An Extended Traffic Assignment Model with Applications to Two-Way Traffic

A transportation network is considered. The traffic demands associated with pairs of nodes and the traveling cost functions associated with the links are assumed given. An extended traffic assignment model where the traveling cost on a link becomes a function of the entire flow pattern in the network is introduced. The model appears particularly suitable for application to networks containing two-way streets, in view of its capability of taking into account delays to travelers of one lane caused by traffic on the opposite lane. It is also suitable for application to urban transportation networks, where the travel time on a link depends crucially on the delays occurring at the intersections. This in turn depends on the traffic volumes on the intersecting links. The concepts of system-optimizing and user-optimizing traffic patterns are studied. Moreover, an algorithm for the construction of the above patterns is presented and applied in an example.