Okay, just to put this in context, you're citing the report we wrote, in which we tried our best to flush out all of the issues with respect to cannabis and driving, as well as the other drugs. I will say that cannabis is not a simple drug. There are a variety of considerations with respect to different types of users, different types of use, and effects in the body.
That whole paragraph was about chronic users, so people who routinely administer a cannabis product. Predominately this was about smoking or the inhalation route, because there is obviously another route, which is the edibles, as people do consume it as well, and that comes with a whole different interpretation.
With respect to this, THC, which is the parent ingredient, the primary psychoactive ingredient in cannabis products—and I'll just use the short form, because I'm assuming we're all familiar with the short form—is a lipid-loving drug, which means it goes into fatty tissues. If you are an occasional user, then inhalation will result in a THC concentration rapidly rising and rapidly declining in a blood sample and then it being redistributed to all the fatty tissues, including the brain, and that's where it has its effects.
In a habitual user, so someone who uses on a daily basis or multiple times a day, this THC will then redistribute through the same mechanism. The THC concentration rapidly escalates or rapidly declines in a blood sample and it then goes into the fatty tissues. But in a chronic user, the THC will accumulate in the fatty tissues. In an occasional user, the THC concentration in the blood will decline to an undetectable level, whereas in somebody who repeatedly administers this drug via smoking and then for a period of time, for experimental purposes, stops using the drug, there tends to be residual levels of THC in their bloodstream.