Program effects were tested through a series of logit regressions, and program and comparison group drunk-driving survival rates were also compared. Ignition interlock prevents operation of a vehicle when an individual is drunk, but still allows driving when the operator is sober. The vehicle will not start in any situation in which an individual has imbibed too much. The sample in this study consisted of 994 offenders aged 20 and older. A total of 168 ignition interlock program cases and 826 impaired drivers in the comparison group were used in the study. Findings show that participation in an ignition interlock program reduced the likelihood of recidivism for impaired driving, high-risk driving, and injury collisions. When compared to a group that received only license suspensions, ignition interlock program participants were twice as likely to avoid repeat drunk driving. Ignition interlock cases were 4.4 times less likely to record a new serious driving violation and 3.9 times less likely to be involved in an injury collision. These results were more supportive of ignition interlock than evaluations conducted in Ohio and California and more consistently positive than outcomes observed in Oregon. A potentially confounding factor, program operation, offers a plausible explanation for the Alberta ignition interlock program's greater success. 2 tables, 2 figures, 2 notes, and 35 references