关键词: 城市交通, 联合优化, 连续近似, 双模式公交, 环形放射状网络, 需求响应公交

Abstract: This paper focuses on the unbalanced utilization of network resources and long travel time of passengers for the conventional transit network during the ring-radical cities' expansion and proposes a modal network structure with a hierarchical layout of conventional transit and demand-responsive transit. Based on the continuous approximation method, this paper uses a mixed-integer program to minimize the sum of expected passenger cost and agency costs. A deterministic mode split and route choice model is embedded and cost components are derived based on passengers' groups. Then, decision variables such as the stop and line spacing of the conventional transit and the headway of bi�modal transit systems are optimized and a hybrid heuristic is proposed to solve the problem. At last, to verify the effectiveness of the designed network, a case study is conducted on a real-world ring-radial network within the fifth ring of Chengdu City. The results indicate that compared with the conventional transit network, the proposed system can reduce passenger costs by approximately 18.37% while effectively reducing operating costs by approximately 4.97%. The proposed system can reduce the construction cost by 31.85%, and reduce the travel distance by 24.36% for conventional buses. System cost decreases exponentially with the increase of average passenger flow density and the values of key design parameters under different conditions can be provided through the proposed method.

Key words: urban traffic, joint optimization, continuous approximation, bimodal transit, ring- radial network, demand responsive transit