Study finds ignition interlock compliance-based removal laws help reduce drunk driving repeat offenses

A new research study released by the Governors Highway Safety Association (GHSA) finds that state laws dictating when ignition interlock devices (IIDs) may be removed from drunk driving offenders’ vehicles can help reduce repeat offenses. This promising finding comes halfway through what is known as the 100 deadliest days of summer, when alcohol- and drug-impaired driving rise dramatically, putting everyone on the road in danger.

Drunk driving is one of the deadliest yet most preventable behaviors that accounts for nearly one-third of the nation’s traffic crash fatalities. Alcohol-impaired driving deaths have skyrocketed by 31% in two years, rising from 10,196 in 2019 to 13,384 in 2021. IIDs, 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, such as IIDs, were installed on all vehicles, according to a 2021 Insurance Institute for Highway Safety study.

Currently, all states have some type of IID program, with 33 states and the District of Columbia having a compliance-based removal (CBR) law. Under a CBR law, drivers with an IID installed in their vehicle must have a certain number of violation-free days before the device can be removed. After surveying all states to determine which had the ability to provide reliable, accurate and complete data in a timely manner, researchers focused on two states with CBR laws (Tennessee and Washington), and two states without CBR laws (Arkansas and Iowa).

Data analyses from Jan. 1, 2016 through Dec. 31, 2019 found that the alcohol-impaired driving recidivism rates in Tennessee and Washington were 1.7% and 3.7%, respectively. Meanwhile, the recidivism rates for the two states without CBR statutes were higher, at 5.6% for Arkansas and 6% for Iowa.

“Every day, 36 people die because someone got behind the wheel after consuming alcohol. We can and must get that number to zero,” said GHSA Chief Executive Officer Jonathan Adkins. “Ignition interlocks are a powerful tool in our fight against the scourge of impaired driving. This new study suggests that enacting requirements governing the removal of IIDs can make them even more effective in preventing alcohol-impaired driving and save lives.”

The study was funded by Consumer Safety Technology, LLC (CST Holdings) and Intoxalock Ignition Interlocks. Neither were involved in the independent research, which was conducted by Tara Casanova Powell, Principal, Casanova Powell Consulting, and Dr. Ryan C. Smith under contract with GHSA.

“Ignition interlock devices help prevent impaired driving, create safer roads and save lives. Yet, there are still an astounding number of attempts to drive impaired by people who already have one installed,” said Sabra Rosener, Senior Vice President, Legislative Affairs for CST. “This new GHSA research validates that compliance-based laws are a crucial step towards effectively reducing recidivism. With stronger regulations, we can help ensure behavior change and better protect our communities. We can also empower individuals to take responsibility for their actions by giving them the tools and time necessary to make responsible choices.”

The researchers also identified challenges obtaining state impaired driving and interlock installation data, which can be housed in different repositories under the authority of separate state agencies. The report recommends that states facilitate better coordination between data managers, so they can identify and implement solutions to improve data standardization, integration and sharing.