Follow-up of subsequent crash and offence records of offending drivers who either did or did not attend a driver intervention program

Abstract

The Driver Intervention Program (DIP) is a 90-minute interactive, small-group workshop for disqualified L- or P-plate drivers, aged 25 and under, living in Adelaide and in some rural centres close to Adelaide. The present paper compares the subsequent crash and driving offence experience of two groups of offending drivers: those attending DIP, and those who should have attended DIP but chose not to and pay an expiation fee instead. No experiment was performed: the drivers themselves chose whether or not to attend the DIP, and any difference between DIP and Expiation groups in subsequent crashes and offences could be due not to attendance at DIP but instead to pre-existing differences between the groups (in geographical, social, psychological, and other factors). Licence numbers of drivers eligible for DIP (i.e., who had committed an offence) were matched against the database of crashes and against the database of driving offences. The sample consisted of those sent their first Notice to Attend in 2001 or 2002. The following results refer to the 18 months following the issuing of a Notice to Attend DIP. There was no evidence that the DIP group had a lower rate of crashes than the Expiation group, but it did have an appreciably lower rate of moving offences and a much lower rate of administrative offences than the Expiation group. Our interpretation is that the DIP is having no substantial effect, and that the differences between groups in respect of driving offences are due to the factors that influence the decision whether to attend DIP or not. Note, however, that the DIP is a very cheap countermeasure, and thus we cannot say that the DIP is not cost-effective. There is literature on effects of various interventions on offences differing from their effects on crashes. A likely explanation is that linkage of behaviour to crashes is looser than linkage of behaviour to being caught offending.