Research Papers

Make them believe: Large-scale evidence from Ontario reveals how to approach the problem of drinking and driving.

Version 1
Date added June 30, 2016
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Category 2016 CARSP XXVI Halifax
Tags Research and Evaluation, Session 6A
Author/Auteur Tracey Ma
Stream/Volet Research and Evaluation

Slidedeck Presentation Only (no paper submitted)

6A - Ma


Background/Context: Both the absolute number and the per capita rate of drinking and driving (D&D) fatalities have been declining steadily in Ontario since 1990. Yet, in 2012 there were still 143 D&D deaths in the province, representing 25% of all road user fatalities that year. As such, D&D remains one of the leading causes of traffic-related injuries and fatalities. Over last 20 years, Ontario has introduced a number of D&D countermeasures. Recently, the Ministry of Transportation has completed a comprehensive impact evaluation of eight of these countermeasures.

Aims/Objectives: Ontario’s holistic approach to reduce incidents of D&D employs countermeasures that leverage different mechanisms (licence suspensions, vehicle impoundments, ignition interlocks, etc.). By examining these numerous different approaches to deterrence we hope to illuminate the most effective directions for achieving further road safety gains.

Methods/Target Group: Each of the eight countermeasures was evaluated for its ability to produce general deterrence (i.e., the effect of its existence on the behavior of all drivers) and specific deterrence (i.e., its effects on the behaviour of drivers who have been subject to it). Questions of general deterrence were typically addressed using collision outcomes, such as the number of drivers involved in D&D collisions, or the number of injuries and fatalities resulting from such collisions. Questions of specific deterrence were typically addressed with behavioural outcomes, such as repeated detection of D&D incidents. Both types of outcome measure were analyzed using controlled interrupted time series approaches wherever possible, or via matched cohort comparisons in cases where time series analysis was not feasible.

Results/Activities: All countermeasures were found to reduce D&D related outcomes under certain circumstances. New penalties that constituted an increase in severity of pre-existing sanctions, or remedial programs that are contingent upon conviction were found to reduce D&D recidivism, but produced little effect on population-level collision outcomes. In contrast, introduction of swift and certain administrative sanctions, along with public awareness and enforcement campaigns produced moderately large reductions in D&D collision related outcomes.

Discussion/Deliverables: In 2012, it was found that over 85% of alcohol-impaired drivers involved in fatal or injury collisions had no history of D&D convictions, or of administrative D&D sanctions. The largest gains in road safety can be made by focusing on countermeasures that produce general deterrence without relying on previous detection or conviction for D&D infractions. Our results suggest that creative policy directions, along with public education and enforcement campaigns aimed at increasing a potential drinking driver’s belief that he or she will be caught and sanctioned should be pursued in Ontario, with lesser focus on increasing the severity or complexity of current sanctions.

Conclusions: A drinking driver’s belief in high detection probability, and in swift and certain subsequent sanction should be fostered in jurisdictions like Ontario.

Tracey Ma