have a look at this propaganda psa:
http://www.youtube.com/watch?v=JA1CahooPzYlisten to the end"in a roadside study, 1 in 3 drivers reckless drivers who were tested for drugs tested positive for marijuana..."
sounds pretty scary untill you realize that what it
really means is 66% of the reckless drivers tested were
not smoking pot. it doesn't say what their bac was, but chances are, if they were tested for substance abuse at the scene of an incident, the were high on
something.
from those numbers, pot is actually more benign than other substances.
not that i condone driving while under the influence of anything. but as indicated by the recent gallup poll showing 46% of america wants to decriminalize marijuana, it would certainly seem that the vast majority of people realize it's pretty harmless