An interlock is a device attached to a car starter that will prevent the ignition of the vehicle when a pre-set level of alcohol is detected in a breath sample. These devices have largely been used with drunk driving offenders for more than two decades to prevent them from driving while impaired. The effectiveness of these devices has been clearly demonstrated by more than two decades of research and evaluation. However, despite their proven effectiveness and the existence of enabling legislation and regulation, interlocks have been used irregularly. This situation has arisen in part because of a lack of information as well as misinformation.

To fill this gap, Alcohol Countermeasure Systems contracted the Traffic Injury Research Foundation (TIRF) to design an information package about alcohol ignition interlocks to provide judges with comprehensive, manageable and easily accessible information relating to:

• what the research concludes about interlocks;
• top reasons to use interlocks;
• how interlock devices work;
• judicial concerns about interlocks;
• state-specific information about interlock statutes and program operations;and,
• electronic, contact and research resources.