OTTAWA — A dispute over the admissibility of police “opinions” at drugged-driving trials lands at the Supreme Court of Canada Thursday in a case spotlighting an emerging legal dilemma over the hazy science of marijuana impairment.
With federal legislation to legalize recreational marijuana use expected next spring, the case of Carson Bingley of Ottawa could decide if, without a scientific standard, police officers’ opinions about whether motorists were high while driving should be automatically accepted as expert evidence at trial.
Unlike alcohol impairment, there is no legal blood-concentration driving limit for the active ingredients in marijuana and other drugs, nor is there an approved instrument for police to take readings that will be accepted in court.
A scientific advisory committee is reviewing the international literature to determine if there is consensus on appropriate blood-level limits for THC, the major psychoactive component of marijuana. But new research suggests a blood-cannabis concentration is not a reliable predictor of how impaired a person is.
This forces courts to rely on the opinions of police officers trained to spot drug impairment. But opinions are typically only allowed as evidence at criminal trials if they are made by qualified experts. The question of admissibility is usually decided during a voir dire hearing before the presiding judge.
The state’s concern is that requiring drug recognition evaluators (DREs) to submit to voir dires so they can testify will add delays and other complications to drug-impaired driving trials, which may dissuade police from pursing all but the more serious cases.
The competing concern is that personal opinions about drug-impairment levels, even from police, should not be legally acceptable in determining criminal guilt.
In 2009, Ottawa police charged Bingley with driving while impaired after he drove the wrong way and collided with a car. An arriving police officer said he showed signs of intoxication, but there was no smell of alcohol on his breath.
After an alcohol screening test found his blood-alcohol level was well below the legal limit, a police DRE administered a standard field sobriety test, which Bingley failed.
At a police station, he underwent a standardized 12-step drug evaluation. Bingley admitted to taking two Xanax and smoking half a gram of marijuana in the previous 12 hours.
Based on his admission and the results of the evaluation, the DRE decided his ability to drive was impaired by cannabis.
In provincial court, the judge admitted into evidence the DRE’s opinion as a “lay” opinion and dispensed with a voir dire.
The judge found that a 2008 section of the Criminal Code, introduced as part of the Harper Conservatives’ tough-on-crime legislative agenda, allows police DREs to automatically give expert opinions at impaired-driving trials, as they do in drunk driving cases.
Still, he acquitted Bingley, ruling there was a reasonable doubt about his guilt.
The provision’s actual wording, however, is not explicit and leaves open the question of whether Parliament intended DREs’ testimony to automatically be granted expert-opinion status – and evidentiary weight – by courts.
The Crown successfully appealed Bingley’s acquittal and a second trial was ordered.
But the new trial judge interpreted section 254 (3.1) differently and held a voir dire to determine whether to qualify the DRE as an expert witness. He later ruled the officer’s evidence was inadmissible and Bingley was once again acquitted.
The Crown appealed to the Ontario Court of Appeal, which found the police officer’s opinion was admissible under section 254 (3.1). Bingley was later granted leave to appeal to the Supreme Court.