“I know that one would be a good limit for myself to have before getting in a car and driving. This is essentially a legal shortcut that allows police to lay an impaired driving charge based on a driver’s blood THC level, without having to further prove impairment. The same is simply not true of saliva testing and blood THC levels, and this is where things get tricky. The new per se limits on THC would allow police to immediately lay charges based on the blood test results. But toxicologists point out that blood THC levels do not necessarily mean impairment.

Source: National Post March 28, 2018 15:56 UTC