Multi-Scenario Simulations And Evaluation On Time-Space Bus Transit Priority

Urban public transport has the advantage of intensity and environmental-protection, it is the necessary choice to relieve urban traffic congestion. Conducting bus priority has become a fundamental national strategy. Priority for right of way for public transport is the key focus. Now our nation lacks the effect evaluation for layout of bus lane, and we don’t take bus lane and signal control into consideration as a whole. So the effect of bus lane is not positive. This paper aims at researching the result of integrated priority right of bus in spatial dimensions and time dimensions.Firstly, this paper carries out traffic survey in Zhongshan road in Nanjing to obtain the data of spot speed and traffic in peak hour. And it gets the index of traffic composition、traffic volumes、 speed、delay and saturation by calculation. Through analyzing, this paper grasps the conditions of traffic operation under present situation.Then this paper introduces the advantages and disadvantages of outside bus lane and inside bus lane. Then three signal control methods are introduced including no signal priority control, traditional signal priority control and pre-signal priority control.6 scenarios are proposed in order to reflect integrated priority concept. This paper wants to find the best scenario through simulation.With VB and VISSIM_COM interface, the secondary development of signal-control module is made in microscopic simulation VISSIM to realize the 6 scenes above. To reflect the effect of priority to bus in a comprehensive way, evaluation indexes are given from the aspect of public traffic、private traffic and system. They are average delay of bus, average stop delay of bus, average stops of bus, average delay of private traffic, average stop delay of private traffic and average travel time of passengers.The result shows that providing priority for bus can promote the benefit of bus. After setting up bus lanes, the delay of bus and private car both reduce for non-interfering. In this case, the outside bus lane is better because of heavy left-turn traffic. After providing signal priority, the benefit of bus gains further. Under the conditions of outside and inside bus lanes, providing traditional signal priority makes the average delay of bus decreased by 4% and 2%, and providing pre-signal priority makes the average delay of bus decreased by 33% and 20%. The increment of delay of private car is controlled within 15%. Under the volume of traffic collected by traffic survey, providing outside bus lane with pre-signal priority performs best which makes the average travel time shortest and it is the best scenario.This evaluation method which proposed by this paper can direct the settings for bus lane and signal priority, and it has a good prospect in engineering practice.