A control system for a plurality of vehicles provides for efficient communication while minimizing necessary bandwidth and communication delays. Periodic reports are received from the vehicles by a controlling authority. All vehicles in motion continually receive a permissive GO signal. When the controlling authority determines a vehicle should be stopped, it immediately addresses a STOP command thereto. The addressed vehicle acknowledges the message. Failure of the controlling authority to receive the acknowledgement results in removal of the permissive GO, stopping all vehicles.