Written by: Samantha L. Posluns, Associate Lawyer, Falconeri Munro Tucci LLP

The purpose of this series is to shed light on some of the less obvious areas of the law that is being impacted by Canada’s recent legalization of recreational cannabis consumption.

Most Ontario drivers are familiar with the standardized roadside detection methods for alcohol intoxication, however, in the wake of Canada’s Cannabis Act many are unclear as to how drivers will be monitored for cannabis use. This article will summarize some of the recent changes to Canada’s criminal laws, as they relate to driver safety and cannabis detection methods.

The federal Cannabis Act regulates many aspects of cannabis consumption, including possession and lawful places of use. The Act strictly prohibits the consumption of cannabis while operating a motor vehicle. The legal maximum for possession by an individual over the age of 18 is 30 grams of dried cannabis (Note that 1 gram of dried cannabis is equal to 5 grams of fresh cannabis, 15 grams of edible product and 70 grams of liquid product.). The penalties for possession over this limit include a fine of up to $5,000.00 or imprisonment for a term of up to 5 years (depending on how the offense is prosecuted under the Criminal Code). Recreational cannabis consumers must be aware that even if a roadside search does not result in a charge for intoxication, possession over the prescribed limit has serious consequences.


The federal government has also enacted the Impaired Driving Act which amends Canada’s Criminal Code. The legislative intent behind these amendments was to facilitate a more robust drug-impaired driving regime, including the creation of new types of criminal offences and authorizing the use of roadside screening devices able to detect cannabis intoxication.

While pre-amendment provisions of the Criminal Code defined the operation of a motor vehicle while impaired as a criminal offence, they were vague as to what constituted impairment, particularly with regard to drug intoxication. The Impaired Driving Act has amended the Code to define three cannabis-related offences and specifies the detectable level THC or THC/alcohol combination levels required for a finding of impairment. The penalties upon conviction of these offences range by degree of seriousness.

  • A finding of between 2 and 5 nanograms of THC per millilitre of blood within two hours of driving is considered a summary conviction criminal offence.
  • A finding of 5 nanograms of THC per millilitre of blood within two hours of driving is considered a hybrid offence, which may be prosecuted either by summary conviction or by indictment.
  • A finding of a blood alcohol level of 50 milligrams per 100 millilitres of blood combined with a THC level greater than 2.5 nanograms per millilitre of blood within two hours of driving is also considered a hybrid offence.

The summary conviction offence is punishable by a strict fine of $1,000.00. Both hybrid offences are punishable by mandatory penalties of $1,000.00 for a first offence and escalating penalties of imprisonment for repeat offenders. The more serious the circumstances surrounding a hybrid offence are, the more likely that it will be prosecuted by indictment. If prosecuted as a summary conviction, the maximum penalty is up to 18 months imprisonment. If prosecuted as an indictable offence, the maximum penalty is up to 10 years imprisonment. In cases where the impaired driving results in bodily harm, the maximum imprisonment period is 14 years and where it results in death, a life sentence may be imposed.

Prior to the Impaired Driving Act, breathalysers were the only screening devices that police were authorized to use. This limited roadside testing to the detection of alcohol. Drug intoxication could only be identified through blood sample testing, which required police to first obtain a warrant. Under the new amendments, police are authorized to use saliva testing devices, which, unlike breathalysers, test for THC intoxication. While the results of these tests may not directly lead to a charge, they can be used by police to warrant further investigation, such as a blood testing.

Although legalization has been perceived as a victory for recreational and medical cannabis consumers alike, it has also spawned the enactment of highly specific legislation that seeks to regulate all aspect of consumption. This, in turn, has resulted in the use of advanced detection technologies and harsher criminal penalties. While the constitutionality of these developments remains to be seen, it is clear that authorities have adopted a low-tolerance policy when it comes to cannabis use and driving.