The accused was charged with driving with a blood alcohol level exceeding 80 milligrams.
At trial, the Crown introduced a certificate of analysis from a breathalyzer test.
The defence called an expert witness who testified that the technician's failure to record the room temperature during the calibration check could result in an inaccurate reading.
The trial judge acquitted the accused, and the acquittal was upheld on appeal.
The Supreme Court of Canada allowed the Crown's appeal, holding that the certificate was admissible and that the expert's testimony regarding a mere possibility of inaccuracy did not constitute 'evidence to the contrary' sufficient to raise a reasonable doubt.
