In cases involving scientific measurements, the margin of error must be accounted for: court
The Ontario Superior Court of Justice dismissed charges against a defendant accused of driving with over 5 ng/mL of THC, ruling that the Crown failed to prove beyond a reasonable doubt that the THC level met the legal limit due to the margin of uncertainty in the expert's evidence.
The defendant faced four charges: two counts of dangerous operation of a vehicle causing death and bodily harm and two counts of operating a vehicle with over 5 ng/mL of THC in his system. While the dangerous operation charges were not the subject of this application, the defendant sought a directed verdict of acquittal on the THC-related charges, arguing the evidence did not support a conviction.
The case stemmed from a February 2021 collision in Kitchener, Ontario, where the defendant’s vehicle struck another car, resulting in the death of a passenger and injuries to the driver. The Crown’s expert, a forensic toxicologist, testified that the THC concentration in the defendant’s blood was 5.2 ng/mL, but due to the margin of uncertainty, the level could have been as low as 4.8 ng/mL. This uncertainty led the court to consider whether the THC level was definitively above the legal limit of 5 ng/mL.
Defence counsel argued that because the THC level could have been below the legal threshold, a reasonable jury could not convict the defendant beyond a reasonable doubt. The Superior Court agreed, noting that the possibility of a THC level below 5 ng/mL created reasonable doubt about the defendant's guilt.
The Crown’s case relied on circumstantial evidence, but the court emphasized that in cases involving scientific measurements, the margin of error must be accounted for. The court concluded that the evidence did not meet the legal standard of proof required for conviction and dismissed the charges related to THC impairment.
The dangerous operation charges remain pending as the case proceeds.
