Driving after using cannabis doubles your risk of causing an accident. In fact, the most common cannabis related harms are fatal and non-fatal injuries from motor vehicle accidents caused by cannabis impairment. Cannabis use impairs your concentration, alertness, reaction time, and your ability to make quick decisions or handle unexpected events. It can also make it harder to judge distances and time, and affect coordination. There is no standard waiting time to drive after using cannabis. The Canadian Low Risk Cannabis Use Guidelines and the Canadian Public Health Association recommend not driving for at least six (6) hours or longer after consuming cannabis. Cannabis impairment may vary and last longer than six hours depending on a personu2019s tolerance, age, the amount of cannabis consumed, the potency of the cannabis, whether the person has pre-existing health conditions, and whether it has been used in combination with other substances.