The Study Of Microscopic Traffic Simulation Technology In The Urban Road System

Traffic simulation is a technique to reproduce the dynamic process of traffic flow by using mathematical model. With development of extended Idea of transportation system management (TSM) and intelligence traffic system, traffic simulation technique is applied in transportation management, traffic control, transportation planning as well as the enhancement of transportation infrastructures extensively.Based on urban traffic network simulation system-UrbanSim that was developed on the platform of CORSIM, the paper does a research of the theory about application of simulation technology in urban transportation. Coordinated control of major road signals is a valid pathway to reduce vehicle queue delay and numbers of stop at intersections; traffic simulation model of coordinated control imitates vehicle performance in traffic network through mathematical model. We can study how to affect vehicle flow due to alteration of traffic network signal parameter. Through coordinated control of WuYi Road, a main artery in Changsha, we can calculate offsets by graphical analysis in the simulation software. On the base of completing coordinated control, the paper introduces the theory of actuated control which has been developed perfectly in western countries for many years and the application of UrbanSim in actuated control. Through experiments, the paper analyzes possibility and benefit of actuated control if it be put into use along WuYi Road. In theoretical study, through analyzing operational characteristics of traffic flow in roundabout and studying the acceptable gap influence on delay and different arrival distributions effect to the capacity, the paper brings forward the experiment methods to study the capacity of roundabout by using the simulation technology. At last, based on the feature integrating traffic simulation with traffic assignment, the paper compares the link volume by using different traffic assignment models, and analyzes the influence of user equilibrium and system's optimal assignments on travel time, travel speed as well as traffic volume on links. Further, the paper introduces the study on the influence of traffic composition on road link dynamics and the traffic simulation application in formulating dynamic traffic assignment models.