Simulation Study Of Urban Public Transportation System Based On Flexsim

With the rapid development of social economy and urbanization, the number of vehicle has increased dramatically and the traffic demand is rising simultaneously, which leads to some increasingly serious problems such as traffic congestion. As the citizens’main way to travel, public transportation system doesn’t get full play because of the limitation of itself and the traffic condition. Therefore, optimization of the public transportation system performance becomes an inevitable requirement of city development and life quality improvement. In traditional mathematical methods, traffic flow is studied based on fluid analysis. However, the traffic flow is discontinuous but the fluid is continuous. Therefore, mathematical model in describing the microscopic details of the public transportation system has certain limitations. As an important research method, discrete virtual reality simulation technology can effectively avoid the defect.In this context, this thesis applies the simulation system with planning and dynamic scheduling methods to effectively improve the operating efficiency of the public transportation system. The main contents include:First of all, a bus dispatching simulation system for one bus route and a transit simulation system with transferring among the multiple bus lines are established with the object-oriented discrete virtual simulation technology based on Flexsim. The functions of simulation system includes setting up the transit parameters, transit data statistics, simulating disturbance, control strategy validation and virtual 3D dynamic presentation of the running process. After implementing the basic function of departing by the schedule, driving across the bus line, dock and picking up the passengers, a graphical user interface is established for users interacting with information of the simulation model, which makes the disturbance simulation and the implementation of the scheduling policy is artificially applied to the simulation system. With the help of real 3D display effect, users can observe the temporary entities on the move, the system status and the operation situation in flight mode.Moreover, by considering that the passengers may choose the other way to travel when the waiting time is beyond their patience, bus departure interval programming model is established and solved with the enumeration. The bus departure interval is regarded as decision variable, and the bus loading factors are regarded as constraint, ensuring the passengers’waiting time not too long. The objective of this model is to maximize the daily operation gain of the bus company while the passengers’ waiting time is as short as possible.Finally, according to the planning and dynamic scheduling, experiments are performed respectively in order to figure out the relation between the departure interval and passengers’ waiting time, between the departure interval fluctuation and the headway regularity on bus routes, between the waiting time of passengers and the strategy of bus holding. Under the scenario under different parameters configuration, the influence of controllable parameters on the public transportation service performance and economic benefit are analyzed, and the feasible scheme is put forward to improve the public transportation system performance.The simulation system is set up as the experiment platform for a variety of traffic simulation experiments, which can get the results quickly and safely. The simulation system provides a reliable experimental foundation for managers to make right decisions. The simulation system can help managers to achieve the rational use of buses, optimize the allocation of resources and effectively coordinate the relationship between the passenger demand and bus resources supply. Ultimately, the simulation system can improve the operation efficiency of urban public transportation system, and provide good service for passengers.