Research On Basic Traffic Signal Warrant For Intersections

Intersections are significant joints of road network and throat of traffic. Various vehicles and pedestrians realize influx, turning and passing in this region, mutual interference of each other is very serious; produce many confluence points, interleaving points and conflict points. The capacity at intersections reduce greatly than the road sections, and the intersections are accident happening easily places, as the interleaving operation of vehicle flow, non-motor vehicle flow and pedestrian flow. Therefore, intersections are the concentration point of contradiction and the source of traffic problems. Consequently, solving the problems of intersections is the crux of urban traffic.Signal control is effective method for improving traffic capacity and mitigating traffic congestion at intersections. Setting signals reasonably can improve traffic capacity, reduce traffic conflicts and decrease the frequency of traffic accident, whereas illegitimate setting may lead to the increasing of average vehicle delay and accident number. Accordingly, signal control has certain scope of application, setting signal has specific warrants. America occupy the international leading position on traffic signal warrant, Manual on Uniform Traffic Control Devices made by Federal Highway Administration stipulates the warrant of various signal, which are cited widely by other contrives. Our country issues and implements national regulation of setting signal, and the Critical Volume warrant basically adopt American standard. However, the difference of traffic condition between china and America causes this warrant is limited greatly in concrete application, hence, this paper proceeds further study on traffic signal warrant according to our national conditions.The first part of this thesis introduces the research background of this text, and analyzes the purpose and significance of this research. Meanwhile, this part establishes frame structure of the paper based on the review and summary of research results both at home and abroad, thus lays a foundation for subsequent research work.The second part of the thesis firstly introduces various traffic signal warrants and establishes the process of signal setting. Then on the basis, this paper clearly puts forward the research emphasis, and points out the connotation and importance of basic warrant. Finally, this part introduces the selection of motor vehicle flow in basic warrant and research ideas and methods of this paper.The third chapter demonstrates the feasibility that regarding the multiple traffic flows as one analyzing with probability theory, then establishes the model of the vehicle average delay based on the gap acceptance theory and queuing theory. Further more, through comparing the average vehicle delay under condition with traffic signal, the paper obtains the critical volume curve of warrant for setting signal under different critical gaps of three common no signal cross patterns by choosing the lower delay as the optimal control patter according to traffic efficiency. At last, this part analyzes these factors which affect the basic traffic signal warrant for intersection under Major/Minor road condition, such as critical gap, following-time, saturation flow rate, phase lost time and so on.The fourth part discusses the operation law of vehicles at equal weight intersections firstly, then improves the model of Motorcade Analysis Method, basing on the gap acceptance theory and queuing theory, through introducing the lost time of saturation releasing and the coefficient of traffic flow asymmetry. Further more, the model of vehicles average delay at equal weight intersection is proposed. Moreover this paper obtains the critical volume curve of warrant for setting signal by choosing the lower delay as the optimal control patter according to traffic efficiency and . Finally, through field survey about the influence parameters of traffic signal warrant, the model of vehicles average delay at equal weight intersection proposed in the fourth paper is showed high precision, Then on the basis of this, this paper analyses the necessity of signal setting at various periods in view of theoretical analysis and practical investigation, and indicates the correctness and applicability of basic traffic signal warrant at equal weight intersection.The last part of the paper gives a summary of the full text, and reviews the research contents and progress of this paper, finally, puts forward the issue to be further explored.