In my country, high traffic moderate speed (90km/h - 56 mph) sometimes go across rural villages where the speed limit is usually half that. Furthermore, drivers

In my country, high traffic moderate speed (90km/h - 56 mph) sometimes go across rural villages where the speed limit is usually half that. Furthermore, drivers here are notorious for not giving a frack about speed limits. So some of those villages have experienced with various ways to narrow the road. Sometimes it plays only with perception, by adding for instance small plastic poles to separate the lanes. Sometimes it's chicanes or bumps. I can't give figures on the effectiveness of this, but as a driver you instinctively slow down when the road appears narrower. It seems to me more effective than a sign on the side of the road.