OTTAWA - The Supreme Court of Canada has affirmed impaired driving convictions in two significant cases. The court ruled that amendments to criminal law made in 2018 aimed to simplify the prosecution process for cases relying on breath test results.

The decisions, announced on Friday, clarify the standards for proving blood alcohol concentration under the Criminal Code. The Supreme Court evaluated whether the New Brunswick Court of Appeal made errors in its interpretation of the evidence required for the Crown to establish the accuracy of breath test results.

According to the law, breathalyzer machines must undergo calibration checks, and the results must fall within a specified range. In one of the cases, the court focused on the evidence necessary to demonstrate that a breath machine had successfully completed a calibration check. In the other case, the court examined the requirements for using breath test results as evidence in court.

These rulings are expected to have a significant impact on future impaired driving cases, reinforcing the legal framework surrounding breathalyzer evidence. The Supreme Court's decisions provide clarity on the evidentiary requirements that must be met to uphold convictions based on breath test results.

This report was first published on November 14, 2025.