TIRF USA, in partnership with Greenway and Vanasse Hangen Brustlin, Inc. conducted a comprehensive evaluation of the ignition interlock program in Colorado. Driving under the influence of alcohol is a persistent traffic safety problem in Colorado, and elsewhere. Colorado has implemented several evidence-based best practices aimed at addressing this problem, including an Ignition Interlock Device (IID) Program. Interlock programs have been proven to reduce alcohol-impaired driving. More recently, studies have shown that interlocks can also reduce alcohol-related crashes and fatalities.

The purpose of the project was to evaluate the impact of the interlock program on alcohol-impaired driving with a goal of reducing impaired driving recidivism rates in the state. The period between Jun. 1, 2010 and Dec. 31, 2013 provided a baseline for comparison purposes. Several agencies provided data to support this evaluation. A comprehensive review of Colorado’s interlock program, education and treatment programs, and probation services was conducted to determine the current impact and efficacy of these programs, individually and combined, in their goal to reduce impaired driving recidivism rates.

Findings from the evaluation of Colorado’s interlock program demonstrated the IID program is effective. The combined use of education, treatment, and probation services in their IID program plays a significant role in reducing recidivism rates. In fact, results showed the chances of recidivism were reduced by half using this approach. While the results of this study demonstrated the Colorado interlock program was successful in reaching its objectives, the findings also suggested potential improvements to strengthen the delivery of the interlock program.