Cannabis can affect a person’s ability to drive safely. Government of Canada guidance identifies effects on motor skills, reaction time, short-term memory, concentration and decision-making. Impairment can vary with the method and amount used, how recently and frequently it was used, and product characteristics.
There is no reliable waiting-time shortcut
The federal guidance does not provide an amount of cannabis or a waiting time after use that establishes when it is safe to drive. Feeling less affected is not a reliable test of driving ability. If there is any possibility of impairment, do not drive; arrange another way to travel.
Legal and safety information
Driving while impaired is dangerous and against the law. The Government of Canada’s impaired-driving information explains the risks and consequences. Health Canada’s cannabis risk guidance provides related health context. This page is general information, not individualized legal or medical advice.
Plan before travelling
Make a safe transportation plan before using any impairing substance. Do not rely on a distance-to-destination, elapsed time or personal confidence as proof that it is safe or legal to drive.
Primary references
Government of Canada: Drug-impaired driving Health Canada: Understanding cannabis risks and reducing harmFor how we use sources and handle updates, see editorial standards. To flag an issue, report a correction.