Because impaired driving is the leading criminal cause of death and injury in Canada, new drinking and driving laws for 2019 are harsher than ever before. Policy changes in 2016 added drug-impaired driving to drunk driving laws, enhancing the penalty for driving under the influence of drugs.

In 2017, there were over 69,000 impaired driving incidents in Canada—plus nearly 3,500 drug-impaired accidents. Now, the percentage of Canadian drivers who die due to drugs is higher than the rate of alcohol-related driver deaths.

Today, the Criminal Code prohibits operating a vehicle while impaired by a drug, alcohol, or a combination of the two. Penalties range from fines to life imprisonment, but many factors influence the judge’s sentencing decision. 

Prohibited Levels

Blood tests can detect levels of THC—the psychoactive component in cannabis—down to two nanograms.

  • Less severe offences measure between two and five nanograms per millilitre of blood.
  • More severe offences measure five nanograms or more per millilitre of blood.

In short, if you have more than five nanograms of THC in your blood, you will need a good DUI lawyer.

Also, detectable amounts of drugs such as LSD, psilocybin, psilocin (“magic mushrooms”), ketamine, PCP, cocaine, methamphetamine, or 6-mam (a metabolite of heroin) violate drug-impaired driving laws, too. 

How Drugs Affect Your Ability to Drive

Drugs affect your ability to drive by altering your motor skills, slowing reaction time, and causing you to “wander” across the road. Drug usage also interrupts your short-term memory and concentration functions, reducing your ability to respond to problems or handle unexpected obstacles in the street.

In short, using marijuana and driving is not advisable because of how it impacts your ability to drive competently. Many of the effects of marijuana usage mimic the symptoms of driving drunk. Neither is safe or optimal for operating a motor vehicle on Canadian roads. 

Penalties for Driving Under the Influence of Drugs

Both federal and provincial areas mandate a minimum sentence for driving under the influence of drugs. You may be subject to both national and provincial penalties, depending on the ng per mL concentration of drugs in your blood.

Your prior convictions for similar offences also influence the penalties a judge may hand down. In some scenarios, the minimum sentence depends solely on your history of driving under the influence of drugs or alcohol. 

Federal Penalties

The federal penalty for driving under the influence of drugs ranges from a $1,000 fine to up to a lifetime in prison. See the below table for details on the minimum and maximum penalties based on the THC range and accident result.

Provincial Penalties

The provincial penalty for driving under the influence of drugs ranges from a $250 fine and license suspension for the first offence to mandatory treatment programs and vehicle impoundment by the third offence. Drug-impaired driving Ontario can also result in a six-month ignition interlock plus a compulsory medical exam.

Plus, Ontario penalties apply even if your blood levels are less than the limit of five nanograms per millilitre. See the below table for specifics on the minimum and maximum penalties depending on THC concentration and offence number.

Two to five nanograms of THC per millilitre:

Five or more nanograms per millilitre:

Post-conviction of five or more nanograms per millilitre of THC, in addition to federal penalties.

How Much Can I Smoke?

Not much conclusive evidence exists in favour of using marijuana and driving safely afterward. Experts have suggested that even a single puff on a joint can cause TCH readings of over two nanograms.

Plus, THC is fat-soluble, meaning it can stay in your body for extended periods. A blood test weeks later may still show trace amounts of THC in your system. However, saliva tests won’t detect cannabis use after about six to eight hours. 

Medical Cannabis Users

For many drivers, the question is, can you drive high with a medical card in Canada? Cannabis users who possess a valid prescription do not have the same blood and saliva testing restrictions as the general population.

However, people with medical cannabis prescriptions can still receive impaired driving charges if there is proof that they drove impaired. For example, erratic driving, slurred speech, and other symptoms of impairment in a roadside sobriety test can be enough to land you in court. 


Lawmakers have cracked down on drug-impaired driving in Canada, and for good reason. Driving with drugs or alcohol in your system poses a risk to you, your loved ones, and people on public roads.

Plus, navigating drug-impaired cases can be emotional and stressful. If you are involved in a drug-impaired driving case in Canada, contact a knowledgeable lawyer for help today.

By Published On: August 16, 2023Last Updated: August 16, 2023Categories: Impaired Driving/DUI

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