Ignition Interlocks

Ignition interlocks are an increasingly widespread penalty handed out by states for DUI convictions. Below, you can find resources regarding the effectiveness of ignition interlocks at curtailing risky driving behavior, how to implement a state interlock program, and suggestions for future interlock policy permutations.

Ignition Interlock Report, NCSC, 2018.  This report reviews the latest research on ignition interlock programs and how they are used from a national perspective (2013-2017). The appendix contains a detailed chart of each state’s ignition interlock program and a comprehensive resource list. 

2016 Annual Ignition Interlock Survey: United States, Traffic Injury Research Foundation USA, Inc. (May 2017). This is TIRF’s annual update on the state of ignition interlock laws and enforcement in the United States. The report analyzes traffic crash and the changes in that data from year-to-year, and it provides information about new legislation and policies implemented from state to state.

Interlock Data Utilization, NHTSA (August 2017). This report summarizes findings on ignition interlock data that is used for DWI offender monitoring and offender-related programs such as screening, assessments, and treatment for alcohol abuse problems. It describes the uses of interlock data, procedures for using interlock data, and challenges and issues related to using interlock data.

The Feasibility of Voluntary Ignition Interlocks as a Prevention Strategy for Young DriversNHTSA (June 2017). This study examined the feasibility of implementing a voluntary alcohol ignition interlock program as a preventative approach through discussions conducted in 2010 with ignition interlock manufacturers and service providers, insurance companies, community groups, parents, teens and young adults. Additionally, ignition interlock recorder data on users 16 to 26 years old were examined, and a web survey with parents of voluntary users and voluntary users themselves was analyzed.

An Examination of the Feasibility of Alcohol Interlocks for Motorcycles, NHTSA (June 2017). This report reviews information on alcohol ignition interlocks to help determine whether they can be an appropriate DUI countermeasure when installed on motorcycles operated by convicted DUI offenders. The report summarizes issues of perceived liability, technical barriers, statutory or legislative barriers, and other factors related to this issue.

Maryland's Ignition Interlock Program: Status Report, Maryland Department of Transportation (February 2017). This report details the state of Maryland’s ignition interlock program as of early 2017. The state implemented a mandatory interlock program for all offenders in 2016. The report details some of the circumstances surrounding that implementation, and it summarizes data from the program up to the time of the report, though most of the data in this report focused on characteristics, demographics, and outcomes before the end of completion of the interlock program.

Minnesota Ignition Interlock Program Evaluation, Greenway Transportation Planning/Minnesota Department of Public Safety (2016). This report tracked the success of Minnesota’s ignition interlock program and compared it against other programs across the country. The program found that program participants were less than half as likely to reoffend as non-participants after the program had ended. The report made several recommendations, including making the program mandatory for all DWI offenders and increasing the role of treatment.

Michigan DWI/Sobriety Court Ignition Interlock Evaluation, Christopher A. Kierkus, PhD, and Brian R. Johnson, PhD (2016). This report was designed to provide the Michigan state government with analysis and documentation regarding to the implementation of its ignition interlock program. The report showed that approximately 97% of driver ordered to install interlocks on their vehicles have complied with those orders. The report showed that interlock installation was positively correlated with levels of education and employment status. The study found that approximately three times more clients of DWI court without an interlock failed their programs than clients who had an interlock installed. The study also found that interlock program participants had the lowest rate of recidivism after one, two, three, and four years of follow up.

Alcohol Interlocks and Drink Driving Rehabilitation in the European Union: Best practice and guidelines for Member States, European Transport Safety Council (December 2016). This report discusses drunk driving and gives an overview to its background in Europe, while also discussing some historical methods of preventing drunk driving. The report then goes on to look at interlock programs from five European countries. Finally, the report provides a framework for a successful interlock program to countries that are considering implementing such a program.

Mandating Treatment Based on Interlock Performance: Evidence for EffectivenessAlcoholism: Clinical and Experimental Research (September 2016). This study used Florida interlock data to analyze the success of combining alcohol use disorder treatment with interlock data. The study found that individuals who received AUD treatment after a certain number of interlock violations were statistically less likely to reoffend following the removal of the ignition interlock. The study estimated that the decline in recidivism prevented a measurable number of rearrests, crashes, and traffic injuries.

Impact of State Ignition Interlock Laws on Alcohol-Involved Crash Deaths in the United States, American Journal of Public Health (May 2016). This study analyzed NHTSA crash data from 1999 to 2013 and compared alcohol-involved crash deaths between states with and without interlock requirements. The study found that requiring ignition interlocks for all impaired driving convictions led to 15% fewer alcohol-involved crash deaths. The study recommended wider use for interlocks.

Evaluation of State Ignition Interlock Programs: Interlock Use Analyses From 28 States, 2006–2011, NHTSA (2015). This NHTSA study evaluated ignition interlock data from just over half of the states in the United States. The study concluded that requirements and incentives had the strongest positive relationship to higher interlock use rates, while monitoring, coordination, uniformity, and education were moderately to strongly related to higher interlock use rates.

Countermeasures That Work: A Highway Safety Countermeasure Guide For State Highway Safety Offices, NHTSA (November 2015). This NHTSA resource on a wide variety of traffic safety countermeasures includes a small section on ignition interlocks.

Modeling the Injury Prevention Impact of Mandatory Alcohol Ignition Interlock Installation in All New US Vehicles, American Journal of Public Health (May 2015). This study analyzed the cost effect of installing ignition interlocks in every new vehicle sold in the United States. The study concluded that 85% of crash fatalities and 84 to 88% of nonfatal injuries attributed to impaired drivers would be prevented. The study estimated that savings would overtake costs after approximately three years of such a program.

Nova Scotia Alcohol Ignition Interlock Program: Outcome Evaluation, TIRF (April 2015). This report evaluated the success of Nova Scotia’s ignition interlock program. The study found strong evidence that interlocks reduced alcohol-related charges for participants while they were installed. There was weaker evidence to suggest a broader decrease in the number of alcohol-related charges was the result of the program or that the program permanently decreased alcohol-related crashes and fatalities. The report concluded that interlocks were a net positive for road safety, though.

DWI Recidivism in the United States: An Examination of State-Level Driver Data and the Effect of Look-Back Periods on Recidivism Prevalence, NHTSA (2014). This NHTSA Traffic Safety Facts Research Note compared data on DWI recidivism with previous NHTSA data and extrapolated reasons as to why that may have been the case. It also offered some suggestions to take into account when looking at interlock policy.

Ignition Interlocks – What You Need To Know: A toolkit for program administrators, policymakers, and stakeholders, 2nd Edition, NHTSA (February 2014). This background resource on ignition interlocks includes a description of an interlock device and how it works, a discussion of interlock technology, research about interlocks, and guidelines on program implementation, vendor selection, and program costs. The guide also discusses the status of each state’s ignition interlock program, and it includes forms and checklists to assist with implementing such programs.

Technical Development and Deployment of Alcohol Interlocks in Road Safety Policy: Study, European Parliament (2014). This is a study on the use, effectiveness, and contribution to road safety of ignition interlocks in the European Union. The report discusses the cost-benefit analysis from installing interlocks and the potential to reduce road fatalities by installing interlocks on certain specified classes of vehicles. The authors recommended a series of policy goals and implementation measures to be taken across the EU.

Evaluation of the Washington State Ignition Interlock Pilot Program 2009: 2012 Recidivism Report, Washington Traffic Safety Commission (April 2014). This report tracked compliance with the Washington State ignition interlock program. The report found increased level of installation compliance, but also found a high rate of drivers acting (or at least seeming to act) in noncompliance after installation of the interlock. The report found that interlocks decreased the rate of recidivism in second- and subsequent-drive offenders, but not first-time offenders.

Model Guideline for State Ignition Interlock Programs, NHTSA (November 2013). This is a series of directions and suggestions from NHTSA on how to create an effective ignition interlock program.

Administrative Reinstatement Interlock Programs: Florida, A 10-Year Study, Alcoholism: Clinical and Experimental Research (July 2013). This study of Florida’s ignition interlock data found that almost all drivers who qualified for license reinstatement participated in Florida’s interlock program, but fewer than half of the DUI offenders who had completed the period of mandatory revocation actually qualified for reinstatement.

Ignition interlock institutes: Promoting the use of interlocks and improvements to interlock programs, Mothers Against Drunk Driving (July 2013). This is a report by Mothers Against Drunk driving done for NHTSA. The report details a program of education and advocacy for the increased of ignition interlocks. The report discusses barriers to implementing interlock programs and potential solutions to those problems.

Effectiveness and impact of alcohol interlock-controlled driving rights, Finnish Transport Safety Agency (June 2013). This study analyzed the effects of Finland’s alcohol ignition interlock program. It found that the recidivism rate in the group analyzed was significantly smaller, both during and after installation, than the broader group of people convicted of driving while intoxicated. The study made a broad variety of recommendations based off of the data collected and the experiences of people in the program.

Case Studies of Ignition Interlock ProgramsNHTSA (April 2012). This is a compilation of six case studies on the use of ignition interlocks. The states profiled include Colorado, Florida, Illinois, New Mexico, New York, and Oklahoma. Rather than evaluating the impact of ignition interlocks, the study is a lengthy look into the unique ways each states implemented ignition interlock programs, looking specifically at legislation, funding, program administration, potential issues, and evaluation of the programs.

Ignition Interlock Program FAQ, Vermont Department of Motor Vehicles (2017). This document is an extensive FAQ for ignition interlock users, covering most facets of Vermont's program.

VASAP Ignition Interlock Agreement, Virginia Alcohol Safety Action Program (2015). This document is the agreement that DUI offenders in Virginia who install an ignition interlock in their vehicles must sign.