Young Adult Driving Decisions: Appropriate for Alcohol but Not for Drugs

Introduction: For many years, public safety and media messages have been aimed at encouraging drivers not drink and drive. The success of this strategy is difficult to measure. There is substantial evidence from national surveys that young adults are aware of these messages but the extent to which they are influencing driving decisions is uncertain, particularly given the substantial number who report driving within two hour of drinking. Given their reported knowledge and concern with impaired driving but their continued driving after drinking there is great interest in the extent to which young adults have adopted safe-driving practices. Clubs that feature electronic music dance events (EMDEs) draw young adults in the high-risk age group of 18 to 34 years to locations where alcohol is the principal source of revenue, and up to 30% of the attendees may use drugs. We explored whether drivers were using less alcohol and drugs at exit than their passengers and whether the driver for the group ever changed when the driver over-consumed alcohol during the evening.

Methods: Using biological measures of alcohol consumption (breath tests) and drug use (oral fluid tests), 175 drivers and 272 passengers were surveyed among young adults arriving at and departing from EMDEs.

Results: Upon exit from the drinking locations, only 20% of the drivers, compared to 46% of the passengers, had a high blood alcohol concentration (defined as a BAC of .05 or greater). Further, 37% of the attendees who arrived as drivers and ended the evening at a high BAC switched to being a passenger and were replaced by former passengers with lower BACs. This resulted in a 25% overall reduction in the number of high BAC drivers leaving the EMDE. However, there were no differences in the prevalence of drug use among drivers and passengers. Most of the drug use occurred before arrival and there was no significant difference between passengers and drivers at either arrival or exit in the percentage using an illegal drug.

Conclusions: These findings suggest that impaired-driving enforcement and public information campaigns are influencing drinking-driving decisions, reducing driver BACs when compared to passengers by 50% from .053 to .025. However, there is no similar pattern for drugs. To date there has been relatively little information in the media relating to the risk of drugged driving and this study suggests it is reflected in the lack of a difference in drug use between drivers and passengers.