Study: Ignition Locks Cut DUI Reoffenses, Crashes

A systematic review of 15 research studies shows that special automobile ignition locks significantly reduce the likelihood that people convicted of driving while drunk will reoffend, Reuters reported Feb. 22.

Drivers who have had an ignition interlock installed in their vehicle must blow into it to determine their blood alcohol level before they can start it. The locks are usually installed because of a court mandate after a driver has been convicted of driving under the influence.

The research review, performed by the Community Guide branch of the Centers for Disease Control and Prevention (CDC), looked at 15 studies of the ignition interlocks published through 2007. They found that on average, re-arrests for drivers with the locks installed were 67 percent lower than for drivers whose licenses were suspended, but who had no locks installed. According to the study abstract, “[f]ollowing removal of interlocks, re-arrest rates reverted to levels similar to those for comparison groups.”

Three studies that analyzed crash rates showed a drop in alcohol-related crashes for those who had the locks installed.

“The very strong indication is that ignition interlocks work extremely well with preventing people with interlocks installed from re-offending,” said Randy Elder, Ph.D., who led the study.

Although about 1 million people are arrested in the United States every year for alcohol-impaired driving, interlocks are only installed on about 200,000 vehicles. Drunk driving accounted for one-third of roadway deaths in 2009 — or almost 11,000 deaths — and cost an estimated $110 billion annually.

Currently, half the states require ignition interlocks for anyone convicted multiple times of driving while under the influence. Of those, thirteen states also require the locks for first-time offenders. The study’s authors recommended that the locks be used more widely — including for first-time offenders.

“When offenders’ licenses are suspended, they aren’t legally able to provide transportation for themselves and others who may rely on them to get to places like school and work,” Elder said. “Ignition interlocks allow offenders to keep operating their vehicles legally. At the same time, they effectively ensure that they do so more safely — not under the dangerous effects of alcohol.”

The research article, “Effectiveness of Ignition Interlocks for Preventing Alcohol-Impaired Driving and Alcohol-Related Crashes: A Community Guide Systematic Review,” appeared online in the March 2011 issue of American Journal of Preventive Medicine.

More information:
The Guide to Community Preventive Services and Recommendations for Reducing Alcohol-Impaired Driving