Microscopic Traffic Simulation Of Priority Intersection

With the rapid development of economy and society, traffic infrastructuresrestriction has been more and more obvious. The restriction is showed that trafficjam is increasingly prominent and traffic block brings out air pollution and trafficsecurity problem.Urban road network are composed of links and intersections. Vehicle turningcan cause conflict, converge between vehicles which makes traffic flow is verycomplex at the intersection. Traffic flow behavior at the intersection is closelycorrelated with whole urban traffic, especially for some key intersections, whichcan be factors affecting urban traffic function. However, it is important to mastertraffic behavior character to solve the problem. Traffic simulation can representtraffic behavior and work as an important means and tool to management, controland optimize traffic system. Micro traffic simulation system can evaluate andanalyze individual vehicles movement at intersection. Improved traffic conditioncan also be attained in short time. As for different parameters, traffic simulationsystem can explain traffic congestion and effect of conditioned traffic managementand control measures. More importantly, micro traffic simulation can solve the casein which some traffic management and control measures are difficult andimpossible to carry in the field.Based on above study background, this dissertation investigates micro-trafficsimulation model at priority intersection. Object of this dissertation is to investigatetraffic behavior and develop micro-traffic simulation model at priority intersectionin China. Models can be used to evaluate effect of intersection design project andmanagement measures on traffic, make reasonable traffic management policy andintersection design project, improve capacity and service level of intersection andprovide the basis to set up the traffic light.Main content of this dissertation is as follows:Chapter one, introduction, mainly introduce study background, object,meaning, and main content and technique route of this dissertation.Chapter two, analyzes traffic flow character at priority intersection,investigate traffic conflict type and forming reasons. Cross intersection, Tintersection, roundabout intersection traffic behavior, traffic right and trafficconflict point. HCM accepted gap theory is presented. According to study objectand means, accepted gap is classified. Estimated means of critical accepted gap aregiven. In theory, affection of driver behavior on critical accepted gap is describedand interaction between driver behavior and traffic flow is also presented.Chapter three investigates micro-traffic simulation modes at priorityintersection. Different vehicle generation models are developed to reflect thedifference in traffic volume between major road and minor road. Analyze vehiclemovement character in different stages, determine acceleration model, decelerationmodel and car following model. Analyze vehicle lane change character and intent,choose Hidas as lane change model. According to state of vehicle movementthrough intersection, driver decision model is built. Performance of measures atpriority intersection is also studied, which include queue length, delay and capacity.Chapter four includes data collection and model calibration and validation.Collect major and minor road headway,determine headway distribution character.Use the likelihood estimated means to acquire critical accepted gap. Analyzecharacter of micro movement data which are used to calibrate and validate models.Means to collect data of vehicle movement are summarized. With software VEVID,collect vehicles movement data near the intersection. According to character ofcollected data, choose generalized least square to calibrate models. Analyzeaffection of speed, space and head way on calibrated results. Choose space asmeasure of performance to calibrate and validate car-following model presented inthis dissertation with generalized least square.Chapter five applies models in TPSS simulation platform development. First,introduce TPSS framework, function and data structure. Models developed areapplied in TPSS. At last, choose T priority unsignalized intersection in Changchun,and apply TPSS, VISSIM and CORSIM to simulate traffic flow. Comparesimulation data with field data, and analyze the difference between them. Theresults prove the validation of models in this dissertation.Chapter six is the summary. The main research content is summarized and theproblems which need to be researched more deeply are presented.Main contribution of this dissertation is as followed:1. Study urban traffic flow behavior character. Analyze the interactionbetween driver behavior and traffic flow, which provides the basis for developingmicro-traffic simulation models at priority intersection.2. In video collection means, acquire vehicle moving data in differentmovement sate near the intersection. With Generalized Least Square, calibrate andvalidate car-following model.