Occupant Kinematics and Injury Mechanisms During Rollover in a High Strength-to-Weight Ratio Vehicle

Rollover events involving multiple revolutions are dynamic, high-energy, chaotic events that may result in occupant injury. As such, there is ongoing discussion regarding methods that may reduce injury potential during rollovers. It has been suggested that increasing a vehicle's roof strength will mitigate injury potential. However, numerous experimental studies and published field accident data analyses have failed to show a causal relationship between roof deformation and occupant injury. The current study examines occupant kinematics and injury mechanisms during dolly rollover testing of a vehicle with a high roof strength-to-weight ratio (SWR = 4.8). String potentiometers and high-speed video cameras were used to capture and quantify the dynamic roof motion throughout the rollover. Instrumented Anthropomorphic Test Devices (ATDs) in the front occupant positions allowed for the assessment of occupant kinematics, loading, and injury mechanics during the rollover event. The quantification of the roof motion over the complete time course of the rollover combined with ATD neck loads demonstrated that neck loads in excess of the relevant Injury Assessment Reference Value (IARV) occurred as a result of the dynamic rollover circumstances independent of the vehicle roof motion. Injurious neck loads were observed with relatively small amounts of roof deformation, while relatively small neck loads were observed during large elastic and plastic roof deformations. The results of this testing are discussed in the context of other experimental and field accident data studies examining roof deformation and occupant injury.