University of California Transportation Center

The successful development of Intelligent Transportation Systems (ITS) depends on the capability of incorporating a vast amount of information about the location of facilities which generate travel as well as a realistic representation of elements of the transportation network in which travel occurs. An integral part of this system is an Advanced Traveler Information System (ATIS). Such a system can be based on an innovative and comprehensive Geographic Information System (GIS). Whereas current ITS primarily use simplified transportation networks as their basis, using an object-oriented GIS allows us to provide a more realistic representation of elements of the network and the ways that people perceive them. We can represent the network by defining roads or street hierarchies and by storing environmental data as layers which can be overlain, aggregated, or decomposed at will. Storing the transportation network as a hierarchy facilitates the calculation of different paths through the network and allows the introduction of different path selection criteria. A long-run aim of ITS is to develop a real time multi-strategy travel decision support system over a multi-modal network. We examine the advantages of an object-oriented system over the link-node system in pursing such a goal. We also identify, the shortcomings of link-node technology that are overcome by using an object-oriented data model. And finally, we discuss some of the theoretical and applied implications of our suggestions.