TWO-WAY COMMUNICATION SYSTEM FOR TRACKING LOCATIONS AND STATUSES OF WHEELED VEHICLES

A system for retrieving shopping carts, the system comprising: a plurality of shopping carts, each of which includes RF communication circuitry coupled to a braking mechanism, said RF communication circuitry being capable of receiving RF transmissions of commands; and a mechanized cart retrieval unit that pushes or pulls a group of nested carts to facilitate retrieval, the mechanized cart retrieval unit configured to communicate with the RF communication circuitry of the nested carts to cause the braking mechanisms of the nested carts to remain unlocked during mechanized cart retrieval.