This is particularly visible in Europe, where magnificent centuries-old buildings are constantly scarred by road and parking signs (as well as advertising billboards).
Indeed, every time I visit "old" Europe I notice how street signs tend to be (a) small, and (b) attached to buildings; but it never occurred to me until reading this article that this could be largely explained by the fact that they didn't need street signs until recently.
I can't say I remember a building in Western Europe where traffic signs were mounted on buildings. In cities it's either on or at the edge of sidewalks.
I'm talking about names of streets, not traffic signs.
In any Italian city, "no parking" signs are absolutely everywhere on buildings. If the road is tight enough (which means medieval streets, usually), road signs will also be on buildings, because there is no space for alternatives.