Micro-Simulation Of Roundabouts Based On Vissim

Roundabouts is a special form of the intersection. By setting the central island in the center of roundabouts, the vehicle can be ordered into a continuous intersection and traveling counter-clockwise around the island. The Roundabouts not only has less conflict points which makes them much safer but also can beautify the city.With the increasing urban traffic, roundabouts have become the congestion bottleneck of urban network. In order to solve this problem, setting stop-line and traffic lights, changing the roundabouts into Intersection with signal or Grade separation are the two main methods that currently used. The former one has limited effect while the latter has massive costs of construction and maintenance and a potential impact of cities’ appearance. Therefore, the Micro-simulation of Roundabouts is particularly important. In order to establish the micro-simulation model in line with the actual running state, this thesis use VISSIM to simulate the roundabouts. The main contents are as follows:(1) This thesis introduces the characteristics of roundabouts, analyzes the behavior of the vehicle running in different regions of the roundabout, and summarizes our roundabouts vehicle running characteristics.(2) This thesis introduces a method to establish simulation models roundabout by VISSIM, analyzes the specific network modeling process, including survey data, road network establishment and road network testing. In addition, it points out the issues that should pay attention to in order to improve the accuracy of the modeling.(3)Using correlation analysis, this thesis selects the parameters about significantly affecting roundabout’s running state. Furthermore, it writes genetic algorithm programs by Visual C++programming language, and achieves Visual C++’s call to VISSIM by VISSIM’s COM interface. Finally, this thesis establishes a roundabout parameter correction system by a framework based on MFC.(4)This thesis selects a roundabout located on Shulong turntable in Xindu. By the method of modeling and parameter calibration system designed in this thesis, actual intersection of simulation and modeling parameters were corrected. This thesis calculates the capacity of the roundabout by using the corrected model, and finally, it verifes the reasonableness of calculated results.