I'm not making this up. And I'm not alone in this (I'll ask a passenger if they too can smell it and they'll often say they can).

I might have a more sensitive nose than most.

Regular pot smokers absolutely stink.

As to your comment about shit, agreed I likely couldn't smell it from a car distance with windows up. Which tells you how much stronger pot smell actually is since I actually can smell that.

Nah, I can confirm I've smelled heavy pot smokers through my car. Happens at least once a week.

I think it's specifically blunt smokers, but I have no data to support that.

I feel like these people can't tell the difference between driving past a skunk and cannabis

I often drive by a home, in a state with legal weed, and I can smell the stench from the road ... every single time too, and no, they aren't smoking outside at all times of day. I'm not anti weed, and I wouldn't complain about someone smoking on their own privacy, or even when alone/not around others, but you can indeed smell it from afar. And if you smoke, you know.