R. v. Gibson

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Link to the original Supreme Court decision (April 17, 2008).

Case summary: Two drivers, G and M, were arrested for driving with blood alcohol over 80mg/dL. G gave two breathalyzer samples with results of 120 and 100. M gave two samples both tested at 146. At trial they presented evidence from experts that based on more accurate analysis, G's blood alcohol would have been between 40 and 105, and M's would have been between 64 and 109. Also, the existing breathalyzer system is based on an unrealistic assumption that people eliminate alcohol at 15mg/dL/hr, while the average is higher, thus the breathalyzer tends to read too high. Also, an expert tested M's elimination rate more than six months after the arrest, found it to be 18.5, and estimated based on that that his blood alcohol level at the time of the arrest would have been 71. G was acquitted at trial on reasonable doubt that his blood alcohol had been over 80; then the appeals court set aside the acquittal on the grounds that "evidence of a hypothetical person's elimination rates was not capable of rebutting the presumption in s. 258(1)(d.1)" (which says that blowing over 80 on the breathalyzer can be sufficient to prove that blood alcohol is over 80) and ordered a new trial. M was convicted for lack of reasonable doubt and two appeals courts upheld the conviction.

Opinions:

(Bastarache, Abella, Charron, and Rothstein): The crime of drunk driving is not really about having a blood alcohol level over 80, but about getting drunk enough to put one's blood alcohol level over 80. The expert evidence makes clear that both accused did get that drunk, because their blood alcohol ranges included values over the limit. Also, people's alcohol elimination rates vary dramatically over time and conditions. The elimination test taken by M more than six months after the arrest proves nothing about his body's elimination rate at the time of the arrest; and since taking such a test requires the tested person to drink alcohol, and drunk-driving accused are often recovering alcoholics who should not drink, it would be bad policy to create an incentive for them to drink by accepting that kind of evidence. In general, the court should not accept this kind of evidence showing the accused's blood alcohol was in a range straddling the limit. The lower-court results stand. Majority decision.

(McLachlin, LeBel, and Fish): This kind of evidence could in principle be accepted if it were very strong, and it would be unfair to categorically deny defendants the right to use it, but "[s]traddle evidence will rarely suffice on its own to raise a reasonable doubt as to the accuracy of a breathalyzer result[.]" In particular, a wide range straddling the legal limit proves very little, and an elimination test would have to be very well-controlled to provide meaningful results. So although straddle evidence in general might be acceptable, this particular straddle evidence is not strong enough to raise reasonable doubt that the breathalyzer is accurate, and the lower-court results stand.

(Binnie and Deschamps): All the evidence should be considered, and a decision made based on the "prevailing direction" of the range. In G's case that supports the acquittal. In M's case it does not, but the trial judge made other errors in discounting the expert's evidence inappropriately, and since we do not have the power to acquit M at this level, we would order a new trial for him.