城市街道网单行道改造方案的评估

Evaluation of the reconstructing scheme making streets one-way

城市里随着汽车保有量的高速增长,交通日益拥挤,街道网的改造已势在必行,目前单行道改造是国内外常采用的方法。着重研究对n_1,n_2小的呈网格状的有n_1+1条东西向街道和n_2+1条南北向街道的城市道路网的单行道改造。由于网络中流动单元的随机流动,各端点之间的饱和流呈多值分布,最小饱和流发生在堵塞最严重的情况,改善网络的最小饱和流可以提高网络在堵塞最严重时的通行能力。基于网络中两端点之间的期望流通值和随机饱和流的偏方差值两个指标函数,建立了基于多重目标的评估模型以找出最佳改造方案。通过对实例的仿真研究证明了这种评估方法的有效性。

With the increasing of the vehicles in the city, the traffic jam is much more seriously. At present, the reconstructing scheme making streets one-way is often used internationally. The grid graphs consisting of n1 ＋ 1 east-west avenues and n2 ＋ 1 north-south streets, for n1, n2 sufficiently small, are studied in this paper. It is possible to find multi-scenarios reconstructing the grid graphs. The emphasis on how to evaluate the optimal reconstructing scheme. For the sake of the stochastic flow in the network, the saturated flow between the two vertexes is multi-value. In the case of the most seriously traffic jam, the saturated flow is minimum. Adding the minimum saturated flow could improve the traffic performance. Based on two indices of the expected flow and the bias-variance of the stochastic saturated flow between the two vertexes, this paper presents an evaluative model having multi-objects to solve the optimal reconstructing scheme. Finally the validity of this evaluation is illustrated with an example.