Integrated Decision Model of Mode, Line, and Frequency Reflecting Changes in Travelers’ Behaviors

Decision-making for public transit planning includes a variety of choices. Among them, the choices of mode, line, and frequency are key elements that influence travel demand; thus, the previous literature has focused on developing models for determining these elements separately, even though mode, line configuration, and frequency should be determined simultaneously. Doing so is essential because mode selection provides the constraint conditions that are applicable for line configuration and decisions concerning the frequency of operation. Furthermore, line configuration and frequency also influence capacity and speed, which are closely related to the selected mode. Therefore, the aim of this paper is to develop a decision model that integrates mode, line, and frequency for a new transit line. The model has a bi-level structure in which the upper level of the model is formulated to determine mode selection, line configuration, and frequency, whereas the lower level of the model is formulated to determine mode share and link flows reflecting travelers’ behaviors related to choices of modes and routes. An application of the proposed model is presented using a test network. The results of this application show that the proposed model performs better than the existing methods that are used in the pertinent literature. The model simulates realistically the influence of a new transit line on its surrounding network by reflecting changes in travelers’ behaviors according to the transit line’s construction, and it also provides a theoretical basis for the evaluation of the feasibility of the planned investment in a new transit system.