Methods For Arterial Coordinated Control Of Signal Intersection Under Dissymmetry Flow

Along with the development of society,there are more and more special events conducted in cities.Special event can gather massive pedestrians and vehicles in very short time and very small space.The traffic flow generated by some special event could be over-saturated and dissymmetrically distributed in a road crossing due to its characteristic of huge peak flow and big dissymmetry coefficient,which puts forward a new request to the conventional control strategy and plan on road intersection.Some scholars proposed that each phase for an entrance can be used to solve the problem of dissymmetrical traffic flow caused by special event.However, the existing research can not differentiate the applicability of symmetry phase design and each phase for an entrance though the characteristic of the two have been analyzed.Regarding the arterial coordinated control,the present approach only includes symmetry phase arterial coordination and the coordinated control of each phase for an entrance.The mix phases arterial coordinated control is still expected to be solved.This paper first reviews domestic and foreign research on the traffic management and control of special events.Some macroscopic traffic management measures and microscopic traffic control strategy about special events are summarized.Then the author systematically introduces the present commonly used single intersection control policy and arterial coordinated control method,and analyzes their respective merits and drawbacks.Based on these,the research goal and research content of this dissertation is introduced.The second chapter mainly introduces the elementary theory of traffic signal control,including basic concepts,phase design,signal timing method as well as common types of traffic signal control.Each kind of control parameters and evaluating indicator,the basic principle of phase design,the phase primary election and phase adjustment and common phase plan as well as and equal saturation timing method are introduced in detail.The third and the fourth chapter are the key parts which focus on the choice of phase plan and arterial coordinated control method with signal road intersection under dissymmetry flow.In the third chapter,the author first makes a qualitative analysis on the merits and drawbacks of two kinds of phase plan to be choosed,then conducts a number of combination simulation experiments in VISSM to compare symmetry phase design with each phase for an entrance,and finally determines different phase strategy for different traffic supply and demand conditions.In the fourth chapter,symmetry phase arterial coordinated control method is first introduced,including the graphic method and the analytic method,and two examples are separately given to analyze the merits and drawbacks.Then the arterial coordination control method of each phase for an entrance is introduced,similarly there is an analysis to it with an example.Based on these,the author proposes a mix phases arterial coordinated control to road intersection,and the control strategy is discussed.At last,four intersections around the Xinhua Lu stadium in Wuhan are selected as the experimental subject.The author designs four kinds of testing plan,including symmetry phase single control,mix phases single control,symmetry phase coordinated control and mix phases coordinated control.A simulation road network is established in VISSIM and four simulation experiments are carried out.The results and analysis indicate that with the mix phases coordinated control plan,the four intersections of the artery obtain smaller average delay and the least stops, which confirms the superiority of mix phases arterial coordinated control strategy proposed in this dissertation.