Perhaps I could explain our process going into this when we were discussing the numbers.
As I said before, we did look at other countries. Predominantly this is about smoking because of how THC gets in so slowly with regard to edibles. What is important is recency of use.
You could take a number like 100 nanograms per millilitre and say that it is very recent use. Basically, the person is smoking and somebody is taking a blood sample at the same time. Toxicologists could get behind that. It would be recent use. But this is not reality for how it looks on the road, so we are trying to incorporate studies that looked at concentrations that could potentially be associated with recent use, as well as incorporating that no back calculation can be done, and that it takes time to get a blood sample.
On that note, with regard to the legislation, a blood sample has to be taken within two hours of the offence or else there is nothing to catch that result afterwards. If a blood sample is taken two and a half hours later, there's nothing in this bill that can happen, because there is no back calculation.
Five was the number that was decided upon because in general the literature pointed towards occasional users, among them five would mean recent administration for smoking. This comes with a caveat that it does not include those chronic users who have residual levels in their bloodstream for extended periods of time. As well, there aren't a lot of studies on the increase of potency that's available now.
That was our idea behind coming up with these numbers. One nanogram meant recent administration, as far as we can say that. I mean, there will always be exceptions to the rule. All those other factors were built in. Two was suggested just because there are people who can certainly be impaired below a concentration such as five, and the THC drops so rapidly that you could be at two even though there was recent administration.