These sleeping policemen actually flatten when the vehicle is traveling the speed limit, but stay upright when someone is speeding. The new design uses a small damper inside to flatten out when a car drives over it at low speed, but higher forces from a faster vehicle keep it upright, causing a nasty jolt. To make them more visible than your typical speed bump, they're outfitted with LEDs all around. The designers say their goal was to encourage drivers to maintain a constant slow speed, reducing the amount of stops and starts made, and thereby the amount of exhaust pollution from the car. The world's first green speed bumps? These are just a concept for now, but hopefully someone will put them into production soon, and bring them to So. Cal.