Cannabis impairment

On this page

Impaired driving

Drug-impaired driving has been a criminal offence since 1925.

Impaired driving is the leading cause of criminal death and injury in Canada.

Cannabis-impaired driving can result in injury or death for you, your passengers and others. Cannabis:

  • impairs your judgment
  • impairs your ability to react
  • increases your chances of being in a crash

Never get into a car with an impaired driver. It is not worth the risk.

Mixing cannabis with alcohol increases your level of impairment and leads to an even greater risk of an accident. Footnote 1

How long cannabis effects last

Some effects of cannabis use, for example drowsiness, can last up to 24 hours, well after other effects may have faded.

The time it takes for the effects of cannabis to wear off depends on:

  • how much and how often you have consumed it
  • whether it was smoked or ingested

There is no standard waiting time to drive after using cannabis. If you are using cannabis, do not drive. Find an alternative:

  • stay over
  • call a taxi
  • share a ride
  • use public transit
  • have a designated driver


Law enforcement officers are trained to detect drug-impaired driving. They enforce drug-impaired driving laws using:

  • Standard Field Sobriety Testing (SFST)
    • typically administered at the roadside
  • Drug Recognition Expert (DRE) evaluation
    • includes a series of tests and a toxicological sample (urine or blood)
  • Oral fluid drug screening equipment
    • Law enforcement can require a driver provide an oral fluid sample on approved oral fluid drug screening equipment
  • Blood samples
    • Law enforcement can demand a blood sample from a driver if they believe the driver has committed an offence

Law enforcement across Canada have SFST and DRE trained officers and the number of officers being trained is increasing. They also have training and access to approved oral fluid drug screening equipment.

Working together against impaired driving

We are working with provincial and territorial partners, as well as other groups such as:


You could face consequences like a fine, criminal charges or even jail time if you drive impaired by cannabis or other drugs. Learn more about how impaired driving laws are enforced in Canada.

Check out the Don't Drive High website on the dangers of drug-impaired driving. The site has a number of videos about the impacts of cannabis impairment.

Workplace impairment

Everyone has a role to play in workplace health and safety. Both employees and employers have a responsibility to address impairment in the workplace, whether it is caused by the use of cannabis or anything else.

The Labour Program, through Employment and Social Development Canada, oversees occupational health and safety for federally-regulated workplaces in Canada. Read about impairment and cannabis in the workplace to find out about your responsibilities as an employer and employee.

You will also find links to tools and resources for employers and employees at the same site.

Footnote 1

Fischer B, Russell C, Sabioni P, van den Brink W, Le Foll B, Hall W, Rehm J, Room R. Lower-risk cannabis use guidelines: A comprehensive update of evidence and recommendations. Am J Public Health 2017 Aug;107(8):1277

Return to footnote 1 referrer

Report a problem or mistake on this page
Please select all that apply:

Thank you for your help!

You will not receive a reply. For enquiries, contact us.

Date modified: