Occupant Kinematics and Restraint Effectiveness during a Quarter-Turn Rollover in a Heavy Truck 2004-01-0327

The objective of this study was to examine the effectiveness of the typical 3-point restraint system during a quarter-turn rollover of a heavy truck. Five far-side, quarter-turn rollover dynamic tests (3 belted and 2 unbelted tests using a Hybrid II dummy) were conducted using a specially designed large hydraulic machine (causing typical real-world peak angular velocities such as 115° to 140° per second). Four far-side, quarter-turn+ (∼110°) static rollover tests (all belted - one test with a Hybrid II test dummy and the other three with human volunteers) were conducted using a specially designed machine driven by rotational motion from an electric motor (constant roll speed of approximately 6° to 7° per second). A tractor cab and seat and the most commonly used dual-sensitive 3-point belt system were mounted on the test machines. Instrumentation included various transducers, accelerometers, and high speed video cameras to record selected data. As expected, unbelted occupants experienced potential for serious head injuries and possible neck injuries. The shoulder belt was ineffective in these simulated far-side rollover tests (i.e. the upper torso slipped out of the shoulder belt early in the rollover; the ATD's motion was mostly lateral with minimal longitudinal acceleration/deceleration in this study). The lapbelt was effective at keeping the driver's pelvis in the seat. Drivers will stay in their seat while belted although these tests demonstrate that the driver's head will strike the interior headliner or other objects that may be mounted to the headliner (such as a CB radio). HIC values are low for belted headliner strikes (∼50); however the possibility for serious neck injuries may exist and cannot be ruled out for belted occupants from the results in this study. This is especially true due to the observed impact of the vertex of the ATD's head with the headliner. It may be useful to conduct future tests using a Hybrid III ATD to collect direct ATD data with respect to inferences about neck injury.