The Urban Transportation Modeling System (UTMS) is a set of procedures used by transportation planners to predict the volume of traffic that will flow through a network, and how the traffic is routed. This paper will focus on the final component of UTMS, traffic assignment, which assigns the traffic flows to actual routes in the network.
In this paper, two composite models which model both User Equilibrium and System Optimal assignments are presented. The composite models are solved using the GAMS (General Algebraic Modeling System) software, a powerful mathematical programming tool. The first model was based on Beckman's Formulation, (Beckman, MacGuire, Winsten, 1956). The second model was developed by the author and utilizes some unique features of the GAMS software in order to solve the problem of User Equilibrium. Finally, the results of the example problem are used to develop general conclusions regarding the applicability of the model, as well as areas of future improvement and research.
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