Network Performance Degeneration in Dynamic Traffic Assignment

EVAQ is a traffic model for ex-ante evaluations of  evacuations plans. The model is still in development and it is uncertain whether EVAQ will accurately model network performance degeneration. At the same time it can be said that accurate network performance degeneration is very important for evacuations. The research of this thesis identifies that there are phenomena that contribute to network performance degeneration that are not modelled. Two important phenomena that are not included are the flow degeneration as soon as links become congested and the constraints that nodes (intersections) themselves have. Several general ideas were considered to implement these phenomena. A selection was made on the basis of accuracy and were implemented in a new link and node model.

The new models need more calculation time but produces more precise
capacity estimations. Significant changes are found for the MFD and for queue lengths (spillback). The latter now resembles results from the microscopic model VISSIM quite closely.The new node and link model are part of the Dynamic Network Loading model of EVAQ. This model has been the centre of most changes performed for EVAQ and can be used in any other Dynamic Traffic Assignment model. Furthermore, the model is theory based and can thus be used for reversed engineering and more extensive analysis of bottlenecks, also for evacuation schemes.


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