On a perhaps related note, a road I used to drive regularly had many curves and signs warning you to slow down at each one. Only one of the curves actually requ

On a perhaps related note, a road I used to drive regularly had many curves and signs warning you to slow down at each one. Only one of the curves actually required you to slow down to navigate it safely. Guess which corner was where all of the accidents happened? If you "cry wolf" too often, people will ignore the speed limit (or caution signs or whatever). If, however, the speed limit is usually appropriate, people will take note when it changes, and drive appropriately.