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Increasing Alcohol Ignition Interlock Use: Successful Practices for States

	ignition interlock

What is an alcohol ignition interlock?

An alcohol ignition interlock is a breath-test device connected to a vehicle’s ignition. The vehicle will not start unless the driver blows into the interlock and has a blood alcohol concentration (BAC) below a pre-set low limit, usually .02 BAC.

Keep your state safe—increase alcohol ignition interlock use

Ignition interlocks reduce repeat offenses for driving while intoxicated (DWI) by about 70% while they are installed. All states have implemented ignition interlock programs to manage interlock issues and monitor offenders who are required or eligible to install them. Despite these laws and programs, only about one-fifth of those arrested for DWI have interlocks installed.

How can states increase alcohol ignition interlock use?

To achieve and sustain high ignition interlock use, states may consider the following eight program keys that can be used to strengthen state Alcohol Ignition Interlock Programs. These program keys were identified through a collaborative evaluation* that looked at characteristics of existing state interlock programs associated with increases in interlock use. Implementing just one of these program keys is likely to increase interlock use. Implementing multiple program keys is associated with even higher increases in interlock use.

Eight program keys for strong state alcohol ignition interlock programs

Program KeyCharacteristics of a Strong Program KeyExample
Require or incentivize useRequirement or strong incentive to install interlocksA law covering all offenders with significant reduction of hard license suspension period if interlock is installed
Levy strong penaltiesStrong, swift, and appropriate penaltiesExtension of interlock time, home monitoring, jail time if refuse to install, fail breath test, or tamper or otherwise circumvent interlock
Monitor interlocks to ensure proper useCareful monitoring to assure interlocks are installed and used as intendedRandom checks by DMV, probation, or treatment centers to ensure offender has installed and is using an interlock
Implement uniformly across stateUniform and consistent implementation, statewideAll agencies report data regularly in compatible format, using uniform definitions of violations in same time frame
Coordinate across agenciesClose coordination and communication across all agenciesRegular communication with representatives from all interlock program involved agencies
Educate stakeholders about the programRegular training or education for all interlock agency staff and managementRegular trainings between interlock program managers, law enforcement, vendors, DMV, and court staff
Provide adequate resourcesAdequate staff and funding resourcesDesignated interlock program manager and staff, financial assistance for offenders
Use data for actionExcellent data records (including level of offense, BAC level at time of arrest, number of prior arrests, installation/ removal dates, violations)Combined annual data on offenders available from all agencies to monitor offenders, report violators and evaluate program effectiveness
*Program keys were derived from an evaluation conducted in 2014 by the Centers for Disease Control and Prevention (CDC), the National Highway Traffic Safety Administration (NHTSA), and the Governors Highway Safety Association (GHSA) and produced by the Preusser Research Group. The evaluation looked at key features of interlock programs and use of interlocks in 28 states from 2006–2011. Each state’s program keys were rated and correlation analysis was used to determine which were related to higher interlock use. The full report, Evaluation of State Ignition Interlock Programs: Interlock Use Analysis from 28 States, contains additional data, analyses, discussion, and examples of strong program keys from various states. Download the report: Evaluation of State Ignition Interlock Programs:Interlock Use Analyses From 28 States, 2006–2011.

Read the reports

	ignition interlock

Increasing Ignition Interlock Use: Successful Practices for States (full document) [PDF - 4 MB]

This publication is based on an evaluation conducted in collaboration with the Centers for Disease Control and Prevention (CDC), National Highway Traffic Safety Administration (NHTSA), and Governors Highway Safety Association (GHSA). The evaluation looked at key features of interlock programs and use of interlocks in 28 states from 2006–2011. Each state’s key features (Program Keys) were rated and correlation analysis was used to determine which keys were related to higher interlock use.

	Cover of Evaluation of State Ignition Interlock Programs:Interlock Use Analyses From 28 States, 2006–2011
Evaluation of State Ignition Interlock Programs:Interlock Use Analyses From 28 States, 2006–2011

In 2010, the Centers for Disease Control and Prevention (CDC) and NHTSA began collaborating on a project to evaluate ignition interlock programs in selected States. The purpose of the evaluation was to provide information and best practices to States for ignition interlock programs. The project was managed by the Governor’s Highway Safety Association and conducted by the Preusser Research Group.

This report provides the results from the first part of the project that had the following objectives: determine how States can increase interlock use among DWI offenders who are required or eligible to install one; determine which changes in ignition interlock programs led to increases in ignition interlock use; identify the key features of ignition interlock programs; determine which key program features were related to higher ignition interlock use rates.

 

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