That link that Crackhead posted was interesting. I know a lot of people that are habitual weed smokers, and have never had a crash. I am open to the idea that weed may make some long-term, non-stressed, users a bit better at driving. I'm a bit ashamed to say I've driven on loads of drugs, and I don't even have a license (failed my test, but can drive). The worst was driving pissed, on the motorway, but I was a kid. I used to have a scooter, and regularly rode that, whilst drunk, or on GBL. Very stupid, but at least I'd be the only likely death, in that scenario. The best was after some MDMA and speed. My driving felt perfectly fluid, and I was very gentle with the acceleration. Low doses of each were used. This was about 5AM, on a weekend, so I wasn't exactly a threat to anyone. I'm not proud of any of this, and I'd never repeat it.
I've owned up to my wrong-doings, so you do the same, and let us know if you think weed isn't an issue. I believe it could be for some, but this test is totally flawed, because every fucker is different.