Comment by jfengel

There are people who don't care at all, but most people will drive around the speed that the road encourages. That includes things like how straight the road is, what kinds of interactions, the presence of sidewalks, trees, and many other clues.

Neighborhoods can be designed to send signals about the appropriate speed, without signs or rumble strips or speed bumps. Some people will ignore these, just as they'll ignore signs, but most drivers will do what they expect for that kind of road.