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Research On Coordinated Control Theory Of Transit Signal Priority

Posted on:2010-01-23Degree:DoctorType:Dissertation
Country:ChinaCandidate:F LiFull Text:PDF
GTID:1102360272996185Subject:Traffic Information Engineering & Control
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"Developping public transportation"has become a consensus to modern solve urban traffic problems. Signal control method can reduce delay of bus at the intersection and travel time to provide convenience to residents. Transit signal priority is an important technology to achieve "public priority" strategy. Thesis studies the suitable signal timing method for transit signal priority to reduce bus delay and improve bus level of service. The research findings of the dissertation contribute to a further study into the urban traffic control system, which maintains high value and guidance function in scientific research.The object of this thesis is public transportation of network and the control target is to reduce bus delays as little as possible and maintain general traffic stably running. It explore transit signal priority control algorithms of a single-vehicle bus, single bus flow , two and more bus flow with active and passive transit signal priority control method to meet different transit traffic demand. This dissertation consists of the following chapters interrelated with each other:(1) Design the framework of transit signal priority control: according to the objectives, principles and functions of the transit signal priority control, the strategies of transit signal priority control is established. It brings forward the system of transit signal priority algorithm and designs layout of the hardware devices and data flow matched to signal priority control algorithm.(2) Propose active transit signal priority control method at a single intersection: after analyzing coordinated control impact on transit signal priority, the circumstance where early green and green extension strategy applied in the transit signal priority control is provided. Based on meaning and idea of Ring, green extension maximum which is affected by green time of bridge phase in the ring is established, and the whole control logic of active transit signal priority control, early green strategy and green extension strategy are built with non-public phase green optimization model under transit signal priority control. According to logic of active transit signal priority analysis, transit signal priority manages the analysis with the multi-loop and pedestrian phase and study early green strategy and green extension strategy impact on traffic control effect. Analysis shows the result that is early green strategy can reduce vehicle delay when the other phases are not congested, and the circumstance of green extension strategy by flow rate is less than early green strategy.(3) Propose passive transit signal priority control method at a single intersection: from the view of optimization goal cycle optimized by average delay of vehicles is the same as average delay of persion in transit signal priority control; extra green time model of intersection is provided with spilt determined method impact on traffic control effect, and the phase sequence optimization method which is insert bus phase at unsatured green of general traffic green and signal timing parameter model is established according to analysis that the capacity of the phase together with left traffic and straight traffic will increase. The simulation results demonstrates active transit signal priority control not relied on bus information, but on general traffic flow not only can reduce the bus delay, but also improve green utilization and ensure the green level of service of intersection.(4) Study active transit priority coordinated control algorithm: The layout of bus detecter under active transit priority coordinated control and bus travel time predicted model used in signal time optimization is first step of active transit priority coordinated control algorithm. Secondly cycle optimization model established by making the deviation between actual distance and ideal instance smallest uses Simplex Method (SM) to solve the opimazation. Singal time optimization model propose the main control objectives is green wave of general traffic and the subsidiary objective is green wave of bus traffic under different decision-making and builds comprehensive benefits optimal control model to determine the optimum decision-making with green wave band, general traffic average delay and transit traffic average delays so to achieve active transit priority signal coordinated control. Finally, with VISSIM to verify, the algorithm shows the result that active transit priority coordinated control can make delay of transit traffic minimum ensuring the other phase not congested.(5) Study passive transit priority coordinated control algorithm: In order to ensure reliability of general traffic and bus traffic, layout methods on detectors of general traffic and bus traffic traffic, and the method of traffic flow are determined; based on association on upstream and downstream of network, as well as coordination attributes of traffic flow, network relevant parameters of transit signal priority control are described. According to relation between time when upstream arrvive at downstream and green time of downstream, time band models of exterior flow and interior flow are developed to determine signal timing parameters effect on flow running through intersections. Average delay model based on time band model of traffic flow is established by area computing method to get the delay of bus average delay and vehicle average delay. So optimization goal for making average person delay smallest is provided to realize the network signal timing optimizationThe major innovations of the thesis are:(1) Active transit signal priority control algorithm develops signal timing method of transit signal priority considering the effect of different green and pedestrian phase to guarantee the realization of transit signal priority at complex conditions when offset and cycle remaining the same.(2) Passive transit signal priority control algorithm proposes signal timing method of transit signal priority which is insert bus phase at unsatured green of general traffic green to achieve transit signal priority without real time bus detected information.(3) active transit priority coordinated control algorithmpropose the main control objectives is green wave of general traffic and the subsidiary objective is green wave of bus traffic under different decision-making to achieve singal bus traffic flow signal piroirty with reasonable vehicle green band to effectively integrate the transit traffic coordination and general traffic coordination control .(4) average delay model based on time band analyzes the six condition of relations between time when upstream arrvive at downstream and green time of downstream, and establishes time band model and vehicle delay model to solve the problem that assumption arrive pattern of traffic flow is uniform is not the true,so as to make the delay model more reliable and approach the reality...
Keywords/Search Tags:traffic control, active signal priority, passive signal priority, cooperated control, optimization index
PDF Full Text Request
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