A combined methodology for transportation planning assessment. Applicationto a case study

Traffic assignment models based on the user-equilibrium approach are one of the most widely used tools in transportation planning analysis. Resulting flows offer a static average view of the expected use of the road infrastru cture under the modeling hypothesis. This information has usually been enou gh for the planning decisions. The planned infrastructure is probably suffi cient for average demand, but time-varying traffic flows, i.e., at peak per iods, combined with the influence of road geometry, can produce undesired c ongestion that can not be forecasted or analysed with the static tools. The re is a clear case for a change in the analysis methodology such as combina tion of a traffic assignment tool, with a microscopic traffic simulator. This paper illustrates, by means of a case study, the combination of a well -known traffic assignment tool, the EMME/2 model, with a microscopic traffi c simulator, Advanced interactive Microscopic Simulator For Urban And Non-U rban Networks (AIMSUN2) with emphasis on the description of the specific in terfaces that make consistent the combination of both tools in the Generic Environment fur Traffic Analysis and Modeling (GETRAM) environment. Models for complex transportation systems should be the combination of mathematica l models and computer models, to overcome, for example, the difficulties of the integration of modeling tools. GETRAM environment has an open and flex ible computer architecture suitable for such purposes. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.