Alcohol Appears to Impair Driving More Than Cannabis
(HealthDay News) — Drinking alcohol appears to negatively affect driving skills to a greater extent than smoking cannabis, according to research findings published online June 23 in Drug and Alcohol Dependence. And, combined use leads to greater behind-the-wheel impairment, but it doesn't double the effect.
"What we saw was an additive effect, not a synergistic effect, when we put them together," study author Tim Brown, PhD, an associate research scientist who works with the University of Iowa's National Advanced Driving Simulator, said in a university news release. "You get what you expect if you take alcohol and cannabis and merge them together."
The team's simulated driving sessions involved 13 men and five women (between the ages of 21–37) and lasted between 35–45 minutes each. Apart from assessing the combined effect of both drugs when taken together, the team noted that alcohol on its own appears to lead to greater driving impairment than smoking cannabis on its own.
In fact, drunk drivers were found to have impaired driving skills on all three principal measures: weaving within a lane, leaving the lane entirely, and the speed of weaving, the researchers found. By contrast, the study found that those solely under the influence of vaporized cannabis displayed impairment only in terms of increased weaving within a lane.