Further development of SAMPERS and modeling of urban congestion

The need to more precisely represent the consequences of congestion mitigation policies in urban transport systems calls for replacement of the static equilibrium assignment by DTA in the integrated travel demand and traffic assignment models. Despite of the availability of DTA models and despite of the conceptual clarity of how such integration should take place, only few operational model systems have been developed for large-scale applications. We report on replacement of the static traffic assignment by two different DTAs in the four stage demand model for the Greater Stockholm region: the macroscopic analytic Visum DUE and microscopic simulation Transmodeler. First results show that even without systematic calibration the DTA is in reasonable agreement with observed traffic counts and travel times. The presented experiments did not reveal striking difference between using macroscopic and microscopic assignment package. However, given the clear trend to microscopic modeling and simulation on the travel demand side, the use of micro-simulation-based DTA package appears more natural from system integration perspective.