In order to eliminate potential selection bias, more RCTs need to be conducted in this area so that effectiveness, as well as efficacy, can be ascertained. The interlock programme appears to be effective while the device is installed in the vehicle of the offender. Studies need to address ways of improving recidivism rates in the long term, as the major challenges are participation rates, compliance and durability.
The Alberta Interlock Program: the evaluation of a province-wide program on DUI recidivism.
This study was designed to determine the efficacy of alcohol safety interlocks in reducing recidivism among first and second driving-under-the-influence (DUI) offenders. It also evaluates the overall effectiveness of interlock programs where typically only a small portion of DUI offenders elect to install interlocks.
                The driving records of DUI offenders participating in interlock programs for 6 months for first offenders and 2 years for second offenders were compared with similar offenders who chose not to participate.
                A province-wide program in Alberta, Canada.
                Records of 35,132 drivers convicted of DUI between 1 July 1998 and 30 September 1996 were analyzed
                Repeat DUI offenses during and after the interlock period.
                While the offenders had interlocks on their vehicles, DUI recidivism was substantially reduced. Once the interlock had been removed and the participants had been reinstated, their DUI rate was the same as other offenders indicating that the interlock reduced recidivism while in place. Because only 8.9% of eligible drivers elected to participate in the interlock program, the program did not significantly increase the overall effectiveness of the province's management of DUI offenders.
                Interlocks are associated with a major reduction in DUI recidivism while on the vehicle of the offender. However, because few offenders elect to participate, the program produces only a small (5.9%) overall reduction in the recidivism rate of all DUI offenders.