R v St-Onge Lamoureux: The Supreme Court of Canada upholds most of Parliament’s new “over 80” drunk driving law

On 2 November 2012, the Supreme Court of Canada (“SCC”) upheld the bulk of Parliament’s amendments to the “over 80” (ie., over .08 milligrams) drunk driving law in R v St-Onge Lamoureux, [2012] 3 SCR 187 [St-Onge]. Even before the 2008 amendments, s. 258 of the Criminal Code, RSC, 1985, c C-46 [Code] provided that breathalyzer results are presumed to be accurate. It also provided a presumption of identity, which means that breathalyzer results are presumed to actually reflect the blood alcohol content (“BAC”) of the accused at the time of the alleged offence.

To rebut these presumptions, an accused charged with having a BAC over .08 milligrams could raise a reasonable doubt by testifying about his or her alcohol consumption and producing a toxicologist report and toxicologist testimony that together indicated a lower BAC. Known as the “Carter defence,” this strategy lead to many acquittals despite the wide scientific acceptance of the accuracy of breathalyzer results.

Parliament has since enacted ss. 258(1)(c), 258(1)(d.01), and 258(1)(d.1), which together eliminate the Carter defence by introducing stringent requirements for an accused who wishes to rebut the above presumptions. St-Onge concerns a Charter challenge to these provisions alleging that they unjustifiably infringe ss. 7 (right to make full answer and defence), 11(c) (protection against self-incrimination), and 11(d) (presumption of innocence) of the Charter.

The impugned provisions

Section 258(1)(c) required that the accused must do the things to rebut the presumption of accuracy:

(1) raise a doubt that the instrument was functioning or was operated properly, (2) show that the malfunction or improper operation of the instrument resulted in the determination that his or her blood alcohol level exceeded the legal limit, and (3) show that his or her blood alcohol level would not in fact have exceeded that limit at the time when the offence was alleged to have been committed.

Section 258(1)(d.01) specifies the types of evidence that the accused cannot rely on to prove the above requirements, including: (1) the amount of alcohol the accused consumed, (2) the rate at which he or she consumed the alcohol or the rate at which his or her body eliminated it, and (3) a calculation based on these figures to determine what the accused’s BAC would have been at the time of the alleged offence. These forbidden types of evidence are essentially the evidence used in a Carter defence.

Rebutting the presumption of identity under s. 258(1)(d.1) is similarly stringent, requiring the accused to show that “his or her consumption of alcohol was consistent with both a … [BAC] not exceeding .08 at the time of the offence and with the results of the breathalyzer test.” (emphasis added)


Justice Deschamps writes the majority in this case, and Justices MacLachlin, LeBel, Fish, and Abella join her reasons.

Sections 258(1)(c) and 258(1)(d.01) infringe s. 11(d) of the Charter.

Justice Deschamps explains that a statutory presumption violates the right to be presumed innocent when it “exempts the prosecution from establishing the guilt of the accused beyond a reasonable doubt before the accused must respond….” Given that breathalyzers can malfunction and have their results skewed by human error, a trier of fact could entertain a reasonable doubt about the validity of the test results.

However, s. 258(1)(c) requires that the judge convict an accused who does not meet the above requirements for rebutting the presumptions of accuracy and identity despite this potential reasonable doubt. Given this potential for conviction even when a reasonable doubt exists, Justice Deschamps finds that the “mechanism for applying the statutory presumptions established in s. 258(1)(c)…infringe s. 11(d) of the Charter.”

Justice Abella then begins the Oakes analysis under s. 1 of the Charter by noting that the objective of the amendments is to give the results of breathalyzer tests an evidentiary weight consistent with their scientific value. She holds that this objective is pressing and substantial, and that the remaining stages of the Oakes test will be considered separately for each of the three requirements under s. 258(1)(c).

The first requirement under s. 258(1)(c), evidence of the malfunction or improper operation of the instrument, passes the rational connection and minimal impairment stages.

There is a rational connection between the objective and this requirement because the scientific evidence Parliament used to enact this requirement shows that the breathalyzer’s results should be accurate if it functions properly and its attendant procedures are followed. Justice Deschamps finds that it is logical to allow the accused to point out problems with the instrument or procedures that could skew the results.

Given that the “success rate of…[the Carter defence] is hard to justify in light of the scientific reliability of breathalyzers,” Justice Deschamps holds that the first requirement’s limitation to device or procedural failures is a minimal impairment because allowing evidence of consumption would force the prosecution to produce evidence of scientific reliability in every instance of the Carter defence. Given that the objective of s. 258(1)(c) is to recognize the scientific validity of breathalyzers, allowing Carter evidence would completely undermine Parliament’s objective.

Justice Deschamps postpones the proportionality analysis of the first requirement until she has completed the s. 1 analysis for the other two requirements.

The second requirement under s. 258(1)(c), the connection between the breathalyzer deficiency and the determination of a BAC exceeding .08, is not justified.

Showing that there is a causal connection between the malfunction or improper operation and the BAC reading constitutes a rational connection.

On the minimal impairment analysis, Justice Deschamps finds that this requirement is an excessive burden. Since s. 258(1)(d.01) limits the evidence that the accused can use to evidence that directly relates to the functioning or operation of the breathalyzer, discharging this burden would require expert evidence that is even more specific than that required under the first requirement.

Turning to the proportionality analysis, Justice Deschamps holds that this requirement “increases the burden on the defence significantly without reducing the expense to the prosecution.”

The prosecution need only produce expert evidence to refute the accused’s attempt to rebut the presumptions of accuracy and identity with expert evidence. Essentially, the second requirement imposes on the accused the initial burden of having to produce expert evidence to rebut the presumptions. Therefore, Justice Deschamps finds that the second requirement cannot be justified under s. 1 of the Charter.

The third requirement under s. 258(1)(c), evidence of a BAC not exceeding .08, is not justified.

Along with the first two requirements relating to breathalyzer malfunction or misuse, this requirement forces an accused to raise a reasonable doubt that their BAC exceeded .08. Given that the objective of the legislative scheme was to give breathalyzer test results a weight consistent with their scientific value and not to combat drinking and driving generally, Justice Deschamps holds that there is no rational connection between the stated objective and this measure.

The third requirement also fails at the minimal impairment stage. Since this requirement is in addition to the first two, an accused that does not demonstrate this requirement would have to be convicted even if they have already raised a reasonable doubt about the reliability of the BAC results. Therefore, Justice Deschamps holds that this is not a minimal impairment and that the third requirement cannot be justified under s. 1 of the Charter.

Once the second and third requirements are severed from the legislative scheme, the first can be justified under the proportionality analysis.

Justice Deschamps notes that the first requirement amendment was a response to the “serious disconnect that existed in the fact that the Carter defence had a high success rate despite the recognized scientific reliability of the results” of breathalyzer tests. In remedying this disconnect, Parliament also provided several limitations on police action in administering breathalyzer tests that protect the presumption of innocence. For example, a police officer must have reasonable grounds to suspect that a person has consumed alcohol before they can administer the test and the breath samples must be analyzed by a qualified technician using an approved instrument. Therefore, Justice Deschamps finds that the first requirement can be upheld under s. 1 of the Charter as a justified infringement of the s. 11(d) presumption of innocence.

Failed alternative constitutional challenges

The accused mounted several alternative constitutional challenges to the impugned provisions, but Justice Deschamps ruled in most cases that there was no infringement. In the case of s. 258(1)(d.1) (the presumption of identity), Justice Deschamps found that it did infringe the presumption of innocence in s. 11(d) of the Charter but that this infringement was justified under s. 1.


Justice Cromwell, who is joined by Justice Rothstein, wrote the dissenting opinion in this case. They find that the three requirements under s. 258(1)(c) and clarified by s. 258(1)(d.01) should be upheld.

So, what is the law now?

The majority preserved the bulk of the “over 80” drunk driving law in ss. 258(1)(c), 258(1)(d.01), and 258(1)(d.1) of the Code. The only parts of the law there were struck down were the second and third requirements under s. 258(1)(c). As it stands, the law still requires an accused to raise a reasonable doubt about the proper functioning or use of a breathalyzer to rebut the presumption of accuracy. The onus then shifts to the Crown, who can call experts or technicians to testify to the accuracy of the results. The rest of the statutory scheme, including the requirements for rebutting the presumption of identity in s. 258(1)(d.1), remains fully intact.

Carter no more

The real impact of this case is not the upholding of the provisions themselves but the SCC’s endorsement of their elimination of the Carter defence. The legislation requires that those accused of driving “over 80” must demonstrate a problem with the breathalyzer’s functionality or use without making recourse to any consumption or toxicological evidence (ie., Carter evidence).

This ruling represents the SCC’s formal acceptance of the scientific accuracy of breathalyzers. It does this by moving the locus of any defence to the “over 80” offence from the subjective testimony of the accused to the (arguably) scientifically objective world of breathalyzer functionality and procedure.

One potential benefit of the new legislative regime is that successful defences under the first requirement could spur more stringent police control and handling of breathalyzer devices. There was no similar incentive under the old regime that allowed Carter defences. Raising a reasonable doubt by means of a Carter defence shone a light on the accused’s testimony about his or her consumption, which implicated the breathalyzer results only indirectly.

By contrast, the new legislative regime requires that the accused raised a reasonable doubt about the test results specifically, without reference to his or her consumption. Successful defences under this regime will necessarily point out concrete problems with the device or how it was used. This could be useful information that could inform police practices and even technological refinement of the devices themselves. Whether this feedback materializes is yet to be seen, but it is clear that science has won this round at the SCC.

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