Spatio-temporal Model Of Traffic Status Based Methods For Urban Road Network Performance Analysis

Urban traffic is a distributed, people-participating, time-variant complex system with the characteristics such as dynamic, random and so on. The traffic characteristics of the system vary because of different national situations. It is proved at home and abroad over the years that to solve traffic problems is not only costly, serious environmental-polluted but also limited in the effect of reducing traffic congestion and other problems relying on the construction of road infrastructure and traditional traffic management simply without the guidance of advanced theory. All the factors above urged the Advanced Traffic Management System (ATMS). Real-time information is the core of ATMS, and the road network performance evaluation is the best way to provide it. Firstly, this paper describes the purpose and significance of carrying out the performance evaluation of road network, and then points out the problems still existing in the research through synthesizing the results of the performance evaluations of the road network at home and abroad. The problem lies in the following two parts:(1) The existing methodologies take the overall performance evaluation of road network without considering the difference of the traffic flow's characteristics of road network in different regions that the results obtained can not have much practical significance.(2) In the previous research, the traffic condition assessment of road network are based on the dynamic information of traffic parameters such as travel time, average travel speed, intersection delays, queue length and so on, ignoring the use of static information including road length that characterizes importance of various sections of the road network.Based on the analysis of the problems above, this paper proposes a method that bases on the extraction technology of traffic flow's characteristic parameters. By researching in the dynamic technology of sub-area division and temporal-spatial model of regional transport state, finally we propose the way of evaluation of Network Performance. This paper is divided into six chapters, of which the second, third, fourth and fifth chapter are key ones, the third, fourth and fifth chapters give the core of the paper, the first and the sixth chapter separately introduces the meaning , background , ideas and the summary, outlook . The key to this study includes the technique of regional traffic state classification based on fuzzy synthetic judgment, the establishment of temporal-spatial model of regional transport state, and the analysis of network performance lies as follows:(1) The technique of regional traffic state classification based on fuzzy synthetic judgment.Based on the extraction technology of traffic flow's characteristic of intersections and regions , we select the maximum phase saturation, the maximum average queue length ratio (ie. the ratio of the intersection import's queue length and the section's length )of the intersection import and the average speed of the section as the characteristic quantity of road traffic state's comprehensive evaluation and get the evaluation factors set by deciding the membership function of the three parameters ;Then we take fuzzy comprehensive evaluation by selecting fuzzy weighted average-type function and the definite method of each factor's weight based on expert experience, and get the evaluated set; Finally the final result of fuzzy comprehensive evaluation of sub-area traffic state is given based on the single factor decision-based de-fuzzification process .(2) The establishment of temporal-spatial model of regional transport state considering the characteristics of the two parameters -travel time and the length of the section- synthetically, we change the calculation of travel time into the calculation of average speed by the dimensionless process and get the parameters of the sections'state. Through the introduction of sections'state parameters and congestion threshold in the adjacency matrix that on behalf of the topology of road network, we get the connection matrix of the sections'state to describe the real-time connectivity of the various sections of the road network(3) The analysis of network performanceBy virtue of the analysis of accessibility between junctions and connectivity of sections, we can describe the access convenience between different intersections and the distribution of non-connected sections in road network , describing the road network performance approximately ; To further understand the sections'traffic conditions, we can take time series analysis of a section in one direction, a section of certain line or even a section in the region, and mine the hidden information of the traffic state data deeply to provide information support for improving the level of traffic management and control.Based on the extraction technology of traffic flow's characteristic parameter , this paper selects the syndicated assessment characteristics of regional traffic state ; Virtue of the dynamic technology of sub-area division under traffic control system, ,we take the analysis of network performance that bases on temporal-spatial model in three aspects including the analysis of accessibility between junctions , the analysis of connectivity of sections and time series analysis of traffic state in the advanced way of statistical methods ,artificial intelligence and so on ,All those above provide the information base for the implementation of the district sub-areas'optimal control strategy under different conditions improving the transport efficiency of network , people's travel environment and the quality of travel.