Traffic Injury Research Foundation, USA Inc.

The knowledge source for safe driving



Minnesota Ignition Interlock Evaluation

The Traffic Injury Research Foundation USA (TIRF USA) and VHB, Inc. were contracted by Greenway Transportation Planning to participate in an evaluation of the Minnesota ignition interlock program. The goal of this project was to examine the effectiveness of the Minnesota ignition interlock program and to provide a comprehensive report to the project sponsor – the Minnesota Department of Public Safety, Office of Traffic Safety. The evaluation examined program participation and outcomes compared to eligible drivers who did not have an interlock installed.

The study was guided by key research questions examining several specific components of the program. The evaluation focused on the performance of the participants during and after completion of the interlock program. The target population included all drivers with DWI convictions since the start of the two-county pilot program in July 1, 2007. Data included basic demographic information, vehicle ownership, driving convictions and related interlock-program events, and participant survey data. The evaluation provided knowledge on participation rates as well as participant characteristics and DWI incidents. Performance indicators included program completion rate, recidivism (during and after completion) and device failed attempts, among others.

The evaluation revealed the Minnesota interlock program improved public safety by reducing recidivism among those who had driven while intoxicated. Program participants experienced fewer arrests for DWI and moving violations while in the program compared to the comparison group. Program participants were less than half as likely to commit a new DWI offense compared to a matched group of non-participants. The evaluation also showed participation in the Minnesota program reduced the long-term risk of recidivism by 39% overall. Of those for whom this was a first DWI violation, there was a further 12% reduction in risk of recidivating. The findings from this study are consistent with other national interlock evaluations that considered recidivism. Recommendations to further improve the program are also included in the report. (see link below)

Project Status: Published

Project Sponsor(s)


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Traffic Injury Research Foundation USA, Inc.
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