老城区交通微循环的双层规划模型

老城区道路街巷网络密集，利用交通微循环可以缓解交通干道的压力，提高区域路网的承载力和可达性。以干路饱和度和街道级交通指数为优化目标，支路不拥堵为约束条件，构建上层模型，采用用户均衡交通分配与借助Tran CAD求解下层模型，构建老城区交通微循环的双层规划模型，并通过实例说明了模型的建立与求解过程。

Bi-level Programing Model of Traffic Microcirculation for Old City

The old city has a dense network of roads and lanes. The utilization of traffic microcirculation can relieve traffic pressures on the trunk roads and improve the bearing capacity and accessibility of the regional road network. Taking the saturation of trunk roads and traffic index of street level as the optimization objective and the non-congestion of branch roads as the constraint condition, the upper-level model is built. The lower-level model is solved by using the equilibrium traffic assignment of user and in virtue of TranCAD. The bi-level programming model of traffic microcirculation is established for the old city. An example is given to illustrate the process of building and solving the model.