Case in Brief

A Case in Brief is a short summary of a written decision of the Court, drafted in plain language. These summaries are prepared by staff of the Supreme Court of Canada. They do not form part of the Court’s reasons for judgment and are not for use in legal proceedings.

R. v. Rousselle

Case summary

The Supreme Court of Canada rules that the Crown can rely on a certificate from the person administering a breath test to prove that the breath machine is properly calibrated.

This appeal is about what the Crown must prove to rely on breath test results in a drunk driving case. The courts presume that the results are accurate if certain conditions are met. This is called the “presumption of accuracy”. When the conditions are met, the results can be used as strong proof of a person’s blood alcohol level at the time of testing.

One condition is that the breath machine must pass a system calibration check before testing. The check uses an alcohol standard, which is a solution with a known amount of alcohol. The known value is certified by an analyst before the alcohol standard is installed in the breath test machine. The analyst’s role is to certify the known alcohol value of the standard whereas the qualified technician performs the calibration check on the breath machine. If the machine is working properly, its calibration result should match that known value. To pass the check, a qualified technician must certify that the results are within 10% of the known value. The question for the Court was whether the Crown could rely only on a certificate from the person administering the breath test (a qualified technician) to prove the breath machine passed the calibration check, or if evidence from the analyst is required.

When stopped by police, Mr. Rousselle provided two breath samples that showed a blood alcohol concentration above the legal limit. He was charged with drunk driving.

At trial, the Crown relied on the qualified technician’s certificate to prove that the breath test had been done properly. The trial judge decided the Crown had not proven that the alcohol standard used in the system calibration check was certified by an analyst and found Mr. Rousselle not guilty. The summary conviction appeal judge (a higher-level judge) later overturned that decision and entered a conviction. The Court of Appeal agreed. Mr. Rousselle then appealed to the Supreme Court.

The Supreme Court dismissed the appeal.

The qualified technician’s certificate is enough to prove that the alcohol standard was “certified by an analyst”.

Writing for the majority, Justices Rowe and Moreau said the Crown can prove that the alcohol standard used in the system calibration check was certified by an analyst through the evidence of the qualified technician, including by certificate.

Justices Rowe and Moreau explained that the objective of section 320.32(1) of the Criminal Code is to make impaired-driving cases simple and efficient. Section 320.32(1) says a certificate is “evidence of the facts alleged”, which supports using the qualified technician’s certificate to show that the alcohol standard used in the system calibration check had been certified by an analyst. An accused can still challenge the certificate by pointing to problems or questioning the technician.

For these reasons, Mr. Rousselle’s conviction was maintained.