Optimization of Conventional Bus Routes in Overlapping Bus–Rail Corridors with Urban Rail Transit

Overlapping bus–rail corridors between conventional bus lines and urban rail transit are common in integrated public transportation systems. When existing bus routes highly overlap with newly operated rail transit lines, redundant services may reduce resource utilization and increase operating pressure, while inappropriate route adjustment may negatively affect the travel experience of original bus passengers. To address this problem, this paper proposes a constrained passenger-time-oriented optimization model for conventional bus route adjustment under rail transit operation. The model evaluates passenger travel cost while jointly considering passenger flow demand, service continuity, route compactness, and the accessibility requirements of original bus passengers. Based on the proposed model, a bus line generation algorithm is designed to obtain feasible and compact adjustment schemes for co-linear bus segments. The methodological applicability of the proposed method is evaluated through a simulation experiment, and its practical applicability is illustrated through a real-world case study of Xiamen Bus Line 27. The results indicate that the proposed method can reduce passenger travel cost and alleviate redundant competition between conventional bus and rail transit services, while maintaining acceptable service continuity for existing passengers.