Approximately 2500 teens were surveyed each year, over a three year period. Each year, tenth grade students were asked how many times they had ridden with a driver who had been drinking or taking drugs in the past year. They were then asked how long they had a driver's license, questions pertaining to the use of drugs and alcohol, and about whether their parents were aware of their choices. In the final year of the study, students were asked how many times in the past 30 days they had driven after using drugs or alcohol.
The study found that students who had ridden with someone who had been drinking or using drugs were eleven times more likely to decide to drink and drive themselves. In some respects, this makes sense. Drinking and driving education for teenagers often focusses on the devastating social consequences of that behaviour: the likelihood of an accident, death, or injury. Individuals who do not experience these consequences are probably more likely to consider them more remote, and to engage in risk-taking behaviour themselves.
Interestingly, students who got their driver's licenses earlier were also nearly two times more likely to drive drunk than those who got their licenses later. At least 30% of the students surveyed had either ridden with a drunk driver or had driven drunk themselves.
Studies like this are important. They help to understand why drunk driving incidents occur, so that prevention efforts can be aimed at methods that are more likely to produce success. In British Columbia, the Immediate Roadside Prohibition regime is said to have saved lives by preventing drinking and driving. However, studies have also shown that younger drivers are more likely to drink and drive, meaning that an aging population in British Columbia would cut down deaths. And despite the fact that IRPs are said to have saved lives, impaired driving is still on the rise in British Columbia, according to Stats Canada. But that's another blog post for another day.