The risk of being in a collision increases even five hours after a young driver has used marijuana, according to researchers at McGill University.
In a clinical trial funded by the Canadian Automobiles Association, researchers at the Research Institute of the McGill University Health Centre and McGill University found that the performance of young drivers in areas like reaction time declined significantly even five hours after the inhalation of the equivalent of less than the amount of pot in one typical joint. The study involved putting drivers between the ages of 18 and 24 in driving simulators after they had consumed 100mg of marijuana, using a vaporizer.
Polling done by the CAA has suggested that 20 per cent of young Canadians believe they are just as good or better behind the wheel after consuming pot.
The study showed that, when the drivers were not subjected to any distractions, their performance was similar to when they had no cannabis in their system. However, when they were subjected to distractions, their performance saw a significant reduction in quality, even several hours after they had used marijuana.
"This rigorous experimental trial adds to a growing body of scientific literature on cannabis use and driving," said study co-author Isabelle Gélinas, a researcher in McGill's School of Physical and Occupational Therapy. "The findings provide new evidence on the extent to which driving-related performance is compromised following a typical dose of inhaled cannabis, even at five hours after use."
The peer-reviewed study was published online CMAJ Open, an online sister journal to the Canadian Medical Association Journal.