• 0 Posts
  • 74 Comments
Joined 22 days ago
cake
Cake day: August 10th, 2026

help-circle
  • the senate of Canada found that it makes users, ‘MORE cautious’

    Chapter 8 – Driving under the influence of cannabis

    If there is one issue, other than the effects of cannabis use on young people or the effects of substance abuse, that is likely to be of concern to society and governments, then it is certainly the effect of the use of cannabis on the ability to drive a vehicle. We are already familiar with the effects of alcohol on driving and the many accidents involving injuries or deaths to young people. In spite of the decreases in use noted in recent years, one fatal accident caused by the use of a substance is one accident too many.

    Next to alcohol, cannabis is the most widely used psychoactive substance, particularly among young people in the 16-25 age group. Casual use occurs most often in a festive setting, at weekend parties, often accompanied by alcohol. People in this age group are also the most likely to have a car accident and are also susceptible to having an accident while impaired.

    Cannabis affects psychomotor skills for up to five hours after use. The psychoactive effects of cannabis are also dependent on the amount used, the concentration of THC and the morphology, experience and expectations of users. But what are the specific effects of cannabis on the ability to drive motor vehicles? What are the effects of alcohol and cannabis combined? And what tools are available to detect the presence of a concentration of THC that is likely to significantly affect the psychomotor skills involved in vehicle operation?

    This chapter is divided into three sections. The first considers the ways of testing for the presence of cannabinoids in the body. The second analyzes studies on the known prevalence of impaired driving, in both accident and non-accident contexts. The third and last summarizes what is known about the effects of cannabis on driving based on both laboratory and field studies. As in the other chapters, the Committee then draw its own conclusions.

    The Committee feels it is quite likely that cannabis makes users more cautious, partly because they are aware of their deficiencies and compensate by reducing speed and taking fewer risks. However, because what we are dealing with is no longer the consequences on the users themselves, but the possible consequences of their behaviour on others, the Committee feels that it is important to opt for the greatest possible caution with respect to the issue of driving under the influence of cannabis.

    Given what we have seen, we conclude the following:

    Ø Between 5% and 12% of drivers may drive under the influence of cannabis; this percentage increases to over 20% for young men under 25 years of age;

    Ø Cannabis alone, particularly in low doses, has little effect on the skills involved in automobile driving. Cannabis leads to a more cautious style of driving. However it has a negative impact on decision time and trajectory. This in itself does not mean that drivers under the influence of cannabis represent a traffic safety risk;

    Ø A significant percentage of impaired drivers test positive for cannabis and alcohol together. The effects of cannabis when combined with alcohol are more significant than is the case for alcohol alone;

    Ø Despite recent progress, there does not yet exist a reliable and non intrusive rapid roadside testing method;

    Ø Blood remains the best medium for detecting the presence of cannabinoids;

    Ø Urine cannot screen for recent use;

    Ø Saliva is promising, but rapid commercial tests are not yet reliable enough;

    Ø The visual recognition method used by police officers has yielded satisfactory results; and

    Ø It is essential to conduct studies in order to develop a rapid testing tool and learn more about the driving habits of cannabis users.

    https://sencanada.ca/en/content/SEN/Committee/371/ille/rep/summary-e