Amusing attempt to decrease speeding in parking lots and driveways. Usually created by mounding asphalt on road surface and allowing to set, then painting a cheery yellow, white or stripes of either color. When driven over at speed, speedbumps provide a short, savage launching pad, resulting in the offending vehicle lunging upward, then downward. Occupants are usually seen bonking their heads on the ceiling of the vehicle as the merciless forces of inertia demand payment. Conversely, when driven over slowly, vehicles are simply jostled slightly, and head bonking rarely occurs.
For a truly vicious effect, speedbumps can be left unpainted, so as to surprise drivers even more.