Cannabis has been legal in Ontario for nearly a decade, and there are laws in place that prohibit driving while impaired by cannabis. There are serious implications for drivers who don't comply with laws related to cannabis use across multiple levels of legislation.

From criminal charges for impairment to strict rules on testing and even on how cannabis is stored in your vehicle, here’s what every driver needs to understand before getting behind the wheel.

Impaired Driving Laws in Ontario

The first piece of relevant legislation is the federal criminal code. Being under the influence of alcohol or recreational drugs, such as cannabis, while in care and control of a vehicle is illegal and can lead to serious consequences, such as criminal conviction, imprisonment and fines. If you are convicted of impaired driving, which includes being in excess of the THC blood limit, additional sanctions under the provincial Highway Traffic Act (HTA) apply. This includes a driver’s licence suspension, completion of an education/treatment program and installation of an ignition interlock device — a breath monitoring unit wired to a vehicle’s ignition.

It's important to note that Ontario also has a zero-tolerance policy for some drivers. Those who hold a graduated licence — a G1 or G2; drivers aged 21 and under; and drivers operating commercial vehicles — are legally prohibited from driving with any amount of cannabis in their system.

Under the HTA, failing or refusing to comply with a drug test or roadside sobriety evaluation will result in an immediate licence suspension. This can also include the requirement to complete an education course, a fine and a seven-day impoundment of your vehicle.

Consequences for Driving Under the Influence

Ontario has continued to strengthen these sanctions over time, with the most recent changes coming into effect in January of 2026. Drivers who have a blood alcohol content (BAC) between 0.05–0.079 or fail a standard field sobriety test, now face an increased immediate licence suspension of seven-days (increased from three), are required to complete an eight-hour education course for their first offence and receive a $250 fine. A second offence comes with a 14-day (increased from seven) licence suspension, a required 16-hour treatment program and a $350 fine.

Consequences in Ontario for a BAC of 0.08 or more, failing or refusing to comply with testing or performing poorly during a drug recognition expert evaluation include: Immediate 90-day licence suspension, seven-day vehicle impoundment, eight-hour education course and a $550 penalty. If convicted, drivers face additional fines, potential jail time, a minimum one-year licence suspension, mandatory education or treatment program and must install and use an ignition interlock device for at least one year. These consequences apply to first-time offenders, with escalating consequences for repeat offenders.

Cannabis Safety Tips

The provincial Cannabis Control Act (CCA) prohibits cannabis inside the vehicle unless it’s unopened in its original packaging, or packaged in a container that is fastened closed, or is otherwise inaccessible to anyone in the vehicle. While not a criminal offence, non-compliant care and control of cannabis inside a vehicle can still result in a fine.

To help you stay compliant and avoid unnecessary fines or complications, here are a few key practices to keep in mind.

1. Keep all cannabis products closed and in the trunk

The goal is to keep cannabis inaccessible. If an occupant can reach into the trunk area, the bag or container of cannabis should have a locking mechanism engaged and be stored in a part of the trunk that can’t be reached. A trunk that is inaccessible to any occupant meets the required standard. By contrast, court decisions have consistently found that a zipped bag or knapsack does not. When in doubt, don’t keep cannabis in the vehicle at all. It doesn’t matter who it belongs to; the driver is still liable under the CCA.

2. Don’t consume before driving

Consuming cannabis before driving can put your blood THC level above legal limits, resulting in a criminal conviction — even if you do not feel like you are impaired. A regular consumer can still have 2 mg of THC in their blood (the summary conviction legal limit) days after consumption. Even small amounts of cannabis can leave you feeling impaired — whether surpassing the legal blood THC limit or not, so it’s important to recognize that you may be intoxicated even with low-dose consumption. When in doubt, either abstain from cannabis use altogether when intending to drive or abstain from driving when consuming cannabis.

3. Don’t consume in the vehicle

Cannabis, especially when smoked or vaped, can leave a strong odour. Police officers can use this (along with other factors such as the presence of drug paraphernalia or crumbs) as reasonable grounds to search a vehicle. Even if it does not result in charges, it can still be distressing and time-consuming.

Understanding how these laws work together is key to staying safe and avoiding serious consequences. While cannabis is legal, driving under its influence — or failing to follow the rules around storage — can carry penalties that are anything but minor.

Taking a cautious approach, from when you consume to how cannabis is stored in your vehicle, can help you stay on the right side of the law and keep the road safer for everyone.

Understanding how these rules apply to you can go a long way in avoiding penalties and making safer choices every time you get behind the wheel. Visit www.caasco.com/cannabis to stay informed about cannabis laws in Ontario and help protect yourself and others on the road.