Officer Murchland

The Crown appealed an acquittal on a charge of operating a motor vehicle while impaired by a drug contrary to s. 253(1)(a) of the Criminal Code.

The trial judge had excluded both lay opinion evidence and expert evidence from police officers trained as Drug Recognition Experts (DREs), as well as a toxicology report, concluding that such evidence was inadmissible or failed to meet the Mohan criteria for expert evidence.

The appeal court held that lay witnesses, including police officers, may provide opinion evidence about impairment, and that trained DRE officers may give expert opinion evidence concerning drug impairment.

The court found that the trial judge erred in law by excluding the officers’ expert evidence and failing to consider the toxicology report.

As a result, the acquittal was set aside and a new trial was ordered.

The appellant appealed a summary conviction for impaired operation of a motor vehicle by drug under s. 253(1)(a) of the Criminal Code.

He argued that a toxicology report detecting only a cannabis metabolite (CO‑THC) and not the psychoactive component THC established that he could not have been impaired at the relevant time.

The court held that urine analysis was not determinative and did not necessarily exclude impairment, particularly where other evidence—including erratic driving, police observations, admissions of marijuana use, and a drug recognition expert’s evaluation—supported impairment.

The trial judge had properly weighed the toxicology evidence and was entitled to rely on the drug recognition evaluation and other observations.

No reversible error was found in the trial judge’s reasoning.