Modeling And Implementation Of Transit Signal Priority Control For Multi-conflicted Routes Under Signalized Intersections

It’s necessary to actively implement transit signal priority technologies when developing urban public transportation. Generally, transit signal priority (TSP) control can use advanced technologies to give extra green time to buses in order to maximize bus efficiency and provide more benefits to bus passengers, such as traffic detection, automatic control and computer science technologies. Moreover, the TSP control can also improve public transit trip contribution rate, attract more passengers to take bus, as to restrain the increasing of passenger cars, and relieve urban traffic congestion. Under limited road and traffic resource situation, TSP, one of the most efficient traffic control methods, could improve regularity and punctuality of public transit services.This paper studies show to grant the TSP control with multi-priority requests from different bus routes at the isolated signalized intersection. The proposed method will consider the benefit of bus passengers and passenger-car users at the signalized intersection. First, this study estimates bus passenger waiting time at the next bus stop, and then calculates the total person delay of entire intersection. The objective function is to minimize the bus passenger waiting time without increasing the total person delay at the entire intersection. Finally, a platform of traffic simulation based on VISSIM, an unbiased micro simulation tool, is employed to evaluate the performance of the developed model. This paper mainly focuses on these aspects:(1) The existing TSP control methods are reviewed in the Section2, such as passive priority and active priority. And then compare these two methods, select active priority control as my control strategy. Moreover, aiming to limitation of simulation technologies, this paper presents a platform of traffic simulation for large-scale road network.(2) Under headway-based bus operations, when buses of different routes apply for priority simultaneously, bus passenger average waiting time before and after bus priority control has been estimated. Then, bus delay and passenger-car delay has been calculated. Finally, based on the proposed objective functions, the proposed TSP control will minimizing bus passenger waiting time at the next stop without increasing total delay of entire intersection. (3) According to the established Mathematical model to the multi-priority request, a TSP control logic and implementation process is developed. And the developed TSP control algorithm is programmed to validate it based on VB.Net, MYSQL and VISSIM.COM interface. Then the reasonability and feasibility of developed TSP model is embodied in the actual road network and comparison with classical TSP.(4) Based on shortcomings of current simulation software, this paper establishes public transit simulation platform to design road network, input public transit demand, design signal control method, and analyze the performance of the proposed program. The developed platform of public transit can integrate proposed TSP control method which could provide decision making support on bus network design, public transit operation and management as well as transit priority control design for planners and engineers.The proposed TSP control is used to handle with multi-priority requests under headway-based bus operations with giving variable priority time for bus vehicles in order to improve regularity of bus vehicles at the next bus stop. Compared to the "first-come and first-served" strategy, the developed TSP could effectively improve the regularity of buses, and reduce the average bus passenger waiting time, as well as passengers’ delays and road network delay. Considering the relationship between traffic flow and bus ratio, sensitivity analysis showed that when the bus ratio is about equal to3%, the TSP control can significantly reduce the bus passengers’ delays and total network delay.