"Moreover, emerging scientific research indicates that cannabis actually has far less impact on the psychomotor skills needed for driving than alcohol does, and is seldom a causal factor in automobile accidents. A pair of international studies released in the spring of 2001 bolsters this argument. "
Ummm...my recollection of this from high school is somewhat different. It would be hard to describe my driving friends as anything less than impaired.
Let me put it to you this way. How many people do you personally know who wrecked while high on pot and only high on pot?
I know of none.