Program design for incentivizing ignition interlock installation for alcohol-impaired drivers: The Ontario approach.

•Ignition interlocks reduce drinking and driving while installed. Several issues undermine their implementation including delayed eligibility for installation, low installation once eligible, and a return to previous risk levels after de-installation.•The effectiveness of Ontario’s “Reduced Suspension with Ignition Interlock Conduct Review” Program in addressing the above issues was evaluated.•Through an incentive-based program, installation rates increased by 54% and pre-trial elapsed time decreased by 146 days. Results suggest no effect on post-interlock recidivism.•Results reveal that installation rates are responsive not only to incentivization but also to other external factors, thus presenting an opportunity for policy makers to find unique ways to influence interlock uptake, and thereby, to extend their deterrent effects to a larger subset of the population.