Actually, my original statement had nothing to do with comparing driving safety, and I'm not sure to what you're objecting.   You should re-read it.  People have different tolerances for alcohol, and people have different tolerances for marijuana, and assuming marijuana will not impact your brain and motor skills is unwise and dangerous.  One thing is clear: marijuana advocates are defensive about it. And yes, there are other sites than the one you posted, with other opinions.