Re-arrest rates for alcohol-impaired driving decrease by 67% after the ignition interlocks are installed compared to drivers with suspended licenses, according to research from the Community Guide branch of the Centers for Disease Control and Prevention (CDC).
Source: Effectiveness of ignition interlocks for preventing alcohol-impaired driving and alcohol-related crashes: a Community Guide Systematic Review. Elder RW; Voas R; Beirness D; Shults RA; Sleet DA; Nichols JL; Compton R. American Journal of Preventive Medicine Vol 40, No 3, 2011, pp362-376
Around 1.4 million people are arrested for driving under the influence in the United States each year and 1 million of those are convicted. Around 200,000 vehicles in the United States are fitted with interlock devices that are used to prevent drunken driving by people convicted of such offenses.
A systematic review of the literature to assess the effectiveness of ignition interlocks for reducing alcohol-impaired driving and alcohol-related crashes was conducted for the Guide to Community Preventive Services (Community Guide). The body of data included 15 scientific studies, 11 of which had been included in an earlier review in 2004.
The installation of ignition interlocks was associated consistently with large reductions in re-arrest rates for alcohol-impaired driving. Following removal of interlocks, re-arrest rates reverted to levels similar to those for comparison groups. The limited available evidence from three studies that evaluated crash rates suggests that alcohol-related crashes decrease while interlocks are installed in vehicles.
The study results indicate that interlocks, while they are in use in offenders’ vehicles, are effective in reducing re-arrest rates. However, the potential for interlock programmes to reduce alcohol-related crashes is currently limited by the small proportion of offenders who participate in the programmes and the lack of a persistent beneficial effect once the interlock is removed. Suggestions for facilitating more widespread and sustained use of ignition interlocks are provided.