Technical Sessions

Prof. Raphael Grzebieta, University of New South Wales, Australia
Mr David Young, Monash University, Australia
Prof Andrew McIntosh, University of New South Wales, Australia
Dr Micahel Bambach, Department of Civil Engineering, Monash University, Australia
Dr. Bertrand Fréchède, University of New South Wales, Australia
Mr. Thomas Achilles, Monash University, Australia

There is considerable focus internationally on fatalities and injuries to seat belted occupants resulting from rollover crashes. This paper provides a brief summary of an Australian Research Council (ARC) project "Protecting Occupants in Vehicle Rollover Crashes" and the research findings to date. Approximately 1268 of a total of 1627 road fatalities recorded for year 2005 were investigated using the Australian National Coroners Information System (NCIS). There were 742 vehicle occupant fatalities, from which 216 were in a vehicle involved in a rollover crash where around 63% were in cars, 30% in 4WD vehicles, 6% in trucks and the remainder were non-typical road vehicles such as tractors, etc. The analysis has revealed that almost 1 in every three vehicle occupant fatalities (29%) occur where a vehicle has rolled over. This figure is similar to the proportion of US vehicle occupant fatalities that are rollover crash related, i.e. one in every three vehicle occupant deaths can be attributed to a rollover crash mode. Furthermore, the majority of spinal chord paralysis injuries occurring in Australia is also attributed to this crash mode. Yet there still is no government mandated or consumer dynamic rollover test that protects occupants in such crashes. The paper discusses and presents results that are new and unique for seat belted occupants involved in a rollover crash: the injury mechanisms that lead to neck injury; the causal link between serious head and neck injuries and excessive roof crush; and a proposed rollover crashworthiness testing procedure using the Jordan Rollover System (JRS) test rig and how it may be applied by consumers to rate vehicle rollover occupant crashworthiness of Australian vehicles. Three conclusions have so far been drawn from the research. The first is that statistical data clearly indicates that rollover crashes are dangerous events and should now be prioritised as the leading area of crashworthiness research in terms of mitigating injuries occurring to occupants. The second one is the vertical load imparted to the neck of a seat belted occupant inside a vehicle that is rolling over, where the roof strength is weak, is directly related to the amount of lateral roof distortion a vehicle undergoes at the moment of touchdown. The third one is, if the roof is strong, each quarter turn touchdown will slow the rotating vehicle approximately 4 km/h being a consequence directly related to the roof to ground friction coefficient and the movement of the COG vertically and this movement is a non-injurious change in roll rate for a seat belted occupant.