Cannabis, driving and implications for youth / : Conduite après usage de cannabis et les jeunes

However, the evidence indicates that cannabis adversely affects the ability to drive safely and doubles the risk of being involved in a serious traffic crash. [...] The potency of the drug is usually expressed as the percentage of THC per weight of dry cannabis. [...] The majority of THC is excreted in the feces with the remainder being eliminated as metabolites in the urine. [...] THC blood levels depend on the amount ingested, the concentration of THC in the cannabis, the amount of body fat, the extent of experience with cannabis and the manner in which the drug is used. [...] Pattern and manner of use, previous experience and extent of use, concentration of THC, acquired tolerance, sensitivity and differences in the amount of body fat can all influence the effects observed.