An Application of Combined Model for Tehran Metropolitan Area Incorporating Captive Travel Behavior

To overcome deficiencies of the sequential transportation planning approach, this research applies a Combined Trip Distribution and Assignment Model (CTDAM) for the simultaneous prediction. The proposed combined model can itself be reformulated as an Equivalent Minimization Problem (EMP). When applying the Evans algorithm to the EMP, the CTDAM is expected to be usable in a realistic application. The objective of this research is to compare the conventional sequential procedure and CTDAM by applying both models to a large urban transportation network for captive trip purposes. Several evaluation measures were utilized to compare the results and confirm that the proposed model can efficiently satisfy several convergence criterions. It became clear that the User Equilibrium (UE) assignment in the proposed model can be obtained relatively swifter than the Sequential Model (SM) and can be efficiently used in large transportation networks. Furthermore, the comparing results point out the performance of the CTDAM is significantly better than SM.