I don't believe you.
Pot heads do not run off the road. They drive 10 miles an hour in the right lane, IF they drive at all.
I know CEO's who do pot. I know cops who do pot, and lawyers, and doctors.
Pot is a lot safer than alcohol. Potheads do not start fights in a rage (like drunks). Potheads do not cause traffic accidents. Potheads do not beat their wives in a (drunken) rage.
They are guilty of massive cheato ingestion, though.
I saw, with my own eyes, dozens of people use drugs of various kinds recreationally on a pretty regular basis for a number of years while in college. None ended up in rehab or dead, all seemed to realize that eventually the fun would end and real life would take precedence. Of course, these were mostly good students, with plans for the future.
I would never say that drugs are harmless, and that no one messes up their life with drugs being the primary instrument. But it seems to me that people drive off the road and ruin their careers/family life with a variety of tools. From my experience, it's the judgment, maturity and character of the individual in question that determines the outcome.
And while I believe, philosophically, that drugs should be legalized, I'm not exactly losing any sleep because they aren't