Impaired driving laws lag behind as cannabis legalization draws closer

Jun 9 2018, 12:59 am

The Senate passes Bill C-45, which means that cannabis legalization is in sight for Canadians.

As a companion to the Cannabis Act, the government has proposed Bill C-46, which deals with impaired driving.

Bill C-46 addresses both alcohol and drug-related impairment behind the wheel, but it’s the latter that has some experts worried.

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“The disturbing thing to me is the government passing per se limits with cannabis,” said criminal defense lawyer Sarah Leamon, who reached out to Daily Hive.

Per se limits are a standardized measure of intoxication. For alcohol, the limit is 80 milligrams of alcohol in 100 millilitres of blood. Bill C-46 would make it an indictable offence to have more than five nanograms of THC per milliliter of blood, and a ticketable offence for lower concentrations.

“With alcohol, we can say a person is impaired when they reach a certain level,” said Leamon. “A person doesn’t have to be displaying that they’re impaired; if they have that amount of alcohol in their bloodstream then they are.”

Leamon said that there “is no correlation between levels of THC in system and impairment,” a concern that is echoed by Dr. Tony George, a researcher at CAMH and professor at the University of Toronto.

“I’m puzzled, as a scientist,” Dr. George told Daily Hive over the phone in April.

“I don’t understand how this framework is [quantifying] impairment when I’m saying clinically if we can’t detect cannabis in someone’s urine at levels at less than 20, we call that abstinence.”

Dr. George said that one of the issues with reliable roadside testing is that people develop a tolerance to cannabis, and of equal concern is that you can test positive for THC even if you’re sober.

THC is fat soluble and therefore stays in your body for much longer than alcohol, which can dissipate in hours.

The long-acting metabolite carboxy THC is what gets measured via blood, saliva, or urine, and that can take “a month to wash out of someone’s system if you’re a regular user,” said Dr. George.

Evidence from the US says we are still 10-15 years away from a reliable roadside test, “yet our government claims to have this all figured out.”

Leamon said that law enforcement may use a saliva swab test, but she sees that as “junk science.”

Another concern for Canadian law enforcement is that oral fluid roadside testing only works in certain ambient temperatures, limiting its use in colder climates. And again, the lack of a meaningful correlation between impairment and per se levels remains a problem.

The RCMP, in consultation with police services across Canada, has developed a new “Introduction to Drug-Impaired Driving” training curriculum for Canadian law enforcement to complement current Standard Field Sobriety Testing (SFST) training.

The course is taken in person and includes training on the signs and symptoms of drug impairment found in drivers, with a special emphasis on cannabis.

The problem with this test is that it’s subjective, and Leamon said there are only about 200 drug recognition experts in Canada.

“What they are working towards is a roadside brain imaging test,” said Dr. George. The equipment will cost tens of thousands of dollars and will need to be taken around in a trailer, which seems like a rather inconvenient solution.

Leamon believes that charges arising from cannabis-impaired driving “could be successfully challenged,” and expects to see issue in the courts.

DH Vancouver StaffDH Vancouver Staff

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