Had a fatal accident happened while the person driving was high? Yes. But if you were actually educated you'd know that there have been multiple studies/tests done. Marijuana has a very small effect on a person's ability to drive, and in almost all cases the person drives slower and more carefully due to the paranoia effect. The same cannot be said for alcohol. That being said, nobody should drive under the influence of anything. (Heavy prescription drugs may be more dangerous than anything).