Dunno about that. In my exp, you can get pretty adept at driving when high but that doesn't mean you aren't distracted or have the same concentration and quick wittedness you'd have when sober. Sometimes it's that little edge that keeps you out of an accident. That said, driving dead tired is probably worse than driving high. Driving drunk is worst of all. That's the farthest extreme of the 'stupid' scale.
man this bullshit is about fucking dumb. the only guys who complain about pot smoke is these supposed 'Hardcore' bros who are SO FUCKING intense. i would also like to point out that most are prolly joyless party pissers.