You weren't motivated to even fully read your government source?
So you're making another fallacious argument. Earlier you used a Red Herring, and now you're resorting to the Appeal to Authority. Evidence and reason precede authority, not vice versa.
Moreover, you're treading on a third fallacy of a Straw Man - arguing cannabis shouldn't be consumed while driving - when I haven't argued that it should. My defense of McClain doesn't require my defense of consuming while driving. I don't defend texting while driving either. I don't defend getting enraptured by an emotionally moving song while driving either. BUT THAT DOESN'T JUSTIFY ITS CRIMINALIZATION, especially for merely possession as the article claims. (Oddly enough, it says the officer smelled it, but McClain was only charged with possession.) I defended McClain, for starters, because he didn't injure or threaten anyone. Secondly, as your first source confirms, THERE ISN'T ANY PROOF of it causing auto accidents. Conceivably, yes, if someone was really, really high and tried to drive on a busy highway, but it just doesn't happen. It's not a public threat to the level requiring criminalization, and to my knowledge, there has been no death directly caused by pot. Plus, with the rising advocacy among NFL players to allow cannabis, something that is already widely used within the NFL and in the general public at large, it makes McClain's situation that much more absurd.
And another thing: no advocacy group like NORML is in the business of making frivolous claims (a) without concrete proof and (b) that go beyond their immediate goals. There is no benefit to them or any other anti-Drug War organization to argue secondary or tertiary points which can only be used against them in the court of public opinion. If anything, it pays to stay as close to conventional opinion as possible while deviating only when essential.
So, I'll give you another chance to answer my question: "Do you have any data on traffic accidents caused by marijuana?"