Modeling and optimization of an oversaturated signalized network

This paper proposes a dynamic method to control an oversaturated traffic signal network by utilizing a bang-bang like model for the oversaturated intersections and TRANSYT-7F for the undersaturated intersections. An algorithm entitled the maximal progression possibility determines the optimal operating procedure by searching for progression routes and smoothing the transition between successive control cycles. The proposed model integrates two different operating procedures: saturated and undersaturated. The method was tested in a network comprising a core area of 12 initially oversaturated intersections that are surrounded by thirteen undersaturated intersections. It was concluded that the proposed method is much more effective in relieving congestion in a network than TRANSYT-7F. Since TRANSYT-7F is not suited for oversaturated network signal timing control, it can be mitigated through integration with the proposed model. (C) 2004 Elsevier Ltd. All rights reserved.