Research team explores risks of driving while stoned

A sobering debate could be one step closer to resolution, thanks to a University of Victoria professor and a research team that aims to measure how being high affects a person’s ability to drive.

Dr. Scott Macdonald is investigating how pot impairs.

Dr. Scott Macdonald is investigating how pot impairs.

A sobering debate could be one step closer to resolution, thanks to a University of Victoria professor and a research team that aims to measure how being high affects a person’s ability to drive.

While it may sound like common sense, Canada has never performed a comprehensive study to conclude that THC, the active ingredient in marijuana, impairs driving skills.

A similar study was conducted by an Australian researcher for fatally-injured drivers, which found those with active THC in their blood were significantly more likely to be responsible for their crashes. However, B.C.’s multicentre culpability study will be a first of its kind in Canada. The research team will work with five hospitals throughout the province to utilize blood sampling, the most accurate form of THC detection.

“We know from lab studies that cannabis impairs performance, but we know people also drive with real-world conditions and this study looks at the risks actually involved with that impairment,” says Dr. Scott Macdonald, a professor and scientist out of UVic, and the assistant director for the Centre of Addictions Research. “To date, this will be the most methodologically sound study done of its kind in the world.”

The researchers hope to study more than 3,000 subjects over a period of five years and will utilize a portion of the blood samples taken from people in accidents who already had to consent to blood work. This, Macdonald says, is the only way to ensure no bias in lab results, since many people — even a control group — would not voluntarily submit to something as invasive as blood sampling. However, as opposed to urine, saliva or hair samples, which can indicate the presence of THC days or months ago, a blood test remains the most accurate way to register the exact THC levels at the time of a crash.

“I feel good about this study; we see a lot of research attempted on cannabis, but there are so many flaws in the methodology that we’re just getting conflicting information,” says Macdonald. “There is a lot of mythology out there about the risks of driving impaired.”

In addition to Macdonald, who has spent the last 25 years researching the epidemiology of drugs and impairment, the team includes emergency care physicians from Vancouver, University of British Columbia scientists and the researcher who headed the Australian study. A pilot project, which involved over 100 subjects, was recently completed and used to help secure funding for this million-dollar study.

The team will be examining four different control groups, ranging from a level of 1, with little or no THC in the blood, to over 3.5, which indicates a level of severe intoxication. While it’s hard to compare between the two, Macdonald suggests that a THC level of 3.5 could be equivalent to a blood-alcohol level of 0.1 — significantly over the limit.

Currently, in B.C., the legal blood alcohol limit is 0.05, with anything above 0.08 falling into the criminal category. While many people round that off to a grey safety zone of about one drink per hour, it’s more challenging to know how many puffs would do a person in. Like alcohol, pot impacts each body differently and, until more research is done, Macdonald says we may be in the dark on a lot of answers.

“Hopefully, this will help to increase awareness,” he says. “Many people believe there is no risk, or that they can compensate by driving slower, but people used to say that about alcohol, too.” M

Just Posted

It takes much more than having talent as a singer or musician to pull off a live performance people will remember, says Sooke resident Jason Parsons. (Pixabay.com)
Vancouver Islander writes the book on live performances

Jason Parsons’ new book unlocks the keys to establishing a presence on stage

VIU’s ‘Portal’ magazine is turning 30 years old. (Image courtesy Chantelle Calitz)
Vancouver Island University’s literary magazine ‘Portal’ celebrates 30 years

Virtual launch featuring contributor readings took place April 30

Nanaimo author Haley Healey recently launched her second book, ‘Flourishing and Free: More Stories of Trailblazing Women of Vancouver Island.’ (Photo courtesy Kristin Wenberg)
Nanaimo author pens second book on ‘trailblazing’ Vancouver Island women

Haley Healey’s ‘Flourishing and Free’ follows her 2020 debut ‘On Their Own Terms’

Saanich author Hannalora Leavitt hopes her new book, This Disability Experience, helps to dispel the ‘otherness’ that often surrounds people with disabilities. (Jane Skrypnek/News Staff)
Vancouver Island author demystifying disability and dismantling otherness

Hannalora Leavitt, who lives with a visual impairment, wants to change how people look at disability

The organizers of the annual 39 days of July festival hope to return to live shows in Charles Hoey Park this year, like in this photo taken in 2019, but audiences at the show may be limited to 50 people due to health protocols. (File photo)
39 Days of July hoping to stage outdoor events in Duncan this summer

Annual music festival will run from June 25 to Aug. 2 this year

Members of A Cappella Plus rehearse for a ’60s-themed concert in 2019. This year the group is celebrating its 40th anniversary. (Bulletin file photo)
Nanaimo’s A Cappella Plus chorus marks 40 years with short documentary

Film covers group’s history, features performance and behind-the-scenes video

Musqueam and Qualicum First Nations artist, Mathew Andreatta, next to several of his ongoing projects, including carvings and illustrations. (Submitted photo)
Island artist considers art a means to reconnect with his Indigenous identity

Andreatta thought of TOSH as a space of learning and creation

Nicolle Nattrass and Michael Armstrong are presenting an online reading on May 9. (Photos courtesy Joni Marcolin/Heather Armstrong)
Nanaimo playwrights present online Mother’s Day script readings

Nicolle Nattrass and Michael Armstrong to read from in-progress plays

Marianne Turley is one of this year’s City of Nanaimo Culture and Heritage Award winners for Honour in Culture. (Bulletin file photo)
Longtime Vancouver Island Symphony board member gets posthumous culture award

Marianne Turley receives City of Nanaimo Culture and Heritage Award for Honour in Culture

Most Read