The effects of Ontario's administrative driver's licence suspension law on total driver fatalities: A multiple time series analysis

Aims: On 29 November 1996, Ontario introduced an Administrative Driver's Licence Suspension (ADLS) law, which required that anyone charged with driving with a Blood Alcohol Concentration (BAC) over the legal limit of 80 mg% or failing to provide a breath sample would have their licence suspended for a period of 90 days at the time the charge was laid. This study evaluates the effects of Ontario's ADLS law on total driver fatalities over a 25-month period after the law was introduced, and compares Ontario's experience with that of two comparison provinces (Manitoba and New Brunswick) that did not introduce ADLS at that time. Methods: Interrupted time series analysis with ARIMA modeling was applied to the monthly number of drivers killed in Ontario and the control provinces for the period 1 January 1988 to 31 December 1998. Findings: A significant intervention effect was found in Ontario, with ADLS being associated with an estimated reduction of 14.5% in the numbers of fatally injured drivers. No corresponding effect was observed in the control provinces. Conclusions: These data provide evidence that the law produced a general deterrent effect resulting in a reduction in total driver fatalities.