Some Issues concerning the Use of Simulation in Advanced Traffic Management Systems

Advanced Traffic Management Systems constitute one of the major envisaged applications of Intelligent Transport Systems. Various architectures and approaches have been proposed and tested in projects of R&D programmes of the European Commission in recent years, as for example ARTIS, KITS and ENTERPRICE, just to mention a few. An approach shared by all of them has been the conception of the system as an intelligent decision support system able of identifying the actual traffic conditions on the network from real time traffic measurements, make a diagnosis of the network state, identify potential or actual conflicts and propose strategies to prevent or alleviate the conflicts. In some cases the decision support functions have been based on evaluating by simulation the scenarios for the proposed management strategies. The simulation provides the human operator with a quantitative basis for the decision making process. A key question on using simulation in this context deals with the model building process in the changing conditions of the real-time decision making framework. This paper discusses some traffic management architectures that use the microscopic simulator AIMSUN2 for these purposes, and describes the structure of a translator that automatically builds the AIMSUN2 simulation model of the selected scenario from GEODYN, an ad hoc Geographic Information System purposely designed for these traffic management applications. Examples from ENTERPRICE project are presented and the quality of the results is discussed.