This paper describes the complete hardware and software design of a new automatic vehicle identification (AVI) system for use on multi-lane roads and where the traffic lane disciplines are not always complied with. The system employs the randomized time division multiplexing (TDM) technique for avoiding collisions of signals transmitted from several vehicles coexisting in a wide angle detection zone of 90°× 83°× 20 m. Experiments carried out in a fully furnished teaching laboratory show an error free detection for the two-way communication between the toll-site AVI equipment and the identification tag at a IMbit/s data rate.