I'd like to build on what Mr. McKinnon was asking both witnesses, and invite comments from both.
The first point is the per se limits. Both of you support and believe in per se limits. However, the November 2016 report of the task force on cannabis legalization and regulation said the following:
...investment in research to link THC levels to impairment and crash risk is required to support the establishment of a scientifically supported per se limit. In addition, investments to support the development of accurate and reliable roadside testing tools are required.
I think the legislation is wise to not set in the law itself the standard as we do for alcohol, but rather to leave it to regulation, as we will understand over time, whether two nanograms or five or three or whatever is the right number. Are you satisfied that the per se limits will really tell us reliably whether a person's ability to drive is impaired?
I'd invite both of you to comment on that. They're both arbitrary numbers.
You pointed out, Dr. Brubacher, that in fact Norway uses a very different number. How can we be sure that we're getting this right?
Perhaps I could invite you, Dr. Brubacher, to start.