Research On Control Strategy Of Roundabout Based On Bus Priority

With the continuous increase of the number of motor vehicles in China's cities,traffic congestion has become an important reason for restricting urban development.The road resources of public transportation are low in occupancy,with a large number of passengers and high transportation efficiency.Therefore,giving priority to the development of public transport can effectively alleviate urban traffic pressure,improve traffic efficiency,improve the current situation of traffic congestion,and promote the healthy development of urban traffic.At present,more and more roundabouts in China choose to change the signalless control to signal control,or to reconstruct the circular intersection as a crossroad,but because the cost is too high and it is not conducive to the protection of surrounding vegetation,The scheme of the person is inferior to the scheme of the former.However,changing the island with no signal control to the island with signal control can not solve the congestion of all roundabouts.In combination with China's current policy of promoting environmental protection and reducing vehicle emissions,it is actively promoting the rapid development of public transportation.An important choice,using bus priority and other strategies will give full play to the applicability and economy of public transportation,and help the citizens to travel convenient,which is also an effective way to quickly improve the efficiency of urban traffic.Due to the slow development of public transportation,the proportion of people who choose to travel by bus in cities is difficult to achieve the expected proportion of travel.As more and more cities are building subways,public transportation has a lower proportion in daily travel modes.Although most cities in China have built bus lanes to ensure the independent road rights of public transport vehicles,considering that public transport vehicles share the same traffic signals as social vehicles,the traffic efficiency of public transport vehicles cannot be guaranteed.For the circular intersection in this paper,in order to improve its traffic capacity,signal control can be implemented on the roundabout,and at the same time,to promote the development of public transportation,the bus traffic delay can be effectively reduced without seriously affecting the traffic efficiency of social vehicles at the intersection.Targeted improvement measures for public transportation.Optimize the circular crossover with the goal of minimum per capita delay,set the priority of public transportation as the precondition,quantitatively analyze the delay of the imported lane and the length of the queue,establish the bus lane,establish the corresponding minimum per capita delay model,and match the signal of the roundabout.The optimization is carried out,and the Vissim simulation software is used to simulate the traffic capacity of the roundabout,and the signal control and safety assessment are simulated and analyzed to improve the traffic capacity of the intersection and reduce the delay.This paper mainly carried out the following research:Firstly,the traffic characteristics of the roundabout are analyzed.The conflict points that may occur at the roundabouts under different control are analyzed.Three measures to improve the capacity of the roundabout are analyzed.The signal of the roundabout is introduced.Single and dual signal control methods in control mode.Secondly,the research on the real-time bus priority control problem at the intersection of the city was carried out,and the bus priority was summarized.The goal of bus optimization at the roundabout is proposed with the minimum per capita delay.The signal cycle duration and green time are taken as the optimal decision variables,and the real-time bus priority control model is constrained by the intrinsic relationship between cycle duration and green time.Thirdly,through the micro-simulation VIS SIM software,the simulation and evaluation of the round-trip intersection control scheme based on bus priority is carried out.The simulation shows that the bus priority transformation scheme proposed for the signal control at the roundabout has good control effect and improves the bus.The service level and pass rate also improve the service level of the roundabout.