Alcohol ignition interlock schemes (AISs) for drink drive offenders can be mandatory or voluntary in nature, although many include both approaches. Outcome evaluations of AISs show that they effectively reduce or eliminate drink drive offending only for as long as an interlock is installed, as once an interlock is removed risks of re-offending tend to return.
Achieving a critical mass of interlock use among drivers will increasingly develop a sense of normality about interlocks, with benefits in reducing recidivism among drink drivers as well as contributing to reduced alcohol offences and crashes among drivers generally. Increased use of interlocks can come from greater use among non-offender driver groups such as occupational drivers, inclusion of first offenders as well as repeat offenders in AISs and technological advances in interlock design relating to ease of use and tampering prevention.
Other critical operational factors relevant to AIS effectiveness include: the timing of an offender’s admission to an AIS, the degree and nature of participant monitoring while on the AIS, the type of any adjunct education, treatment or other support programs, availability of user cost subsidies, how often participants drive illegally while subject to AIS requirements, and AIS interoperability between jurisdictions.
Based on AIS evaluation findings, together with relevant theoretical and experiential perspectives, a substantial list of best practice components characteristic of effective AISs has been derived. This list can be used to gauge the potential effectiveness of and identify possible areas for improvement in existing AISs.