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Low-speed collisions between tractor-semitrailers and passenger vehicles may result in large areas of visible damage to the passenger vehicle, but often produce limited damage to the tractor-semitrailer. Despite this, such accidents may lead to assertions of serious injury to the tractor driver and/or sleeper compartment occupant. Research regarding the impact environment and resulting injury potential of the occupants during these types of impacts is limited. This research investigated driver and sleeper compartment occupant responses to relatively low-speed and low-acceleration impact events. Five crash tests involving impact between a tractor-semitrailer and a passenger car were conducted. The test vehicles were a van semitrailer pulled by a tractor and three identical mid-sized sedans. The occupants of the tractor included a human driver and an un-instrumented Hybrid III 50th-percentile-male anthropomorphic test device (ATD).

Accident investigators are often required to determine if an occupant was wearing their seat belt during a collision. Previous studies have provided examples of physical evidence relied upon by investigators to determine if the seat belt assembly was subjected to occupant restraint loading. This paper examines the potential for clothing fibers to be permanently transferred to the seat belt webbing during a collision. To evaluate fabric transfer evidence as an indicator of restraint usage by an occupant during a collision, the following issues were examined: automotive seat belt webbing construction and behavior under load, fiber evidence found on the webbing in new and used conditions, and the transfer of different types of clothing fibers to webbing during full-scale sled testing.

Previous studies have suggested injury assessment reference values (IARVs) for lower neck injury based on scaled upper neck values. This study developed independent flexion and extension IARVs for the lower neck by matching Anthropomorphic Test Device (ATD) data to impact-tested post-mortem human subjects (PMHSs) with mid- to low-cervical spine injuries. Pendulum and sled tests with Hybrid III midsize male and small female ATDs were run under conditions mimicking those of published PMHS torso drop-sled tests and other PMHS studies. Measurements included upper and lower neck forces and moments, head acceleration, head rotation rate, and head/neck angles for the pendulum tests. Rear impacts corresponding to rigid seatback tests without a head restraint produced lower neck extension moments that increased dramatically with test severity, as measured by increasing delta-V and/or decreasing pulse duration.

Accident investigators are often required to determine if an occupant was using a seat belt during a collision. Substantial research has been conducted on the types of physical evidence generated on a seat belt by occupant loading during a collision. However, very little research has been conducted concerning the characteristics of physical evidence that is created when an occupant uses their seat belt improperly. Case studies with misused seat belts were reviewed showing tell-tales of atypical or improper restraint usage. Occupants also experienced injuries consistent with greater excursion and contact with vehicle interior surfaces. To compare the physical evidence of properly and improperly used restraints, automotive frontal sled tests were conducted with matched pairs of anthropomorphic test devices (ATD) with seat belts used both correctly and incorrectly. When the seat belt was used improperly, distinctly different marks were observed.

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.