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Evidential Breath Testing for Alcohol: Parliament, the Science and the Courts

NCJ Number
Canadian Society of Forensic Science Journal Volume: 46 Issue: 1 Dated: March 2013 Pages: 59-78
Greg Yost
Date Published
March 2013
20 pages
This paper reviews the scientific evidence presented to parliamentarians as they amended the Criminal Code to provide a scientific basis for assessing impairment by alcohol.
In 1951, the Criminal Code provided for the admissibility of evidence from breath testing for alcohol. Since 1969, it has been an offense to drive with a blood alcohol concentration (BAC) exceeding 80 mg of alcohol per 100 mL of blood ("over 80" or "over .08"). The primary means of determining BAC is breath testing, and members of Parliament considered the accuracy of the "Breathalyzer" in 1966. Parliament has on several occasions amended the legislation in an effort to make it more effective in protecting the public. Most recently in the Tackling Violent Crime Act (TVCA), S.C. 2008, c.6, Parliament reconsidered the science behind breath testing and amended the legislation to restrict "evidence to the contrary." The TVCA amendments provided that low consumption evidence by itself is not sufficient to raise a reasonable doubt of the accuracy of the approved instrument (AI) analysis of BAC. The amendments specified that evidence of the amount of alcohol consumed, the rate at which alcohol was absorbed and eliminated, and a calculation of the hypothetical BAC of the accused based on that evidence was not evidence of AI malfunction or improper operation. The Supreme Court of Canada heard a challenge to the constitutionality of the scheme on October 13, 2011, and released its judgment on November 2, 2012 in R. v. St-Onge Lamoureux, 2012 SCC 57. The Supreme Court unanimously held that evidence of consumption was not sufficient to raise a reasonable doubt in the absence of evidence of instrument malfunction or operator error. (Published Abstract)