[mcv]

Exactly. Ideally, only the street should have real street functionality (houses and shops directly accessible from the street). Maybe the collector too; it's meant to have many streets connecting to it, so access to car parks for shops makes a lot of sense there too. But anything arterial should just be about getting people from one end to the other as smoothly as possible.

There's one more category that's often ignored in this list: the rural road. There, the functions can mix without any problems, but only because of its very low density and low use; very little traffic means you can still cross the road easily, and have time to turn into drive ways and things like that without hindering anyone.