基于交通效率的城市最佳路网密度研究

Study of Urban Optimal Density of Road Network Based on Transportation Efficiency

在指出现有路网性能二元评价指标体系不足的基础上,考虑路网在通行能力和服务水平2个方面的综合性能,针对城市路网设施的断面、路段和路网3个层面提出了断面通行效率、路段输送效率和路网运行效率3个新的交通效率评价指标;并在道路面积率和交通需求分布不变的前提下,建立了4个不同密度的路网仿真分析模型。仿真结果表明:路网服务水平的可靠性随路网密度的提高而增强,但路网交通效率随着路网密度的增加具有先升后降的趋势,即理论上存在一个最佳的路网密度,使路网在容量和服务水平2个方面的综合性能达到最优。

Firstly, authors pointed out the deficiency of duality evaluation index system of current road network performances which include both capacity of road network and service level. Then, authors proposed three new evaluation indexes of transportation efficiency, ie sectional running efficiency, transportation efficiency of road segment and operation efficiency of road network on the basis of road section, road segment and road network of urban road network facilities. Finally, four simulated models of road network with different densities were built under the same conditions of road area ratio and OD pattern. The simulated results show that the service level of road network will more reliable with the increasing of density of road network, but the transportation efficiency of road network will rise first and then will drop with the increasing of density of road network continuously. So there is an optimal density of road network which makes the road network reach its optimal comprehensive performances in the aspects of capacity of road network and service level.