I would use a RFID to construct a car guiding system. I'll put RFID tabs to crossroads so that cars can know where they are and drive themselves automatically. We no longer needs human drivers but "smart cars". We tell the cars the destination and they search for the corresponding RFID tab and calculate the route. When they reach cross road, they find out which crossroad they are at using RFID identifier and decide whether to turn right or turn left. These cars can be especially useful to replace current taxis.