R. v. Starn
10 C.C.C. (3d) 363
At trial, the accused presented expert witnesses who testified that the breathalyser machine, a Borkenstein Model 900A, was calibrated to the mathematical equation that 2100 millilitres of lung air is equal to the alcohol concentration in 1 milligram of blood. The experts further testified that the subject had a lower ratio and therefore the breathalyser would �over-read� the accused. At trial it was found that this was not evidence to the contrary and the accused was convicted. Upon appeal to County Court is was found that it is evidence to the contrary and the accused was acquitted.
Even if it is accepted that the accused had a lower ratio then the breathalyser tested for, the accused would have still been over the legal limit of 80 milligrams in 100 millilitres of blood. Physical abnormalities in the ratio of an individual are irrelevant unless it can be proven that the blood-alcohol level of the accused was within the legal limit at the time of the offence. In this case, the experts could not give with 100% certainty the ratio of the accused at the time of the offence. As a result, their evidence does not constitute evidence to the contrary as it does not prove, or show to prove, that the blood alcohol level of the accused was within the legal limit at the time of the offence.