Aedramework for integrated dynamic analysis of travel and traffic.

This paper reports on the work carried out by the FRIDA consortium in developing and testing a framework for an integrated dynamic analysis of travel and traffic. Such a framework deals with traffic behaviour modelling by analysing traffic conditions, assigning - if necessary - RTI (Road Transport Informatics) measures to improve the analysed situation and simulating the likely effects of RTI on both travel behaviour and traffic conditions. These actions are designed within three subsystems, dealing with (i) travel behaviour (subsystem A), (ii) individual on-the-road behaviour (subsystem B), and (iii) collective on-the-road behaviour (subsystem C). The framework essentially aims at describing and specifying the modelling of the sub-systems, their interaction within the framework and their integration within the telematic environment. These sub-systems are treated as sub-modules of one supervising system (administrator). The interfaces between the administrator and each sub-system play the role of - and are modelled as - regulators. It is maintained that synergy must exist between the sub-modules and that they must be coordinated. This major requirement implies the need for compatibility at several levels such as the information exchange level. In order to satisfy the need for coordinated treatment linkages between the sub-systems have been established. A major task reported in this paper refers to the modelling implications of these linkages. This process is addressed and modelled at two levels: at the microperformance level (as in subsystem B) and the macroperformance level (as in subsystem C). Such a distinction is conditioned by the content and properties of the distributed information (e.g. level of detail, time interval, means of communication and the property of being active or passive) and it also has implications on the model types which are selected to describe the various transportation system components. FRIDA also focuses on the testing of the framework. This is achieved by a prototype consisting of existing but specifically integrated models. Supervision is achieved through specially designed graphics routines.