Alpine towns in Europe have long ago solved this problem. Those roads have a 90kph speed limit that abruptly changes to 50kph or less for a few hundred meters t

Alpine towns in Europe have long ago solved this problem. Those roads have a 90kph speed limit that abruptly changes to 50kph or less for a few hundred meters through a town, then goes back to 90kph. As you can imagine, people speed. A lot. So towns started adding a gratuitous sharp turn at the entrance into town. You fly in doing 90kph, slow down for the turn, and are greeted by a 50kph speed limit. You won't speed back up because why would you. Portuguese rural towns, I've seen, have a similarly brilliant solution – a stoplight outside town. If you approach at speeds above the speed limit, the red light comes on. Forcing you to keep stopping outside very tiny little town. You quickly learn it's faster to just go the speed limit. Another good solution I've seen from little alleys in San Francisco. The speed limit is whatever, but you really shouldn't drive more than 10mph there. Such nice straight road though ... so they stopped being straight. The 1 lane of driving and 1 lane of parking switch sides every quarter block. Forcing you to slow down.