Skip to main content

The Globe and Mail

Supreme Court ratifies police as experts in drug-impaired driving trials

The Supreme Court of Canada in Ottawa on June 8, 2016.

Blair Gable/The Globe and Mail

Police officers trained to recognize if drivers are high can be treated as experts in drugged-driving trials without a preliminary examination of the evidence, the Supreme Court has ruled in a decision that could help expedite such prosecutions once marijuana is eventually legalized.

The 5-2 decision in the case of an Ottawa motorist comes as the federal Liberal government prepares to bring in a law legalizing the recreational use of pot this spring, with a rise in cannabis-impaired driving singled out as a key risk to public safety.

"Driving while impaired by drugs is a dangerous and, sadly, common activity, prohibited by the Criminal Code," Chief Justice Beverley McLachlin wrote in her reasons for the majority decision.

Story continues below advertisement

"Parliament long ago established a regime to enforce the law against alcohol-impaired driving, with breathalyzer testing and analyst certification at its centre. Enforcing the offence of drug-impaired driving was more elusive."

In 2008, Ottawa introduced a 12-part evaluation for drug impairment, established through regulations, to be administered by police officers who receive special training and certification – so-called "drug-recognition experts."

There are of 500 active Mounties have undergone such training, which represents about a third of all police officers trained as experts across the country, an RCMP spokesperson confirmed.

Thursday's ruling centres on the May, 2009 case of Carson Bingley, who cut off a driver, drove across the centre line and into the opposite lane, nearly striking oncoming traffic before bumping into a car in a nearby parking lot. After the crash, he failed sobriety tests administered by a drug-recognition expert and admitted to smoking marijuana.

Mr. Bingley was acquitted of driving while drug impaired despite the expert's evidence, which the judge at the time found could be admitted without a voir dire, or preliminary examination of the evidence.

An appeal led to a second trial, where a judge found that the evidence must be vetted in a voir dire. The subsequent preliminary examination led the judge to rule the expert evidence inadmissible, resulting in a second acquittal. The Crown successfully appealed and a third trial was ordered; Thursday's Supreme Court ruling means that trial will go ahead.

The Criminal Code allows police to compel a person to submit to a drug-recognition evaluation when there are reasonable grounds to believe the individual has been driving while impaired by drugs. The 12-step procedure includes eye evaluations, attention tests and measurements of blood pressure, temperature, pulse and muscle tone. If the evaluation leads the officer to further believe the person is impaired by a drug, the officer can then take tests of saliva, urine or blood to determine whether the driver has drugs in their system.

Story continues below advertisement

The Supreme Court ruled that a drug-recognition expert has expertise beyond the knowledge and experience of a trial judge under the system set out in law. Ms. McLachlin said that holding a trial within a trial to evaluate each officer's admissibility as an expert would be "a waste of judicial resources."

Still, under the current system of enforcement, it can be difficult for police to get cannabis-impaired driving charges to stick because there are no reliable roadside tests. Several are still in their pilot stages, and researchers are still trying to determine how, and at what level, marijuana affects drivers.

A Saskatchewan Provincial Court ruling in August, 2012, decided that police at a roadside check could not prove a woman was impaired from a joint she admitted to smoking 2 1/2 hours earlier. That was despite her failing several field sobriety tests – such as walking in a straight line and touching her nose – and being given a blood test at the police station that was positive for THC. The judge stated that there was no doubt the accused had used the drug before getting in her car, but there was no proof that it negatively affected her performance behind the wheel.

With a report from The Canadian Press

Report an error Licensing Options
About the Author
News reporter

Mike Hager is a general assignment reporter at the newspaper’s B.C. bureau. He grew up in Vancouver and graduated from the University of Western Ontario’s Huron College and Langara College. Before joining The Globe and Mail, he spent three years working for The Vancouver Sun. More


The Globe invites you to share your views. Please stay on topic and be respectful to everyone. For more information on our commenting policies and how our community-based moderation works, please read our Community Guidelines and our Terms and Conditions.

We’ve made some technical updates to our commenting software. If you are experiencing any issues posting comments, simply log out and log back in.

Discussion loading… ✨

Combined Shape Created with Sketch.

Combined Shape Created with Sketch.

Thank you!

You are now subscribed to the newsletter at

You can unsubscribe from this newsletter or Globe promotions at any time by clicking the link at the bottom of the newsletter, or by emailing us at