HOW MUCH WEED DO YOU HAVE TO CONSUME TO EXCEED THE LEGAL DRIVING LIMIT? – “There are two prohibited levels for THC, the primary psychoactive component of cannabis: it is a less serious offence to have between 2 nanograms (ng) and 5 ng of THC per ml of blood. It is a more serious offence to have 5 ng of THC or more per ml of blood.” Does that help? Of course not. Nobody knows how much anyone has to consume to exceed these limits. The government just picked a random number and will convict you of “serious criminality” if you exceed it. If you are not a citizen of Canada you will be ordered deported.