Short Excerpt from Civilized Life article… “A recent report from the Canadian Centre on Substance Use and Addiction and the European Monitoring Centre for Drugs and Drug Addiction found that all three forms of these tests (saliva, blood and urine) are all unreliable ways to determine if a driver is impaired after using marijuana.So basically, Canada has rules against drugged driving, but no way to actually tell if a driver is actually impaired. ” To read full article click here