The Supreme Court upheld key provisions in the 2009 Criminal Code amendments. These amendments were designed to eliminate the so-called “two-beer defence”, also known as the “Carter defence” and “evidence to the contrary.” Before 2009, the “two-beer” defence was an effective defence argument that had resulted in many acquittals.

This recent decision does, however, strike down an onerous provision which required defendants to show precisely how a malfunctioning or improperly operated Breathalyzer caused an Over 80 reading. As a result, criminal lawyers will again be able to argue that Breathalyzyer machines are not infallible.

The “two-beer” defence before the 2009 amendments

Using the “two-beer” defence, a defendant typically testified that he had only consumed a couple of drinks before driving. The defence would then produce a toxicology expert to testify that the defendant’s blood alcohol content was below 80 mg%. Such testimony often caused judges to conclude that the Breathalyzer malfunctioned or had been operated improperly (or more accurately, the judge had a reasonable doubt that the machine was accurate).

The “two-beer” defence was allowed even though there was no evidence that the Intoxilyzer machine was inaccurate, aside from the defendant’s testimony regarding the amount he drank. Critics argued that self-reported drinking patterns were inaccurate, while Breathalyzers were highly reliable.

The elimination of the two-beer defence in 2009

The 2009 amendments to the Criminal Code virtually eliminated the two-beer defence by effectively deeming Breathalyzers to be infallible. The 2009 amendments imposed an impossible burden on defendants by requiring them to show all of the following:

(1) that the breath-machine was malfunctioning or was operated improperly;

(2) that the malfunction or improper operation of the breath-machine resulted in the determination that his blood alcohol level exceeded 80 mg%; and,

(3) that his blood alcohol level would not in fact have exceeded that limit at the time when the offence was alleged to have been committed.

Requiring a defendant to show that a malfunction caused the breath-reading to be over 80 mg% imposed an impossible hurdle on accused persons. For example, even if a defendant had a video-recording of them not drinking any alcohol over the course of a night, that would not satisfy the 2009 amendments. The machine was deemed to be accurate. The innocent accused would be found guilty due to the amendments.

The Supreme Court of Canada’s fine-tuning of the drinking and driving amendments

The Supreme Court decision in St. Onge Lamoureux eliminates the second and third parts of the above 2009 amendments; the Supreme Court ruled that these requirements violated the presumption of innocence. Now, an accused person only has to show that the Breathalyzer was malfunctioning or was operated improperly.

The impact of the Supreme Court decision on impaired driving cases

The Supreme Court’s decision will likely impact drinking and driving cases in two main ways.

First, if a defendant raises a doubt that that the breath-testing machine malfunctioned, the prosecution will not be able to rely on the accuracy of the breath-readings. To get a conviction, the prosecution will therefore need a toxicology expert to calculate the defendant’s blood alcohol level. In practice, this will usually result in an acquittal, because the prosecution will not be ready with a toxicologist at the trial.

Second, this decision will likely lead to police and prosecutors having to routinely produce records of breathalyzer maintenance records and the credentials of their operators. The Supreme Court stated:

Although Parliament now requires evidence tending to establish a deficiency in the functioning or operation of the instrument, this does not mean that there are limits on the evidence that can reasonably be used by the accused to raise a doubt in this regard. The accused can request the disclosure of any relevant evidence that is reasonably available in order to be able to present a real defence. If the prosecution denies such a request, the accused can invoke the rules on non‑disclosure and the available remedies for non‑disclosure. In short, the accused might rely, for example, on a maintenance log that shows that the instrument was not maintained properly or on admissions by the technician that there had been erratic results, or he or she might argue that health problems had affected the functioning of the instrument.

As a result, technical disclosure applications will continue to play an important role in defending drinking and driving cases in Ontario.