Own your ow legal marijuana business
Your guide to making money in the multi-billion dollar marijuana industry
Major Studies of Drugs and Drug Policy
Canadian Senate Special Committee on Illegal Drugs
Volume I - General Orientation

Chapter 8 - Driving Under the Influence of Cannabis



The Committee feels it is likely that cannabis makes users more cautious, partly because they are aware of their deficiencies and they 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 in this chapter, we conclude the following.



Conclusions of Chapter 8

Epidemiological data








Data on effects on driving














Further studies



            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.

      This in itself does not mean that drivers under the influence of cannabis represent a traffic safety risk.

      A not insignificant percentage of drivers test positive for cannabis and alcohol together.


            Cannabis alone, particularly in low doses, has little effect on the skills involved in automobile driving.

            Cannabis, particularly in the doses that match typical doses for regular users, has a negative impact on decision time and trajectory.

            Cannabis leads to a more cautious style of driving.

            The effects of cannabis when combined with alcohol are more significant than for alcohol alone.


            Blood remains the best medium for detecting the presence of cannabinoids.

            Urine cannot screen for recent use.

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

            The visual recognition method used by police officers has yielded satisfactory results.


It is essential to conduct studies in order to:

            Develop a rapid testing tool.

            Learn more about the driving habits of cannabis users.


Library Highlights

Drug Information Articles

Drug Rehab