Retractable speed bump

摘要

A retractable speed bump mounted in a street, road or roadway for controlling the speed of vehicles, which includes a generally rectangularly-shaped encasement containing upper and lower, relatively movable, wedge-shaped members slidably fitted in the encasement and configured to cooperate by means of friction-reducing means such as ball bearings in adjacent, inclined faces to selectively raise the top of the upper member above street or road level responsive to activation of a hydraulic cylinder attached to the encasement and the lower member.