Association between supervisory driver offences and novice driver crashes post-licensure

This research explore associations between driving offences of learner supervisory drivers and subsequent crashes as novice independent drivers in a prospective cohort of 20,822 drivers aged 17-24 in New South Wales, Australia, on their first independent driver licence. Information on demographics, primary supervisory drivers, and various risk factors was collected via an online questionnaire and subsequently linked to police-reported crashes two years later. Poisson regression determined that the unadjusted relative risk of crash was 1.35 (CI 1.14-1.60) for novices whose supervisors had offences, with this association remaining when adjusting for supervisor age, gender and relationship to the novice (RR=1.37, CI 1.16-1.63), but not when additionally controlling for novice driver demographics and characteristics (RR=1.50, CI 0.83-2.70). These findings suggest newly-licensed drivers previously supervised by drivers with recent traffic offences have a one-third higher risk of crashing. This risk is independent of the supervisor demographics, but mitigated by the young drivers' personal characteristics. Careful consideration should be given to policy developments regarding supervised driving requirements that rely heavily on parents to adopt this role.