From Tyler Cowen:
"By its very design, a speed bump is a deliberate obstruction with maximum transparency as such. It is sending a message that the social goals of safety or neighborhood quiet are sufficiently important that it is worth slowing people’s progress when they travel. There are many regulations that try to make our lives safer, but most of them are hidden, with nontransparent costs, such as auto-safety regulations as applied through crash tests. A speed bump, in contrast, can work only if people notice it each time. So to the extent a society accepts speed bumps, it is visibly advertising the notion that limits to fast transportation — a symbol of progress — are acceptable in the name of safety and cozy locality."