Abstract: A door control system, particularly suited for multiple door rapid transit vehicles wherein car operating parameters including car speed sensing (5), traction propulsion sensing (7), and other indications of internal circuitry establish and continuously test for predetermined conditions under which a power operated door can be opened. A low speed detector (1) incorporates a micro-processor (8) and a no motion relay (3) to evaluate car and circuit operating conditions, providing control of all transit car doors. The micro-processor and associated control equipment also recognize predetermined failure modes. Occurrence of predetermined failure modes results in the overall system (1) reverting to a more conservative state. Coded indication (2) of failure modes is provided for easy indentification and corrective action by train operating crews.