Rebutting The Breathalyzer Presumptions

In R. v. Cyr-Langlois,1 the Supreme Court of Canada offered clarification on the type of evidence that is required to rebut the presumptions of accuracy and identity applicable to breathalyzer test results under section 258(1)(c) of the Criminal Code ("Code").2 In doing so, Wagner C.J., writing for the majority, confirmed that the evidence must amount to more than conjecture or speculation. This case is significant for defence lawyers, as it demonstrates that an accused will likely need to adduce concrete factual evidence in order to rebut the breathalyzer presumptions.

Statutory Presumptions

Section 258(1)(c) of the Code contains two presumptions applicable to breathalyzer results: the presumptions of accuracy and identity. According to the presumption of accuracy, the certificate of the technician responsible for administering the breathalyzer test is presumed to provide an accurate determination of the person's blood alcohol level ("BAC") at the time that the breath samples were taken.3 According to the presumption of identity, a person's BAC as shown by the test results is presumed to be the same as his or her BAC at the time of the alleged offence.4 If an accused produces evidence that casts doubt on the reliability of the test results, the presumptions may be rebutted.

Facts and Case History

The accused, Marc Cyr-Langlois, was stopped by two police officers while driving. He was arrested at the scene and was taken to the police station. The accused received two breathalyzer tests at the police station. Both results were over the legal limit. The accused was then charged with operating a motor vehicle while impaired and operating a motor vehicle with a BAC exceeding 80 mg of alcohol in 100 ml of blood.

At trial before the Court of Québec, the accused argued that the qualified technician failed to observe him for a period of 15 or 20 minutes before administering each breathalyzer test. He submitted that this was a breach of the duty to operate the breathalyzer properly and that it was sufficient to rebut the presumptions of accuracy and identity applicable to breathalyzer results. The trial judge found that the fact that the procedure had not been followed was sufficient to raise a reasonable doubt as to the reliability of the results. The accused was therefore acquitted on the second charge, and the Crown had no evidence to adduce on the first charge.

The Crown appealed the trial judge's decision, and the Québec Superior Court set...