Ignition interlocks for repeat offenders

An effective measure with a real impact

This Éduc’alcool brief analysed the real impact of ignition interlock devices for repeat drunk driving offenders. The focus was on secondary actions designed for the most high-risk drivers, i.e. those whose permits have been revoked due to a drunk driving conviction.

Overall, a study of the literature indicated that, when an interlock device was installed, recidivism was 40%-95% lower than in cases where the driver’s permit was simply revoked.

The most important fact is that an interlock effectively prevents people from driving while impaired, so long as the device remains installed. Once the interlock is removed, recidivism rates are comparable to, if not higher than, those for drivers who simply had their permits revoked.

In order to obtain a residual effect, efforts must be made to change the drinking profile of the people targeted by the program during the time the interlock is installed, since drunk driving is a consequence of problem drinking.

Nonetheless, despite the absence of a residual effect, ignition interlocks are the most effective prevention tool.

Learn more about the memoire (French only)