A vehicle communication system providing, in one embodiment, wirelessly transmitting and receiving messages regarding the status of parking spaces, such as empty or occupied. Only vehicles belonging to a predetermined set are able to decrypt such messages, in one embodiment. Message formats to comprise a group of parking spaces are described. An embodiment includes a communication mode specific for vehicles in a parking lot. An embodiment includes messages describing the shape and size of vehicle entering or leaving a parking space. Efficient methods of coding vehicle type are described. Methods of improving the operational efficiency of a vehicle communication system, including passive RF reflectors, audio and video messages, safety, courtesy and social messages, and compliance with vehicle restrictions are in some embodiments.