城市群环路的双目标规划模型

为了确定城市群环路的合理半径及其环带服务宽度,提出了以走行距离和路径总阻抗为目标函数的双目标规划模型.其中,走行距离函数考虑OD点3种相对位置情况,利用d ijkstra算法求解;路径总阻抗函数采用预算约束的离散交通网络设计的双层规划数学模型,用分枝定界算法求解.研究表明,城市群环路所服务的对象,主要是夹角小于90°的OD对.以成都市都市圈路网为实例验证了模型的可行性.

Two-Objective Programming Model of Ring Road around Urban Agglomeration

A two-objective programming model was proposed to determine rational radii and service widths of urban ring roads.In the model,trip distance and general path impedance were taken as the two objectives.Three situations in terms of different OD pairs are considered in the trip distance function,and the model is solved with Dijkstra algorithm.The general path impedance function is expressed with a bi-level programming model of discrete traffic network with budget constraint,and the model is solved with branch and bound algorithm.The analysis results show that urban ring roads mainly serve the OD pairs with an angel less than 90 degree.The ring roads of Chengdu,the capital city of Sichuan Province,China,were taken as an example to show the feasibility of the proposed model.