Mr. Speaker, that is an excellent question. It is precisely my concern with roadside testing for marijuana, which we heard all about in Bill C-46. The justice committee heard testimony from expert witnesses who said, as the member said, that the level of THC in the blood being measured with roadside tests had absolutely nothing to do with impairment. The amount of THC goes up in the blood, but it is only when it is out of the blood and in the brain that it actually impairs people. Therefore, these tests have no relation with impairment, and that is a real difficulty.
We have to find a different way for measuring impairment with THC than with alcohol. As he said, with alcohol, it is very different. The amount of alcohol in someone's blood is highly correlated with the amount of impairment, but it does not work that way with marijuana. As I mentioned in my speech, groups will be fighting Bill C-46 in court over just this issue. People will be charged for being impaired when they are not impaired at all.