A 1% sample of Michigan drivers, with 68,950 drivers and 180,423 incidents, was drawn in June, 1982. A subset of drivers with alcohol-related (a-r) accidents, convictions for DUIL or DWI offenses, or breath-test refusals under implied-consent legislation was created. If an accident and a conviction of IC refusal occurred on the same date, only the accident was retained. The resulting file had 4,649 drivers with 3,589 HBD (Had Been Drinking) accidents, 2,834 DUIL/DWI convictions, and 155 IC refusals. A two-way distribution showed that, of drivers having either a-r accidents or drunk-driving (d-d) offenses, only 13.2% had both. Further, if the occurrence of either triggers a countermeasure based on specific deterrence, the maximum percentage of HBD accidents preventable by a 100% effective program is 35.9%. This finding led to the conclusion that countermeasure programs relying on general deterrence must be used to reach the majority of potential drivers in a-r accidents. The risk of a driver having a subsequent a-r accident was also determined. The occurrence of either a non-accident, d-d offense or the occurrence of an a-r accident elevates the risk of a subsequent accident by a minimum factor of 3.5. The elevated risk makes such drivers candidates for countermeasures based on principles of specific deterrence.
Abstract