Idaho, Delaware, Arkansas, Oregon, Washington, Utah, North Dakota, Oklahoma, Colorado, Washington, DC, and Minnesota :)
I don't know what motorists know or don't know, but why would that make a difference?
An Idaho stop has to do with cyclists not having to needlessly wait at stop signs or red lights, so drivers don't really have to think about it, since they likely won't even be at those same intersections where an Idaho Stop is used. It **decriminalizes ** inefficient, dangerous, nonsensical stops for cyclists.