Passenger Vehicle Occupant Response to Low-Speed Impacts with a Tractor-Semitrailer 2011-01-1125

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 5^th -percentile-male anthropomorphic test device (ATD) in the driver's seat and an un-instrumented Hybrid III 5^th -percentile-female ATD in the left rear seat. The ATDs were positioned in the vehicle consistent with Federal Motor Vehicle Safety Standard (FMVSS) Number 208, Occupant Crash Protection. The ATD in the driver's seat was restrained with a lap and shoulder belt, while the rear passenger ATD was unrestrained. Instrumentation on the sedans included accelerometers and rotational rate sensors, and occupant kinematics were recorded using onboard and off-board high-speed video cameras. The tests included four sideswipe impacts, involving extended contact between the semitrailer bottom rail (lower longitudinal structure of the trailer box) and dual wheels and the side of the sedans. A single perpendicular collision involving the semitrailer dual wheels and the right front corner of the sedan was also conducted. The driver ATD's head accelerations, upper and lower neck forces and moments, lumbar spine forces and moments, and left and right femur loads were measured, along with seat belt webbing loads. Head and spine data were compared to volunteer studies of vigorous activities of daily living, published human tolerance levels, and Injury Assessment Reference Values (IARVs) used in compliance testing of passenger vehicles. It was determined that the biomechanical responses in the head, upper neck, and femur of the ATD were well below the established IARVs, and the biomechanical responses in the head, upper neck, and lower back of the ATD were lower than or comparable to the responses of these body regions to the loads experienced by volunteers during non-injurious activities.