In Urban Traffic Control and Management Systems, two basic informations are playing a fundamental role: the Origin Destination (OD) Flows and the Paths of vehicles. This information cannot be computed directly but only be estimated by suitable models and related algorithms. This estimation, usually performed off-line in traffic planning operation, has been now transferred in the more severe environment of the on-line application. Adding to the OD information the knowledge of the different paths chosen by each user for their journey between any nodes of the road network, allows to optimise traffic light signals plans, to provide pre-trip as well as on-trip rerouting information, and to ameliorate the data for off-line traffic and transport planning. The so called Traffic Supervisor System is an on-line system which collects and integrates the traffic, transport and environment information, estimates the state of the actual traffic and pollution, forecasts the status in the following periods and defines a common strategy for all the connected sub systems. These estimations are provided through the use of mathematical models that run on-line using the monitored traffic parameters: vehicles flow, speed, occupancy, travel times. This paper describes the innovative methodologies used for achieving these on-line estimations. The methods are already applied in the ITS system and the evaluation of their use in actual situations has demonstrated the correctness of the approach and has got to new enhancement of the estimation algorithms. For the covering abstract see ITRD E114174.
Abstract