Optimal Control Model Of Multiple Bus Signal Priority Requests For Isolated Intersection Based On Headway

With the development of the economy,private car quantity in the city has increased rapidly,which cause serious problem of urban congestion.As the most effective way to solve such congestion,public transportation has developed rapidly in recent years,especially the bus.In order to improve the attraction of buses and reduce the travel of car,China mainly adopts the bus priority strategy to reduce the delay of bus lines and improve the service level.However,China's buses have the characteristics of high frequency,high number and large traffic volume,which easily cause multiple buses request priority at the intersection at the same time.To solving such problem,they usually use priority strategies based on delay minimum and first come first come first served basis.These methods can reduce the delay of the bus at the intersection in some extent,but the unconditional priority given to the bus is likely to lead to headway's non-uniformity distribution,bus bunching and decrease of the accuracy.Thus lead to a reduction of service level and attractiveness of buses,this thesis takes the running time of buses at intersections as the research object,and proposes a bus priority control model based on the headway.The main contents are as follows:(1)The domestic and international research status of bus signal priority is introduced,and the control methods such as passive priority,active priority and real-time priority of bus signal priority are compared.The characteristics of the headway are expounded,and the information of the bus station platform of Furong Avenue and the headway of the 105 bus line in Changsha City are investigated and summarized.(2)A single-line bus priority control method based on the headway is proposed.According to the deviation of the headway between buses on same bus line,the priority of the bus is judged.By controlling the bus's station time and the bus priority plan of the signalized intersection,the headway of the entire line optimized.The buses distribution is more balanced,and the punctuality rate of the line increases.(3)As the optimization control model for single-line bus can't solve the problem that multiple buses request priority at the same intersection,a multi-bus request conflict priority control model based on the headway is proposed according to the time when the bus arrives at the intersection stop line,the departure time of the headway,the expected headway and other parameters.And the optimal signal control scheme is calculated based on the sliding time window method to minimize the overall headway and the deviation of expected headway of the bus passing through the intersection.(4)This thesis use four optimization targets to compare the result of the example and find multi-transit model based on headway not only can give the bus priority according to the bus's headway,but also can improve overall headway of all buses at the intersection.