Research Papers

An Evaluation of Nova Scotia’s Alcohol Ignition Interlock Program

Version 1
Date added June 30, 2016
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Category 2016 CARSP XXVI Halifax
Tags Research and Evaluation, Session 6A
Author/Auteur Ward G.M. Vanlaar, Marisela Mainegra Hing, Robyn D. Robertson
Stream/Volet Research and Evaluation

Slidedeck Presentation (final paper delayed)

6A - Hing

Abstract

Background/Context: Alcohol ignition interlock programs for offenders aim to reduce recidivism among convicted drunk drivers. Despite the existence of alcohol ignition interlock programs for more than three decades, jurisdictions continue to be challenged with the implementation of these programs. In 2008 Nova Scotia implemented an Alcohol Ignition Interlock Program (AIIP). The Traffic Injury Research Foundation (TIRF) was hired by the Province of Nova Scotia to evaluate their AIIP.

Aims/Objectives: To evaluate Nova Scotia's AIIP and to help identify areas for improvement.

Methods/Target Group: Different types of data were used including conviction and crash records of individual participants; self-administered questionnaires to measure specific attitudes and behaviour; provincial monthly counts of charges, convictions and crashes from 1998 to 2013; and interlock logged events. For each type of experimental data (alcohol-related convictions and crashes of interlock participants), control data (non-alcohol-related charges, convictions and crashes of non-interlock participants) were also used. The data were analyzed using several methods including descriptive statistics, survival analysis, time series analysis and logistic regression analysis.

Results/Activities: With respect to specific deterrence (i.e., preventing recidivism) there was strong evidence to suggest that participation in the interlock program reduced the risk of alcohol-related charges for the participants during and after the program. To illustrate, there was a 90% reduction in recidivism among a study group since participation in the program and a 79% reduction after participants in this group exited from the program. With respect to general deterrence (i.e., referring to a preventative effect on the entire population of drivers in Nova Scotia) there was a temporary decrease in the number of alcohol-related charges (13.32%) and convictions (9.93%) in the first and seventh month respectively following the implementation of the program. There was also some weaker evidence that there was a permanent decrease in the number of alcohol-related crashes with fatal and serious injuries every month since the tenth month after the beginning of the program.

Discussion/Deliverables: The AIIP had a positive impact on road safety in Nova Scotia and it was associated with reduced levels of drink driving recidivism. The evidence suggests the interlock program was better at preventing harm due to alcohol-impaired driving than the alternative of not using the interlock program.

Conclusions: Recommendations based on the evidence from this study were formulated supporting the continuation of the AIIP in Nova Scotia and to consider some areas for improvement such as performance-based exit, monitoring and levels of risk in relation to non-compliance.

Ward G.M. Vanlaar, Marisela Mainegra Hing, Robyn D. Robertson