Abstract: Driverless vehicles move in one direction along a path divided into blocks. Movement command signals are radiated from plural elongated radiators per block, arranged end-to-end, the last in each block a departure radiator wholly within the block. A receiver in each vehicle comprises a memory element established in active condition by a momentary "clear" signal and maintained in active condition by a continuous succession of movement command signals. A departure radiator emits no movement command signals while the block directly ahead of it is occupied, but it emits a "clear" signal and continuous movement command signals when that block is safe for entry. Only departure radiators emit "clear" signals; hence, a vehicle which slides into an occupied block cannot continue moving in that block.

Abstract: Driverless vehicles, confined to motion in one direction along a defined path divided into blocks, receive commands from a central unit in the form of encoded command signals radiated from an elongated radiator. Each vehicle progresses only while receiving signals regularly. The radiator comprises two parallel stretches, each extending all along the path but divided into sections, each section being as long as a block but extending across a block boundary, with a section of each stretch paired with a laterally adjacent section of the other stretch. In each section pair, the segment of one section that lies in one block is shielded, the remainder unshielded; the other section of the pair has opposite shielded and unshielded segments.