Evaluation Of Local Road Design And One-way Traffic Organization Based On Function Analysis

It is proposed clearly in the Code for Design of Urban Road Engineering CJJ 37-2012 that urban roads according to their importance, traffic mobility function and service function in the network can be divided into four levels, i.e. expressway, arterial road, minor arterial road and local road. Function analysis is the foundation of urban road design. The functional orientation and mathematical description of each level roads have important research significance. Local roads relate to the life and travel of urban residents closely. In the planning design and traffic organization of local road, it is not only to ensure the service function, but also to consider the traffic mobility function. At present, attention and research on local road is lagging behind arterial road system at home and abroad. The quantitative evaluation of local road function reliability based on functional analysis is especially lacking. And in the decision making process of traffic organization, it is also not enough to consider local road function.The study is supported by National Nature Science Foundation Program of Technical Evaluation and Decision-making by Stages of Urban Road Traffic Scheme Based on Function Analysis(program number: 51278468). Taking the functional description as keystone, this paper states the functional quantitative index of local road and one-way traffic organization rules to provide theoretical basis and decision reference for local road planning, construction and traffic management.Firstly, two major functions of local road are defined, which are traffic mobility function and service function. In order to realize the travel accessibility demand of urban residents, reasonable density of local road should be ensure during the stage of urban master planning. In the urban road traffic organization stage, the detour index is introduced to quantify the service function of local road. As for traffic mobility function, local road should cooperate with minor arterial road to complete traffic flow distribution rapidly. So the travel speed is very important.Secondly, the influence of one-way traffic organization on local road function is studied. Based on the implementation conditions, advantages and disadvantages of one-way traffic, the model of one-way traffic detour distance is used to evaluate urban road network efficiency. Accordingly, threshold value of detour index is determined.Finally, a regional road network system in Zhengzhou city is taken as an example, which contains one-way local road network. By the microscopic traffic simulation method, the proposed functional indexes above are used to evaluate the traffic mobility function and the service function of local road, and compare one-way street network with two-way operation. Calculation results show that one-way local roads have higher traffic mobility function than two-way streets, though, the contribution is little. Conversely, one-way operation increases travel detour distance, so that its service function decreases rapidly. Two functions of local road should be considered comprehensively in traffic organization design.