Transit service is vital to the ongoing urban development of many transit-oriented metropolis. Design of a transit system is a complex decision process which involves interests from multiple parties. Traveler's desire of a quick, direct but cheap service of good quality often conflicts with the profit-making nature of private operators. Transit network design, similar to other transportation network design problems, is combinatorial in nature. However, the former differs in that it needs to consider as well various issues like transit transfer, load percentage, and redundant routes. Indirect service, where in transfer is necessary, could be a cost-effective solution from the perspective of a transit system provider. However, too many transfers would make the routes less attractive in a...[ Read more ]

Transit service is vital to the ongoing urban development of many transit-oriented metropolis. Design of a transit system is a complex decision process which involves interests from multiple parties. Traveler's desire of a quick, direct but cheap service of good quality often conflicts with the profit-making nature of private operators. Transit network design, similar to other transportation network design problems, is combinatorial in nature. However, the former differs in that it needs to consider as well various issues like transit transfer, load percentage, and redundant routes. Indirect service, where in transfer is necessary, could be a cost-effective solution from the perspective of a transit system provider. However, too many transfers would make the routes less attractive in a competitive market. On the other hand, providing more direct routes may result in low passenger loads and service redundancy that adds to road congestion, especially in the downtown area.

Previous studies mainly considered networks of a single transit mode. In the reality of multi-modal network, cooperative or competitive interactions between co-existing transit modes further complicate the problem. This leads to the notion of an integrated transit network design. This study explicitly considers the variety and extent of these interactions in a multi-modal network. We develop a systematic 3-phase methodology for the integrated transit network design, focusing on the integration of transport modes via possible mode-to-mode transit transfers. Inter-route and inter-modal transfers are addressed through the assignment on the State-Augmented Multi-modal (SAM) network, a platform that automatically incorporates different transfer rules and handles non-linearity of travel cost frequently encountered in transits. Furthermore, this design framework surpasses others in performing stochastic user equilibrium (SUE) network assignment with congestion effect, which is argued as being more robust in modeling the choice of transit users. An illustrative example is included to demonstrate the design procedures.