Cannabis & Drug-Impaired Driving in Ontario

The federal per se THC limits

Canada's Criminal Code sets out specific blood-THC concentration thresholds that are offences on their own, regardless of whether a driver otherwise appears impaired. A concentration of 2 nanograms of THC per millilitre of blood supports a lower-tier, summary-conviction offence. A concentration of 5 ng/mL or more supports a more serious offence. A separate, combined-impairment offence applies where a driver has at least 2.5 ng/mL of THC along with any detectable blood alcohol concentration at the same time.

Roadside oral fluid screening

Where an officer has a reasonable suspicion that a driver has a drug in their body -- based on objective signs observed during a stop -- they can demand a roadside oral fluid sample using an approved screening device. A positive result on this kind of screener is a preliminary indicator, not proof of impairment on its own, but it can support further testing and an immediate licence consequence.

Zero tolerance for novice and commercial drivers

Since July 1, 2018, Ontario has applied a zero-tolerance standard for drug presence to novice drivers -- those holding a G1, G2, M1, or M2 licence -- and to commercial drivers, regardless of age. Under this standard, any detectable presence of drugs picked up by an approved screening device can trigger a consequence for these drivers, a stricter standard than what applies to a fully licensed driver outside these categories. A medical cannabis authorization doesn't remove this standard on its own.

Two separate consequence systems

It's worth understanding that a Criminal Code charge and an Ontario Highway Traffic Act licence suspension are two distinct, parallel systems. The administrative suspension is an immediate, roadside licensing consequence that can apply even before -- or separately from -- any criminal charge proceeding through the courts. Because the specific suspension lengths and any associated fines can depend on the exact circumstances and are set out in the current regulations, the amount and length that applies to a specific case should be confirmed against the notice given at the roadside or an official Ontario source, rather than relied on from a general article like this one.

Frequently Asked Questions

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