Cannabis-Impaired Driving and Insurance Implications

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Article Contents
By Aren Mirzaian
Published on May 24, 2020

2 minute read

MyChoice follows a strict content review process designed to ensure reliable and unbiased information.

Article Contents

Cannabis-Impaired Driving & Insurance Implications at a Glance

  • Driving after using cannabis is against the law.
  • Since 2018, fewer people have reported driving after using cannabis, but the drop has slowed, and there was a slight rise in 2024.
  • Even one charge for driving under the influence of cannabis can mean losing your licence, having your insurance cancelled, needing high-risk coverage, and paying higher premiums for years.
  • To be safe, avoid driving on the same day you use cannabis.
  • Police look for impairment using sobriety tests, saliva tests, and checks by trained officers.
  • Having a prescription for medical cannabis does not protect you from being charged with impaired driving.

Is Cannabis Use Behind the Wheel on the Rise in Canada Since Legalization?

When cannabis became legal in 2018, the number of Canadians who admitted to driving after using it dropped from 27% to 18%. This was a good sign, but after reaching a low in 2023, the rate increased slightly in 2024.

Why Cannabis-Impaired Driving Is a Big Insurance Problem

Insurance companies treat impaired driving as one of the most serious violations.

A cannabis-related impaired driving charge can lead to:

  • Immediate licence suspension (often 90 days or more)
  • Criminal record implications
  • Policy cancellation or non-renewal
  • Placement in high-risk driver category
  • Premium increases that last years

Just one impaired driving conviction can make your insurance costs double or even triple.

How Long After Using Cannabis Is It Safe to Drive?

There isn’t a specific amount of time after using cannabis that is always safe for driving.

THC affects everyone differently, depending on how often you use it, how you take it, your tolerance, and your metabolism. People who use cannabis regularly are more likely to misjudge how impaired they are.

For legal and insurance reasons, the safest rule is simple:

Do not drive on the same day you use cannabis.

If you wait until the next day to drive, you lower your risk of being impaired, getting roadside penalties, or having insurance problems.

How Police Check for Cannabis-Impaired Drivers

Enforcing cannabis-impaired driving laws is difficult, and this is where drivers face the most risk.

Standardized Field Sobriety Testing (SFST)

Police may give physical and mental tests at the roadside, done by trained officers. These tests rely on the officer’s judgment and check coordination, attention, and reaction.

Police can also use saliva tests at the roadside to check for recent cannabis use, usually within the last 6 to 8 hours. These tests only show if THC is present, not if someone is actually impaired, so their results are often challenged.

Drug Recognition Experts (DRE)

In more serious cases, a trained officer may assess a driver to see if they are impaired.

Researchers are working on breath tests for cannabis, but there isn’t a widely accepted version yet, like there is for alcohol.

Cannabis & Driving - How Police Check for Impairment

Medical Cannabis and Driving: What Changes?

Even if you use cannabis for medical reasons, it’s still illegal to drive while impaired. Having medical authorization does not protect you from impaired driving charges or roadside suspensions.

In the end, the officer decides if you are fit to drive. If there’s any doubt, you’re taking a risk.

If you need medical cannabis, plan your transportation ahead of time and avoid driving after you use it.

Key Advice from MyChoice

  • A medical prescription for cannabis does not protect you. If an officer thinks you are impaired, the insurance and legal consequences are the same.
  • A single impaired driving charge can affect you for years. Your premiums may double or more, and many regular insurers might refuse to cover you.
  • Plan your transportation ahead of time. If you expect to use cannabis, plan not to drive.
  • Protect your insurance record as much as possible. Not driving while impaired is one of the best ways to keep your premiums low over time.
By Aren Mirzaian

With over a decade in Canada’s insurance sector, Aren is a leading voice in the industry, providing thought leadership on auto insurance, underwriting innovation, and how technology is reshaping insurance.

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