| China is now in the stage of high-speed development both in economy and society. The size of city is constantly enlarged, the number of vehicle rapidly is increasing and the demand of traffic is aggressively improved. China's traffic problem happened in many cities under the situation of the shortage of transport supplements. Traffic congestion results in the decrease of economic vitality of city, the increase of urban living cost, and exacerbates traffic safety situation and urban environment quality. Faced with this situation, transport problems, such as making the transport developing strategy and plan of city of China, building the sustainable developing integrated urban transport system, and laying the foundation for building a moderately prosperous society, should be solved as quick as possible. Road network reliability is an important indicator of traffic planning, therefore, the research on reliability of urban road network has important theoretical and practical significance.Domestical and international status quo of road traffic capacity, road reliability and research of urban traffic network design is detailed elaborated, the relative basic theory systematically is studied, and proposed the method of combining transport network bottleneck identification and the method of quantitative analysis of section reliability is proposed, and the traffic flow in the research field in a way of full capacity is simulated by ExSpect software.After the detailed elaboration of the relative basic theory of combinational network and the theory about reliability, based on the combination of network, the concept of combined transport network is advanced. Based on the study of discussing the capacity of the road, the difference on the definition of standard of the degree of road congestion at home and abroad, and the characteristic of crowded traffic flow are analyzed, which is theoretical groundwork for analyzing the the raffic flow characteristics in the course of the solution of the road network reliability.The bottleneck of single-source transportation network is identified by using max-flow min-cut theorem, which considered the minimum cut is the key of affecting network traffic. In other words, this part is the smallest place throughout the network capacity, but it determines the maximum traffic capacity over the network, that is, as long as finding the minimum cut network traffic, can we receive maximum flow of the network. If we want to provide the entire traffic capacity of the network, we must rebuild from the minimum cut parts. The process of finding the maximum flow of the network's minimum cut can be divided into two steps, one is to look for the process of augmenting path, and the other is the adjusting process of the flow of augmenting path. Based on the above two processes, the way of searching for the maximum flow minimum cut method in detail is discussed.Generally speaking, transport network is a multi-source network, which means the generation of traffic flow has many starting points and terminal points. At this moment, this problem can be solved by adding a virtual starting point and a virtual terminal point, so that the original multi-source network can be transformed into a single-source network. And then the happening location of the multi-source transport network bottleneck can be found, according to the identification theory and method of the combined transport network. Among the analyses of the cases of combined transport network bottleneck's identification, Changyi district traffic network is chosed as the research object, studying the identification of transport network bottleneck, of which Songjiang Bridge, Qingyuan Bridge, Longtan Bridge as its starting points, and Jiangwan Bridge, River City Plaza, East Liberation Street interchange with Jilin Street as its terminal points .According to the data of road capacity in the research field, some sections which transport network bottlenecks happened have been identified, including Jilin Street (Yan'an Road - East Wusong Road), Zhongxing Street (Yan'an Road– Tongjiang Road), Sichuan Street (Yan'an Road - Tongjiang Road), Liberation North Road (Yan'an Road - East Wusong Road) and Songjiang Road (Yan'an Road - East Wusong Road).After the relation among the three traffic flow parameters is analysed, that is, traffic volume Q, traffic speed V, traffic density K, and the relation between traffic speed and traffic density, the quantitative definition method of section reliability is proposed, whose parameters are traffic speed V and traffic density K, that is, section reliability. In this definition, focus on some road, its speed and block density has been known, if the velocity V and the density K can be known in a given time, then the reliability of this section can be calculated. According to research data, research shows that all the morning peak reliability of bottleneck section are lower than other time, the early peak section reliability of Monday is lower than that of Tuesday, which testified the validity of the definition of reliability. Example result shows that the lowest point of reliability, which happened in evening peak of North Liberation Road in Januraly 1, 2010, is 74.14%, so the current road network meets the reliability requirement of transportion. Based on the summarized experiences about traffic design at home and abroad, the traffic conditions are tried to improve by increasing road network density. And a project about the urban transport network of Changyi District Jilin City is proposed, focusing on the transport bottleneck of transport network in Changyi District, Jilin City, in which Songjiang Bridge, Qingyuan Bridge and Longtan Bridge as its starting points, and Jiangwan Bridge Jiangcheng Square East Liberation Street interchange with Jilin Street as its terminal points. Using ExSpect software, this research simulates network capacity through full load operation of traffic flow, whose objects are the current transport network in Changyi District, Jilin City and the transport network project proposed in this paper. The research shows that compared with the existing traffic network, the project in this paper can reduce the average running time of traffic flow by 45.77 seconds, increase efficiency by 7.62% and increase traffic flow stability by 27.04%.In order to apply the research results into computer, the construction technology of digital urban road network is studied. Taken the characteristics and advantages of the GIS technology and the need of the research project into consideration, the key technology in digital city-road network construction is studied deeply, mainly are the conversion technique of traffic information data format, the dynamic segmentation technique and the discrimination algorithm of urban transportation infrastructure location. the conversion method from CAD to GIS based on SuperMap is studied, and by using this method converts GIS into Shape forms successfully according to the CAD data offered by the traffic police detachment in Jilin City, due to the different advantages and characteristics between CAS and GIS, and also the practical need of CAD data offered by the traffic police detachment in Jilin City. And this method provides basic data for city-road network construction. Dynamic segmentation technique can appropriately express traffic characteristics of one-to-many relationship and improve data processing ability significantly by describing the relationship between different data formats. Moreover, a further step was taken into the theoretical analysis and the algorithm description, based on the study of the dynamic segmentation technique, and provided the query of transportation infrastructure with dynamic segmentation structure form, Geodatabase model, etc. A new algorithm was given in this paper to test the relationship between a spot and polygonal position based on the ray research. The algorithm first convert polygon to convex polygons and then determine the location relationship between the spot and the original polygon by judging the location relationship between the testing spot, the converted polygon and the enclosed polygon. This method has taken all kinds of cases, where the spot is in, on (including vertex) or out of the area, into full consideration. As a result, it is a new method for judging the location relationships between a spot and polygon of all shapes.
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