Generally in a Route Guidance system there are some vehicles which have devices on board for helping users in choosing the best path in the road network. Users have to communicate their position (even with an automatic location system) and the desired destination of their trip, then the system provides the path, before the departure or during the trip. The system is defined static if suggestions are based on average historical information. Instead, in a Dynamic Route Guidance (DRG) system the recommended paths are defined on the basis of actual or predicted traffic conditions and the recommendations can be frequently updated. Simple strategies in the selection of information, which suggest individual shortest paths, could generate adverse impact on traffic flows. In fact, to avoid concentration phenomena it is necessary to take into account the global effect of information on the network. The purpose of this paper is to evaluate the capability of a new strategy to reach the user equilibrium conditions in the network, also under big network disturbances (e.g. unpredictable increase of travel demand). For this purpose a traffic micro-simulator has been used in a part of the urban network of Turin. Besides, the global effect on the network has been estimated in order to verify the consequences of DRG systems on the level of service in the network. Finally, the advantages for DRG users are calculated in order to understand whether there could be or not a spontaneous development of the system, given the possible benefits that users could obtain by using the terminal.
Abstract