Certain US 4WD utility vehicles now require labelling indicating risk of rollover. This labelling followed field observations that 4WD vehicles were much more likely to fall over. Quite a few of these vehicles had a narrow wheel track and high centre of gravity. From this and associated litigation we have observed a fairly quick widening of wheel base on imported 4WD vehicles, however windscreen labelling on Australian 4WD vehicles is not required, and we have no assessments of their overall rollover propensity. However, in analysis of field data it has been observed that 4WD vehicles are significantly over-involved in rollover crashes.

This project conducted static rollover tests on a tilt table on a variety of 4WD wagon and utility vehicles and passenger sedans on sale in Australia. Future direction is to review the involvement in rollover crashes of equivalent categories of 4WD vehicles and passenger sedans and to compare static rollover stability to equivalent US categories.