Guide-by-wire vehicle steering involving (a) preparing a vehicle lane in a roadway with a passive, lane-following, elongate, lateral-triangulation responder, (b) equipping a selected vehicle having signal-controllable steering mechanism with a lateral-triangulation transceiver operatively associated, and interactive, with the responder, and signal-control-linked to the selected vehicle's signal-controllable steering mechanism, (c) with such a vehicle traveling along the roadway, interacting the transceiver and the responder, and (d) by such interacting, applying, as necessary, control signals from the transceiver to the vehicle's signal-controllable steering mechanism, thereby to control vehicle steering so as to assure vehicle following of the prepared vehicle lane. Also disclosed is system structure capable of performing these vehicle-steering steps, and selectively, additionally, communicating non-position roadway information in addition to steering-control information.