Ignition Interlocks – What You Need to Know: A Toolkit for Policymakers, Highway Safety Professionals, and Advocates [1st Edition]

Sprattler, Karen · 2009 · ROSA P / United States. Department of Transportation. National Highway Traffic Safety Administration

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Summary

This 2009 toolkit, authored by Karen Sprattler for the National Highway Traffic Safety Administration (NHTSA), addresses the critical issue of alcohol-impaired driving, which claimed approximately 13,000 lives in the United States in 2007. The document serves as a comprehensive resource for policymakers, highway safety professionals, and advocates, aiming to increase the adoption of breath alcohol ignition interlock devices (BAIIDs). Despite the proven efficacy of interlocks in preventing impaired driving, usage rates remain low, with only 146,000 devices in use nationally despite over 1.4 million annual DWI arrests. The toolkit synthesizes existing research, cost-benefit analyses, and programmatic considerations to guide the implementation and expansion of ignition interlock programs. The document compiles data from numerous peer-reviewed studies, meta-analyses, and state-level evaluations conducted over two decades. It reviews evidence regarding interlock effectiveness for both first-time and repeat offenders, analyzes cost structures for offenders and states, and examines compliance issues. The text draws on specific case studies from jurisdictions such as New Mexico, Maryland, Illinois, and Alberta, Canada, to illustrate recidivism rates and crash reductions. It also outlines operational challenges, including vendor management, technology selection, monitoring protocols, and strategies for addressing indigent offender funding. Key findings indicate that ignition interlocks reduce DWI recidivism by 50% to 90% while the device is installed, with an average reduction of 64%. For first-time offenders, studies show recidivism rates dropping from 7.09% to 3.51% in New Mexico and by up to 95% in Alberta. For repeat offenders, recidivism decreased by 65% in Maryland and 85% in Illinois. However, recidivism rates typically return to pre-interlock levels once the device is removed, suggesting that longer installation periods or permanent mandates may be necessary for high-risk offenders. Preliminary data from New Mexico also suggests a 32% reduction in alcohol-injury crashes correlated with increased interlock usage. Financially, interlocks are cost-effective, yielding a public benefit of $3 to $7 for every $1 spent, with daily costs to offenders comparable to the price of one or two alcoholic drinks. The significance of this toolkit lies in its practical guidance for optimizing ignition interlock programs to save lives. It highlights that while interlocks are highly effective during installation, their impact is limited by low compliance rates and short duration of use. The document recommends integrating interlocks with substance abuse treatment, enhancing monitoring of offender data to predict future risk, and addressing financial barriers through indigent funds. By providing evidence-based talking points and addressing common misconceptions, the toolkit aims to support legislative and administrative decisions that expand interlock usage, thereby reducing the substantial toll of alcohol-impaired driving fatalities and injuries.

Key finding

Alcohol ignition interlocks reduce DWI recidivism by 50 to 90 percent while installed on the vehicle, but recidivism rates return to pre-installation levels after removal.

Methodology

review

Provenance

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Topics

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• alcohol detection systems
• dui enforcement