At present in many urban areas it is necessary to adopt some actions to reduce the pollution in the centre. This aim may be reached either through structural actions or through innovative management strategies, which allows dynamic pollutant level monitoring and control. Such a system based on an Automatic Vehicle Monitoring system (AVM) integrated with the Urban Traffic Control System (UTCS) is presented. This paper describes first the AVM system which has been realised in the city of Trieste in Italy and then the model used to reduce the pollution level on critical links. In particular the new architecture of the system allows to extend the usual objectives of this kind of system. The bus can be viewed as a mobile sensor device, able to collect data on the dynamic behaviour of the environmental conditions. The measures are then related to the position of the vehicle and transmitted to a central site, using the standard features of the AVM system. At the central site level the data are stored and used to adopt suitable control actions, based on a direct link with the Urban Traffic Control System. Two kinds of control actions have been implemented. The first one deals with usual priorization schemes for the buses, the second action is taken in order to reduce the pollution level on critical links in the network by changing the traffic behaviour on the same links. A model, used to perform the last action, is also described. It is mainly based on the concept of filtering the traffic in-flows at some intersections and it allows to modify dynamically the traffic signal plans in order to reduce the traffic flows in the critical points. Finally some results of the implemented techniques are presented and discussed.
Abstract