The potential effectiveness of young driver high-performance vehicle restrictions as used in Australia

Young drivers persistently have higher crash rates despite various countermeasures targeted at their risk factors and exposures. A potentially high risk situation for novice drivers may feasibly include the driving of high performance vehicles, which are subject to restrictions for probationary and restricted drivers in four Australian States. High performance vehicles are capable of high levels of acceleration and speed, which may encourage unsafe driving behaviours, particularly when driven by novice drivers, who may lack appropriate judgement and experience. This research sought to identify potential safety benefits of restrictions on certain vehicles for novice drivers using crash data from Australia and New Zealand, and vehicle licensing data from New Zealand. Data on crashed vehicles and their drivers were analysed to estimate the prevalence of the high performance vehicles in the fleets considered, particularly when driven by young people. By matching New Zealand licensing data with crash data, it was possible to estimate the risk of these high performance vehicles relative to other vehicles in the fleet. For owners aged under 25, a statistically significant 69% elevated injury crash involvement risk ratio was estimated for the high performance vehicles subject to restrictions in Australia in comparison with their risk with other vehicles controlling for other relevant factors (with 95% CI 30-123%, using owners aged 40-59 as a comparison group). Injuries in the vehicles of young owners of high performance vehicles were estimated to increase compared to their rate in other vehicles by 101% (with 95% confidence interval 69-171%, using owners aged 40-59 as a comparison group). Despite the higher relative risk for the high performance vehicles, they were relatively rare in the fleets studied, and the potential reduction in young driver injury rates from banning these vehicles was estimated to range from 0.4% in New Zealand to 2.5% in the Australian States of Queensland and Victoria. In addition, the potential reductions estimated here also depend on unrealistic assumptions of 100% compliance with regulation and the adoption of less risky driving behaviour in response to lower performance vehicles. Although these vehicles have a statistically significantly higher crash and injury risk than other vehicles when owned by young people, there are considerable costs of implementation and ongoing enforcement in imposing vehicle restrictions for young drivers that may not outweigh these potential safety benefits.