Area of Law: Cannabis Law
Answer # 2554
How soon after using cannabis is it legal to operate a motor vehicle?Region: Ontario Answer # 2554
There is no law about how long after smoking or ingesting cannabis someone has to wait to operate a motor vehicle. Using cannabis does not legally prohibit a person from operating a motor vehicle unless the driver is:
- impaired, and/or
- subject to the Zero Tolerance Rule
However, the Government of Canada has stated,
“Unlike alcohol, the existing scientific evidence does not provide general guidance to drivers about how much cannabis can be consumed before it is unsafe to drive or how long a driver should wait to drive after consuming cannabis. Mixing driving with cannabis, or any other impairing drug, is not safe and poses a danger to our streets and highways.”
How long does cannabis remain in someone’s system?
There are no general guidelines as to how soon after using cannabis someone ceases to be affected by it.
There are a number of factors that can determine both how long cannabis stays in your system and how it will affect you. These include:
- how the cannabis was consumed, e.g. smoked, inhaled, ingested;
- the quantity of cannabis consumed;
- the type of cannabis used, and the potency of the THC (concentration), including cannabis prescribed for medical use;
- if the cannabis was consumed with other drugs (prescription or recreational, and/or with alcohol); and
- how frequently the individual uses cannabis.
An individual’s medical history, as well as age, gender and biology, such as their body mass index (BMI) can also affect how their body processes and metabolizes cannabis when it is consumed.
All of these factors make every individual’s experience different, thus making it difficult to create laws specifying how long a person should wait before driving.
There are, however, general guidelines on how long cannabis remains in a person’s system. According to the Canadian Public Health Association (CPHA):
- Cannabis-infused edibles can take longer to peak (up-to four hours) and
last for a longer duration of time (up-to 10 hours).
- The effects of dabbing, or consuming hash oil, can be felt more quickly because they contain much higher levels of THC (up-to 60-80%).
- The effects of THC can wear off over 2-4 hours when it is smoked, or longer when it is ingested.
How long should a person wait before driving?
Based on their findings, the CPHA recommends waiting at least six hours after smoking cannabis, and at least eight hours after ingesting it before driving.
However, other organizations have different timelines. According to MADD Canada (Mothers Against Drunk Driving), they recommend waiting at least four to six hours after consuming cannabis before operating a motor vehicle.
While these numbers differ, there are definitely circumstances under which you should wait longer, including if:
- you are a new user, or you don’t consume cannabis very frequently;
- you have consumed a large amount of cannabis; and if,
- you have combined cannabis with other drugs and/or alcohol.
Not only is impairment a serious issue because it can affect the safety of both the individual driving as well as everyone around them.
Signs of impairment
Both the Ontario Highway Traffic Act and the Federal Criminal Code legislate the varying prohibited amounts of THC per ml blood. THC is the chemical component in cannabis that causes the mind-altering effects and can impair the users motor or mental functions.
Consuming cannabis that contains THC can impair your behaviour and ability to drive in many ways. For example, it can:
- affect motor skills and coordination
- delay reaction time
- impair both short term memory and concentration
- cause drivers to vary speed and drive erratically
- reduce a driver’s ability to make decisions quickly or handle unexpected events, such as a pedestrian running in front of them
For legal advice and assistance with a cannabis related matter, contact our preferred cannabis law expert, Harrison Jordan Law .
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