levels that are high enough to cause inertial release. Experiments and modeling presented here confirm that accelerations may be amplified from the floor of the vehicle to the seat belt buckle, but not by more than a factor of 1.3, and only for acceleration pulse durations that are very short. Shock table testing of end-release seat belt buckles shows that, even with amplification, the resulting buckle accelerations are far below those required to cause inertial release, even at very low webbing tension.

Low-speed sideswipe collisions between tractor-semitrailers and passenger vehicles may result in large areas of visible damage to the passenger vehicle. However, due to the extended contact that occurs during these impacts, it is typical in these incidents for the crash pulse duration to be long and the vehicle accelerations to be correspondingly low. Research regarding the impact environment and resulting injury potential of the occupants during these types of impacts is limited. Five full-scale crash tests utilizing a tractor-semitrailer and a passenger car were conducted to explore the occupant responses during these types of collisions. The test vehicles included a van semitrailer pulled by a tractor and three identical mid-sized sedans. The occupants of the sedans included an instrumented Hybrid III 5th -percentile-male anthropomorphic test device (ATD) in the driver's seat and an un-instrumented Hybrid III 5th -percentile-female ATD in the left rear seat.