Since 1995, DUI offenders assigned to the interlock have been under study to assess the impact of a four-part program of supportive guidance in Alberta, Canada. The program combines motivational interviewing with education, planning and referrals. The purpose of the program is to attempt to slow the expected rate of increase in DUI re-offences once the interlock is removed. Success is measured by lower repeat DUI after the interlock is removed. There are two primary data sources to document an impact of supplemental services: the interlock's internal event recorder and the driving record. Over 2300 interlock offenders taking a median of more than 2000 breath tests, were studied during the full period the interlock was installed. The proportion of warn (i.e., BAC .02-.039% = 20-39 mg/dl) and fail (i.e., BAC 3.04% = 34O mg/dl) violations declined by over 50% during the course of the installed period. Those drivers in the intervention site were regularly interviewed about their drink-driving choices and encouraged to do more planning to separate drinking and driving. Findings show that those in the city where the intervention was offered were less likely to have fail-level BACs when attempting to start their cars. Other predictors of more failed BAC tests (as a proportion of all tests taken to start the car) include more reported drinking at baseline, being mandated to the interlock as a condition of license reinstatement, being unmarried, and having more prior offences. The failed interlock BAC tests are a potent predictor of repeat DUI offences after the interlock is removed. The 15% of the sample that fails BAC tests at the highest rate are two-three times more likely to have a repeat DUI during the first 12 months after the interlock is removed.
Samenvatting