Study On The Diffusion And Models Of Urban Arterial Road Congestion

Traffic congestion has been increasingly conspicuous recently years, so it'svery necessary to study on the related theory and models of traffic congestion. Asthe core content of congestion management, the study on the diffusion and modelsof traffic congestion has important significations. The research not only providestheory basis and methodology for traffic congestion counter-measures, but alsoenhances the efficiency of congestion dispersal strategies, so it can save thevaluable time of traffic congestion dispersal, improves the utilization efficiency oftraffic management resources, induces the adverse influences of traffic congestion.This dissertation based on the sub-item "The Study on Theory andMethodology of Prediction and Prevention of Traffic Congestion", which is anelement of National Science Foundation Item "The Study on Key Theory of UrbanRoad Network Dynamic Traffic Management and Control and SimulationTechnology" (No. 500338030). The purpose of this dissertation is to constructcongestion estimation models from time and space. This dissertation proposes themethod for identifying the diffusion of congestion, and builds new estimationmodels by using queuing theory, traffic wave, statistics analysis and microscopicsimulation.This dissertation first puts forward the necessity and feasibility of the researchbased on actually status, obtained the different characteristics of recurrentcongestion and non-recurrent congestion, these are the basis of constructingcongestion estimation models. And then, this dissertation studied the congestionestimation models which based on fixed detectors and floating cars, established theestimation models of congestion duration, queue length and delay, analyzed theprecision of these models and the veracity of describing congestion diffusion. Inorder to compare the precision of these data collection methods, this dissertationanalyzed the precision of CEMFD and CEMFC of the same congestion. Becausethe space between fixed detectors obviously influences the veracity of estimationmodels, this dissertation also designed the detectors space schemes and the sampleproblems of floating cars. A complete object-oriented computer program inVISSIM has been used to simulate the different scenarios. The results of thesesimulations are used to obtain the optimal scenarios. This dissertation has sixchapters, in which the 2nd chapter, 3rd chapter and 4th chapter are the focus chapter.The 1st chapter introduced the source of research work, pointed out thenecessity and meaning of this study, and discussed the domestic and internationalpresent situation and existent problems, carried out brief introduction for the majorcontents, and designed the technology routes of this dissertation.The 2nd chapter interpreted the diffusion of recurrent congestion andnon-recurrent congestion, which based on analyzing practical and simulated data,described the time and space diffusion by using congestion duration and queuelength, and analyzed the distinct diffusion characteristics of different congestion.These theories provided the foundation of constructing estimation models.The 3rd chapter put forward congestion estimation models based on fixeddetectors, for whose basis was the analysis of congestion diffusion, constructed theestimation models based on the distinct characteristics of congestion. Finally, the3rd chapter validated the precision of models by using practical and simulation data.The 4th chapter put forward congestion estimation models based on floatingcars, for whose basis was the analysis of congestion diffusion. Because the floatingcars can gather the journey time of any section road, thereby measured thediffusion of congestion, so any type congestion wasn't different from each other. Atlast, this chapter analyzed the precision of CEMFD and CEMFC of the samecongestion.The 5th chapter studied the detectors space schemes and the sample problemsof floating cars. A complete object-oriented computer program in VISSIM wasused to simulate the different scenarios. The results of these simulations were usedto obtain the optimal scenarios.The 6th chapter summarized the major research of this dissertation, pointed outthe existing problems, and the problems that need to be further studied in thefuture.