Injury Causation in Rollover Accidents and the Biofidelity of Hybrid III Data in Rollover Tests

There is a continuing debate in the scientific literature and among policy making bodies regarding the role of roof crush in the causation of rollover accident injuries. A question arising from field studies is whether the correlation between roof crush and injuries occurs because roof crush causes injuries or because roof crush is associated with accident severity, which is related to injury potential. Recent literature is reviewed to address this question. The Malibu rollover tests have been criticized for the level of “potentially injurious impacts” measured in the Hybrid III dummies used in these studies. Additionally, it has been asserted that the Hybrid III neck is excessively stiff in compression and that experimental testing with the Hybrid III produces results that are not representative of human occupant responses. A careful review of the literature reveals that the Hybrid III and cadavers have similar neck stiffnesses in some loading modes when subjected to the same boundary conditions. The time history of neck forces developed in a drop test using a Hybrid III dummy was compared to the time history of neck forces found in recently published cadaver drop tests and found to be similar. A published computational model proposing a causal relationship between roof stiffness and injury was found to be inaccurate and non-representative of human occupant kinematics. Research to date has found that roof crush is not causally related to injuries in typical rollover accidents.