Citation

Keall MD, Newstead SV. Monash University, 978-1-925413-27-4. Clayton, VIC, Australia: Monash University Accident Research Centre, 2021.

Copyright

(Copyright 2021, Monash University)

The full document is available online.

Abstract

factured from 2008 to 2017 in five Australian States and New Zealand, around 23% of drivers involved in such crashes resulted in a fatal or serious injury to the driver. In all crash types, the corresponding proportion was just less than 5%. These types of crashes are therefore particularly important to prevent. This study sought to estimate crash rates associated with the effectiveness of two vehicle technologies useful for preventing rollovers, ESC and RSC.


Two analyses were conducted on Australasian crash data and licensing data for vehicles manufactured from 2008 onwards. The first analysis looked at vehicle rates of rollover per year licensed in relation to ESC fitment. A comparison was made between rollover rates for high riding vehicles (light commercial vehicles – vans and utes, and SUVs) compared to cars. A much lower rate of rollover was associated with ESC fitment relative to non-fitment for high riding vehicles (0.30) than for cars (0.53), consistent with ESC being more effective at preventing rollovers for the high-riding vehicles. For vehicles not fitted with ESC, the rollover rate associated with high riding vehicles was almost twice that of cars (1.9 times, 95% CI 1.71- 2.11) but for vehicles fitted with ESC, there was no significant difference between the rollover rates estimated for high riding vehicles and cars (1.06 times, 95% CI 0.93-1.20). When the analysis focused on individual market groups, there was a much lower rate of rollover associated with ESC fitment relative to non-fitment for small and large SUVs in particular. Although not as pronounced, there were also low relative rates for small and light cars, and for commercial utes.


The second analysis examined the association between RSC fitment and rollovers for high riding vehicles by analysing crashes for the years 2008-2017 from Victoria, Queensland, South Australia, New South Wales, Western Australia and New Zealand. The analysis was restricted to vehicles already equipped with ESC as vehicles fitted with RSC always have ESC fitted. There was a statistically significant odds ratio of 0.76 (95% CI 0.62-0.93) associated with RSC fitment for these vehicles, controlling for driver age, sex, jurisdiction and speed limit of the crash. Analysis by particular market groups found significant odds ratio reductions for commercial utes and large SUVs, but not for the other high riding market groups individually.


This analysis of crash rates is consistent with greater effectiveness of ESC in preventing rollovers for high riding vehicles, to the extent that there was no difference between the rates of rollover for ESC-equipped high riding vehicles compared to ESC-equipped cars, despite much higher rates for those not equipped. The analysis was also consistent with the additional fitment RSC being effective in preventing almost an additional quarter of all rollover crashes for high riding vehicles equipped with ESC. This suggests that these technologies are highly desirable, and more desirable for higher riding vehicles.