While many say alcohol impairment is worse than cannabis impairment, researcher Scott MacDonald says both increase the likelihood of fatal crashes when driving, with alcohol still being the most dangerous drug on the road.
New laws came into effect Tuesday allowing police officers to collect a breath sample from any driver that has been lawfully stopped, without requiring the suspicion that the person has been drinking.
However, there needs to be more research around cannabis and driving, said MacDonald, a scientist with UVic’s Canadian Institute for Substance Use Research who has focused his career on research issues in the field of substance use including impaired driving laws, the role of substance use in injuries, program evaluation, and cannabis and alcohol policy.
Until studies show differently, alcohol is the most dangerous drug on the road, he said.
“There’s been less studies on the effects of cannabis than alcohol because cannabis was illegal,” MacDonald said. “Cannabis impairment is associated with increased likelihood of fatal crashes with a large scale study in Australia.”
The top three driving factors that led to B.C. fatalities in 2017 were speed (70), impairment (70), and distracted driving (73).
With cannabis legalization comes a new era, some of which MacDonald captures in his new book, Cannabis Crashes: Myths & Truths, a research-based text for students, policy makers, lawyers and experts in the field of substance use and crashes.
“One of the problems is the rate at which THC [tetrahydrocannabinol] passes through the system,” MacDonald said.
In some users it can pass through in a day, while in others, it can hang around for a week, he added. This could – and likely will – create challenges in tracking cannabis impairment if a driver is guilty of causing a motor vehicle incident and tests positive for levels of THC, but is actually sober.
In anticipation of new drunk driving laws and a potential increase in cannabis impairment on the road, MacDonald visited DriveWise B.C.’s Saanich office to experience the driving simulator, without having to ingest either.
The simulator can create a multitude of scenarios and conditions but is also not meant to replace what actually happens on the road, said Kate Wells, operations manager for DriveWise B.C.
Rather, it is to create scenarios so that drivers new and old can learn how to prepare themselves in case they do encounter those situations, she said.
Wearing adapted ski goggles that intentionally blur your vision and depth perception, Wells began driving the machine while MacDonald talked about what impairment symptoms lead to crashes. Mostly weaving, slower reaction times and fatigue, including falling asleep at the wheel, all from high blood alcohol concentrations.
– With files from Keri Coles