Highway Safety Publications Catalog. Articles on Road Engineering, Road Maintenance & Management, and Injury Litigation. Information and consulting for the Automobile and Road User, as well as for law professionals in accident investigations.
TranSafety's free consumer journal for automobile and road users, three subscription journals on road maintenance, engineering, and injury litigation, and highway safety publications catalog. See our free consumer journal for automobile and road users, three subscription journals on road maintenance, engineering, and injury litigation, and a highway safety publications catalog.

The Insurance Institute for Highway Safety (IIHS) funded research conducted by the University of Maryland to find out if ignition interlock devices reduced the recidivism rate of repeat violators of drinking-and-driving laws. Ignition interlocks attach to a vehicle's ignition system and require that the driver pass a breath alcohol test before being able to start the engine. An article entitled "Ignition Interlocks Help Curb Violations Among Repeat DUI/DWI Offenders" in the May 10, 1997 Status Report described the results of that study.

Previous studies of the effect of ignition interlocks on repeat DUI/DWI offenses were inconclusive because study groups had not been randomly assigned. For the present study, Maryland researchers used a sample group of 1,380 repeat offenders of drinking-and-driving laws who had received treatment and were eligible to have their driving privileges reinstated. They randomly assigned members of the group "to either a continuing treatment program or a treatment and interlock program." Offenders participating in the interlock program received restricted licenses allowing them to drive a vehicle only if it were equipped with an ignition interlock.

Results reported a year later revealed that only 2.4 percent of those repeat offenders assigned to the interlock program had committed an alcohol-related traffic violation. The violation rate for the control group was 6.7 percent. Kenneth Beck, one of the researchers and a professor of health education at the University of Maryland, reported, "This was a statistically significant difference and indicated that being in an interlock program reduced the risk of an alcohol traffic violation within the first year by about 65 percent."

Researchers felt the ignition interlock program had fewer drawbacks that putting people in jail or impounding their vehicles. Moreover, offenders whose driving privileges are suspended or revoked often keep driving. Compared to these methods, the ignition interlock appears to be a more effective countermeasure to repeat drinking-and-driving violations--at least during the first year. Drivers involved in this study could request that interlocks be removed after a year, and most made that request. Researchers will continue to keep track of alcohol-related violations committed by the study group for another year to see if their lower repeat-offense rate continues.