alcohol would be stupid to drive with but weed is not a good choice either depending on how it affects your cognitive functions
I was a proffessional driver for over 5 years, driving for at least 4-6 hours a day. While I rarely smoked while driving (I thought thats a bit of a bait way to be pulled over) I often had a joint at roadside cafes and ALWAYS before i got onto the road. Naturally after driving as intensively as that, me and all my colleagues were ultra confident drivers, all of us wouldnt hesistate to drive at 90mph all the way so long as it was possible. I found that when high, your reactions were slightly delayed but you compensate by driving slower... your far less confident at your driving ability. After driving high every day over that period, I still have a completely clean license while most of my colleagues have some points at least (its hard to avoid, when theyre so keen to get money out of motorists) and around half of them are disqualified. I have more than put it to the test and I think that most accidents happen due to over confident drivers, the natural anxiety caused by cannabis relieves this problem and I think that a lot of young drivers would be far more responsible if they drove stoned every now and again.