Evaluation of Occupant Loading in Low- to Moderate-Speed Frontal and Rear-End Motor Vehicle Collisions

Low- to moderate-speed motor vehicle collisions are common roadway occurrences that are generally associated with low rates of reported injury. While such complaints are generally infrequent, claims of injuries resulting from low- to moderate-speed motor vehicle collisions persist. A limited body of literature using quantitative techniques and full-scale crash tests is available to assess the injury potential associated with such collisions. Prior studies have analyzed occupant kinematics and kinetics as well as human injury risk in low- to moderate-speed collisions with older vehicle vintages but do not assess the effects of updated vehicle interior designs and occupant protection devices reflective of efforts to optimize occupant kinematics and reduce occupant loading and injury risk in more modern vehicles. This study was conducted to evaluate the injury potential for occupants of vehicles with modern design elements involved in low- to moderate-speed inline motor vehicle collisions. We expected to find that occupants in modern vehicles would demonstrate low potential for injury in such collisions.

Four full-scale inline (collinear) crash tests were conducted to assess occupant loading during frontal and rear-end impacts. The vehicles used in each test were instrumented late-model, mid-sized sedans of the same make and model occupied by restrained and instrumented Hybrid III 50^th-percentile male anthropomorphic test devices (ATDs). The tests involved aligned front-to-rear bumper collisions at closing speeds ranging from 7.4 kph to 33.6 kph (4.6 mph to 20.9 mph). Kinetic data collected from the instrumented ATDs were evaluated to assess the biomechanical loading environment throughout the crash pulse in both the striking (bullet) and struck (target) vehicles. Evaluation of the occupant responses established that the loads and moments generated during these low- to moderate-speed collisions were far less than accepted injury assessment reference values (IARVs). Furthermore, the recorded spinal loads demonstrated characteristics of inertial loading with similar timescales as common daily activities and, in many cases, were of magnitudes less than or comparable to loads generated by volunteers performing volitional and non-injurious activities.