A Study on Vehicular Queue Models
|Course||Traffic Information Engineering \u0026 Control|
|Keywords||Urban Roads Signalized Intersections Traffic Congestion Time-Space Characteristics Queue Length Start-Stop Waves Kinetic Characteristics Queue Location|
The amount of the automobile ownership is unceasingly augmenting that bringing forth an international problem, namely, traffic congestion which has been noticed extensively. The problem is troubling all cities to different extents. It has gradually become one of the primary bottlenecks which blockage social and economical development. Traffic congestion has been a critical issue to be considered for cities all over the world.Relied on the Key Program of National Natural Science Foundation“Research on key theories of dynamic traffic management and control and simulation technique for urban road networks”and the project“Organization optimization and control of urban traffic system”of the National Basic Research Program (973 Program) of China“Study on the basis scientific problem of traffic congestion and jam bottleneck in big city”, vehicular queue length and location models are mainly discussed in the paper, and their effects on a single section. The paper is composed of six chapters. Chapter Two, Three, Four and Five are the focus in the paper, with Chapter Three and Five as the crux. The key parts of individual chapters are as follows:Chapter One Firstly, research background is introduced with the analysis of traffic congestion and vehicular queue, and the indication of research intention and meaning of the paper. Then, in light of three aspects as microscopic traffic flow analysis, macroscopic traffic flow analysis, microscopic and macroscopic traffic flow integrated analysis, domestic and overseas research achievements on the theme are summarized, which duplicate the vehicular queue phenomena and the effect resulted from vehicular queue on the road network. Finally, the contents of the paper and the chapter scheme in the paper are clarified.Chapter Two First, the domestic and overseas research achievements about the methods of describing road network structure are summed up; in which, the deficiencies are pointed out. Then, with the graphics theory as theoretical basis and the actual problems as the objective, the functions describing signal timing (including the description functions of phase parameters and period of time parameters), the functions of describing road characteristics (including the description functions of road network structure and intersection partition) and the functions of describing traffic flow characteristics (including the description functions of traffic flow existence and traffic volume) are built respectively. Therefore, the correlative time-space functions of traffic flow (including traffic flow and phase correlative function, and traffic flow and lane correlative function) are constructed. The functions are exemplified in the paper.Chapter Three In the first section, three aspects of probability method, accumulative curve method and shock wave analysis are classified by generalizing domestic and overseas research achievements about the vehicular queue models. Merits and faults are analyzed in detail. In the second section, the two-fluid characteristic of traffic flow is described in accordance with the two-fluid theory after analyzing the actual forming process of queue in traffic flow. In the third section, the equivalent queue length model for a single-lane segment is built on the basis of the three-detector principle and the average equivalent queue length model for a multi-lane segment is educed further after the two-fluid characteristic of the stronger congested traffic stream is analyzed. The parameters calibration and the accumulative vehicle number acquisition methods are explained with model validation by examples from simulation software. In the forth section, the equivalent queue length model for a single-lane segment are revised to describe the weaker congested traffic stream. The traffic survey scheme and the parameters calibration method are designed, and the revised model is validated by the survey data from the typical intersection in Changchun City. To further discuss the equivalent queue length models, the average equivalent queue length change ratio models for a single-lane segment and a multi-lane segment respectively are developed by applying differential calculus and validated by simulated data in the fifth section.Chapter Four The maximum equivalent queue length model is given on the basis of the equivalent queue length model for a single-lane segment. The effect of the arrival vehicular volume during the red light, the blocked vehicle number at the beginning of red light, the cycle timing, the green ratio and the length of road segment on the maximum equivalent queue length are analyzed separately. They are named as the traffic flow, time and space characteristics of the maximum equivalent queue length. The material description method is to analyze the change principle of the curve bunch formed by one variable and the maximum equivalent queue length under the condition of the other variable changing when there is no change in the rest three variables. Finally, the sensitivity of the maximum equivalent queue length to every parameter is solved by using partial-differential operation on the basis of the concept of sensitivity and the sensitivity priority grade of each parameter is analyzed further. Chapter Five First, the domestic and overseas research achievements about the traffic wave, especially, start-stop waves, are introduced and the problem of the existing models is analyzed in detail. In the second section, three kinds of the start wave and stop wave models, namely, the Greenshields start wave and stop wave model, the Greenberg start wave and stop wave model, and the general start wave and stop wave model are summarized followed by the basis traffic wave model. In the third section, the kinetic start wave model and the kinetic stop model are built individually on the basis of analyzing the start process and the stop process at signalized intersections respectively. The uniform model for start-stop waves is obtained according to the relations of traffic flow parameters; and the model can be educed from the general start wave and stop wave models which is proved. In order to validate the built models, the traffic survey schemes and the parameters calibration methods are designed. The models are validated by survey data from the typical intersections in Changchun city and the results are satisfactory. The formation and change principle of the traffic jam segment are described by cognizing the start-stop waves in the forth section. When regarding the time-space description functions in road network and the kinetic model for the start-stop waves as the theoretical basis, the queue end location function, the queue head location function and the queue length determination function are given respectively. They are unified as the queue location decision model. Finally, the effect resulted from vehicular queue is analyzed by applying the queue location decision model.Chapter Six The obtained improvements and the innovative productions are summed up. The issues to be discussed further are put forward. The acquired primary achievements are as follows: (1) Describing the two-fluid characteristic of traffic flow according to the two-fluid theory; (2) Building the equivalent queue length models on the basis of the three-detector principle; (3) Giving and analyzing the sensitivity of the maximum equivalent queue length; (4) Establishing the kinetic model for start-stop waves at signalized intersections according to the kinetic equation and solving the problem that traditional models are not easy to apply in engineering practices; (5) Constructing the queue location decision model and providing the theoretical foundation for analyzing the effect resulted from vehicular queue in road network.