Ethanol is a poison, what, outside of prejudice, would make you find it more likely it's simply a lack of studies? Maybe it simply hasn't reached me, but I never even heard about cannabis being chiefly blamed on a car accident, mind you, people can drive recklessly sober, but, again, if anything cannabis is going to make them be more cautious. For one, surely you have heard of the "paranoia" that cannabis users often get at higher doses, where they feel distant objects are closer than they really are.