Industry Research

NCSL 2023 Legisbrief Highlights Effective State Legislation


This National Conference of State Legislatures new publication details five specific ways states can strengthen ignition interlock laws.

MADD State Law Overview 2022 All States

238 Legislative recommendations by Mothers Against Drunk Driving to improve lifesaving ignition interlock laws.

Ignition Interlock 2021 MADD Report

MADD research shows ignition interlocks are effective in changing behavior and are a valuable tool for saving lives and preventing injuries on our nation’s roads.

State alcohol ignition interlock laws and fatal crashes | October 2021

Research by IIHS proves laws mandating alcohol ignition interlocks, especially those covering all offenders, are an effective impaired-driving countermeasure that reduces the number of impaired drivers in fatal crashes.

State Alcohol Ignition Interlock Laws and Fatal Crashes | Insurance Institute for Highway Safety | March 2018

The IIHS research reported that in states with all-offender IID laws, 16% fewer drivers with a .08 or greater BAC were involved in fatal alcohol-involved crashes.

Effects of Washington State’s Alcohol Ignition Interlock Laws on DUI Recidivism: An Update | Insurance Institute for Highway Safety | March 2018

IIHS first studied the effects of IID laws on drunk driving recidivism in 2013 and this 2018 report provides an update on the research. The study concludes that over the five-year period as the laws were improved, the number of ignition interlocks installed on driver’s vehicles increased, decreasing drunk driving recidivism of first-time offenders.

2.3 Million Attempts to Drive Drunk Stopped By Ignition Interlocks | Mothers Against Drunk Driving | February 2018

Research by MADD shows that ignition interlock devices have stopped 2.3 million attempts by offenders to drive drunk with a BAC of .08 or greater in the United States through 2017.

Ignition Interlock Laws: Effects on Fatal Motor Vehicle Crashes, 1982-2013 | Emma E. McGinty, American Journal of Preventative Medicine | January 2017

This study looks at how ignition interlock laws can reduce fatal crashes and concludes that having mandatory interlock laws for all offenders would significantly benefit public health. The research concluded that all-offender laws for first-time offenders with a BAC of greater than .08 were associated with a seven percent decrease in fatal drunk driving crashes, and laws for first-time offenders with a BAC of greater than .15 were associated with an eight percent decrease in fatal drunk driving crashes. Furthermore, McGinty finds laws requiring interlocks for segments of high-risk drunk driving offenders may reduce alcohol-involved traffic fatalities after 2 years of implementation.

Study of Four County Ignition Interlock Pilot Program | California DMV | June 2016

The study conducted by the California Department of Motor Vehicles in four counties (Alameda, Los Angeles, Sacramento, and Tulare) found that ignition interlock devices are 74% more effective in reducing drunk driving recidivism than license suspension for first time offenders.

Impact of State Ignition Interlock Laws on Alcohol-Involved Crash Deaths in the United States | EJ Kaufman, University of Pennsylvania | March 2016

This study correlates the number of fatalities from drunk driving and the use of ignition interlocks. The study found that DUI deaths decreased by 15% in states that have all-offender interlock laws.

Michigan DUI/Sobriety Court Ignition Interlock Evaluation | The Michigan Association of Treatment Court Professionals | 2016

Key findings in the Michigan study found that people who were ordered to be on an interlock device had less recidivism over the course of a four-year period than offenders who were not on an interlock or were on standard probation.

Locked and Not Loaded: First time Offenders and State Ignition Interlock Programs | Darin F. Ullman, International Review of Law and Economics 45 | 2016

Ullman’s research looks at vehicular fatality data across the United States and examines the effectiveness of mandatory interlock laws in reducing alcohol-related fatalities. He concludes mandatory all-offender laws can reduce alcohol-related traffic fatalities by nine percent and suggests his research provides evidence to policy makers as to why all offenders should participate in interlock programs.

Safety Report Reaching Zero: Actions to Eliminate Alcohol-Impaired Driving | National Transportation Safety Board | 2013

While the NTSB makes the point that license suspension or license revocation laws are effective in reducing alcohol-impaired motor vehicle crashes, the agency says that these laws can be strengthened by requiring first-time offenders to install ignition interlock devices as a condition of license reinstatement.

Highway Special Investigation Report Wrong-Way Driving | National Transportation Safety Board | 2012

The NTSB found that over the last two decades, ignition interlock devices were effective in reducing drunk driving recidivism. One study that assigned offenders randomly found that when assigned to an interlock or other control program, that there was a 36 percent reduction in recidivism after the interlock was removed.