Canadarsquo;sdrug-impaired drivinglaws state that itrsquo;s a criminal offence to have consumed an illegal amount of drugs within 2 hours of driving. When police pull over a driver for a legal stop and have a reasonable suspicion that the person is driving under the influence of marijuana, they can determine whether the driver has consumed pot by testing whether the driverrsquo;s bodily fluids contain THC, the psychoactive ingredient in cannabis. In Canada, you can now legally: TheCannabis Actcame into force on Oct. 17, 2018. This law creates a framework to control the production, distribution, sale and possession of cannabis, and sets possession limits, health and safety standards and marijuana etfs canada criminal penalties for violations.