How does cannabis use affect driving?

Tetrahydrocannabinol (THC), the psychoactive compound in cannabis negatively affects driving and driving-related behaviour. Cannabis impairment (being high) affects driving by slowing reaction time, distorting perceptions of the distance between vehicles, and shortening your attention span. Driving simulator tests show that drivers high on THC are more likely to be at risk of car accidents.

Cannabidiol (CBD) is another compound found in cannabis plants. It’s commonly used as a sleep aid and a supplement to help people relax. CBD usage does not impair driving ability. Driving while consuming CBD is not illegal in Ontario and Canada, nor do roadside tests for cannabis use test for CBD.

When is it safe to drive after consuming cannabis?

There are no hard and fast rules about how long after consuming cannabis you can drive. The effects of cannabis vary based on factors such as how much you consume, how you take it (smoking, eating edibles, taking tablets), the amount of THC you took, and your body’s individual sensitivity to the drug. The general recommendation, however, is to wait at least six hours before driving if you have taken cannabis.

How do police test for cannabis impairment roadside?

There are three ways for a police officer to test for cannabis impairment. The first is the field sobriety test (FST). The FST is a roadside test where the police officer inspects your eyes and asks you to do a number of physical tasks including walking in a straight line, standing and turning, and standing on one leg. If the police have reasonable suspicion that you are under the influence of drugs, they can also demand a roadside sample of your saliva to test later.

The last test is the Drug Recognition Evaluation (DRE). The DRE is a test that is done inside a police station after you have been arrested under suspicion of impaired driving. The DRE is a 12-step process where a trained officer takes a sample of your blood or urine and tests other biomedical markers such as blood pressure, temperature, and eyesight. Since you are detained when the DRE occurs, you are entitled to speak to a lawyer before the test. However, you are not entitled to refuse the DRE.

What is the definition of impaired driving?

You can be convicted of intoxicated driving offences for either:

  1. Being “impaired” while driving, or;
  2. Having more than the specified threshold of a substance in your body while driving.

Section 320.14(1) of the Criminal Code prohibits impaired driving, irrespective of how you became impaired. Impaired driving simply means any driving that is affected by drugs (including prescription drugs) or alcohol to any degree.

The specific thresholds the law allows vary on which substance is identified in your body. For alcohol, this is the “over 80” rule (i.e. you cannot have a blood alcohol concentration of over 80mg/100mg blood while driving) while for cannabis, the measurable threshold is 2ng THC per millilitre of blood.

Since impaired driving and driving while over the prescribed limit are separate offences, it is possible to be charged (and eventually convicted) for impaired driving even if your blood THC levels are less than 2ng/mL in the case that you are sensitive to cannabis. On the other hand, it is not possible to be convicted for both impaired driving and elevated drug levels while driving since both crimes stem from the same offence.

What are the legal consequences of driving while high?

Driving while high is illegal in both Ontario and Canada. In Ontario, the Highway Traffic Act bans impaired driving while at the federal level, driving while high is a crime per section 320.14(1) of the Criminal Code.

In Ontario, the penalties for driving while high are:

  • If you failed the FST:
    • If this is your first offence, 3-day immediate license suspension and a $250 fine.
    • If this is your second offence, a 7-day immediate license suspension, mandatory education and treatment, and a $350 fine.
    • If this is your third offence, a 30-day immediate license suspension, mandatory treatment or education, an ignition interlock (that is, a breathalyzer attached to your ignition) for six months, and a $450 penalty.
  • If you failed a DRE:
    • You will always face an immediate 90-day license suspension, have your vehicle impounded for 7 days, and have to pay a $550 fine.
    • For your second offence, you will have to go to an education or treatment program, and if this is your third offence, you will have to also have an ignition interlock device for six months.

The criminal penalties for driving while high (section 320.14(1) of the Criminal Code) are stated in section 320.19(1). They are:

  • If prosecuted by indictment, both impaired driving and testing for more than 5ng/mL THC (or at least 2.5ng/mL THC in addition to a blood alcohol level of 50mg/100mL blood) within two hours of driving have a minimum penalty of a $1000 fine and a up to ten years imprisonment.
    • For second and third offences, there are mandatory minimum sentences of 30 days and 120 days imprisonment respectively.
  • If the Crown prosecutes summarily, the penalty for testing between 2ng/mL and 5ng/mL THC after two hours of driving is a maximum $1000 fine.

What are the Charter issues with cannabis and driving?

As the police conduct their investigation, they are bound to respect your Charter rights from their first interactions with you, right until your release. If you are arrested and your vehicle is searched, your Charter rights are being interacted with by the police and it may be important to have a lawyer review the interaction to flag violations which may not be apparent to the average person.

Most importantly, if you have been arrested after a roadside sobriety test and taken to the police station, be aware that you have the right to speak to a lawyer (section 10(b) of the Charter) and to remain silent (section 7 of the Charter).

How Can Our Firm Assist You?

If you have been charged with an impaired driving offence, our team is here to help. The lawyers at Lakin Afolabi Law are knowledgeable and experienced in the area of impaired driving and other Criminal Code driving offences. We will review the facts of your case and advance defences that may be available to you, such as:

  • You were not driving the vehicle at the time of the offence
  • The breathalyzer was not functioning correctly
  • Your vehicle was physically incapable of moving
  • Your breath samples were not taken as soon as practicably possible after the offence was committed
  • Your first breath sample was taken later than two hours after the offence
  • You drove because it was necessary to do so.
  • Police did not inform you of your rights or interfered with the implementation of your rights
Lakin Afolabi LPC blog material is screened for authenticity as of the date of posting and accurately reflects the law to the best of our knowledge. Because the nature of the legal landscape is ever-changing we do not guarantee the future accuracy or completeness of this blog material past the date of posting. This material is not a replacement for advice received from our team of legal professionals. Any action you take upon the information on this website is strictly at your own risk.