States with Ignition Interlock Laws Have Fewer Repeat Drunk Driving Offenders: Report

Only two-thirds of states have laws requiring ignition interlock devices, which are proven to reduce drunk driving and improve the safety of U.S. roadways.

States that enact laws dictating when drivers can remove ignition interlock devices, which are used to test blood alcohol levels before operating a motor vehicle, may substantially reduce the number of drunk driving related auto accident deaths,  according to new data from state highway officials.

The Governors Highway Safety Association (GHSA) released a new report late last month, indicating that states with compliance-based removal laws for ignition interlock devices have nearly 4% fewer drunk driving arrests involving repeat offenders. Researchers say the findings suggest drunk driving offenses could decrease nationally overall if more states had stricter device removal laws.

Drunk driving is one of the deadliest, yet most preventable behaviors, accounting for nearly one-third of the nation’s traffic crash fatalities. Alcohol-impaired driving deaths have skyrocketed 31% in just two years, rising from 10,196 in 2019 to 13,384 in 2021. Studies show one third of those alcohol related deaths involve repeat drunk driving offenders.

Safety experts say ignition interlock devices (ILDs), which prevent a vehicle’s engine from starting if alcohol is detected on the driver’s breath, are a proven and effective tool for significantly reducing drunk driving. Nearly 12,000 roadway deaths could be prevented each year if alcohol detection systems like IIDs were installed on all vehicles, according to a 2021 study.

While recent surveys show ILD devices and similar vehicle technology to prevent impaired driving have broad public support, only 33 states and the District of Columbia currently have compliance-based removal laws. Those laws state that drivers with ILDs installed in their vehicles must maintain a set number of violation-free days before the devices can be removed.

States with Stricter Ignition Interlock Device Rules Have Fewer Repeat Drunk Drivers

For this latest study, GHSA researchers collected data on alcohol impaired repeat driving offenses between January 1, 2016, and December 31, 2019 for four states: Tennessee, Washington, Arkansas, and Iowa. Tennessee and Washington currently have compliance based ILD removal laws, while Arkansas and Iowa do not.

The IIHS researchers determined that the more stringent, compliance based removal laws in the two states contributed to significantly lower repeat drunk driving offenses, compared to the two states without such laws. After comparing the data, researchers found that Tennessee and Washington repeat drunk driving rates were 1.7% and 3.7%, respectively. By comparison, The repeat drunk driving rates in Arkansas and Iowa were 5.6% and 6%.

Researchers identified compliance based removal laws as an effective tool to reduce potentially deadly repeat drunk driving offenses, and urged states without such laws to consider adopting them.

“While there are several factors that can affect drunk driving recidivism, the data indicates that CBR requirements can be a promising tool to address these high-risk drivers and that states without these laws should consider implementing them,” the researchers concluded.