Again, we can't test for it. The NHTSA says they can't test for it, end of debate. I am not saying they will never in a million years have a way to test for it. I am saying that right now it is not possible. And yes, I am correct in that, and you were wrong when you disagreed.
So this is how you admit you were wrong, lol. Whatever. It doesn't matter, as the point is now made. We can't test for current marijuana impairment. So while some people may think it's a good idea to legalize marijuana and a bad idea to drive after smoking marijuana, you either have to legalize both, make them both illegal, or make people forfeit their driver's license if they indulge in marijuana.
My point was that I don't think driving under the influence is a big enough deal to make it illegal. Mostly because there is no way to test for it, but also because I don't think the average pot smoker adds much of a danger on the roads. Add to that the fact that driving like an idiot or being dangerous on the roads is already illegal.