The Acute and Residual Effects of Cannabis on Driving and the Risk of Collision for People who Drive after using Alcohol and Drive after using Cannabis

• Main Author: Sayer, Gillian
• Other Authors: Brands, Bruna
• Language: en_ca
• Published: 2014
• Subjects: cannabis; driving; 0419
• Online Access: http://hdl.handle.net/1807/44065

Although the impairing effects produced by alcohol and their direct effect on the driving task have been well defined for decades, similar information on the effects of Δ9-tetrahydrocannabinol (THC) following cannabis use in relation to driving skill is lacking. A combination of experimental and epidemiological studies is presented that examine the effects of THC on driving and collision risk. Preliminary data from a driving simulation study explores how THC impairs driving ability both acutely and residually and consideration is given to the challenges faced when conducting this type of research. Epidemiological data from a population-level survey demonstrate that the self-reported concurrent behaviours of driving under the influence of alcohol (DUIA) and driving under the influence of cannabis (DUIC) impart an increased risk of past-year collision more than 3 times greater than reporting driving after using a single substance, or not driving following substance use.