We all know that in unrelated traffic stops police often claim to smell the odour of marijuana as an excuse to search the vehicle. I have always argued that the odour of burnt cannabis in a car is indicative that there WAS (past tense) weed smoked in the car at some time in the past not that there’s more in the car now. Besides, we also know how the smell of any smoke can linger on a person or in a place for a long time. In Canada, because odour is transient, it blows in the wind and the assertion cannot be tested in court, the odour of cannabis alone is NOT sufficient to establish reasonable grounds to believe cannabis is in the vehicle. More is required to justify a search.