Distributed Traffic Control System Based On Network Congestion Control And Its Computer Simulation

Along with the social and economic development, people's demand on frequent going out has increased rapidly. However, the facility construction of the urban transportation has fallen far of the vehicle increase and there has no obvious change of the transportation capability. As a result, urban traffic congestion has become a great problem facing big cities all over the world. Take the US as an example, from 1976 until now, its vehicle kilometers rise by 77% every year, but its road kilometers grow only by 2% at the same time. During the rush hours, 54% of the vehicles are in traffic congestion. Because of this, it takes 1.5 hours more than usual to commute and the cost of commercial transportation is greatly increased.At present, the most effective way of solving the urban traffic congestion is intelligent transportation system (ITS). ITS is an applied area which is highly concerned and rapidly developed recent years in the world. It means to integrate advanced computer technology, communication technology, electronic control technology, artificial intelligent technology and geographic information technology and effectively apply the integration to traffic management system. By comprehensively considering such factors as man, vehical and road, it aims at establishing a wide-range, omni-direction, accurate, real-time, and effective traffic management system.Urban transportation is the most important part of the entire transportation system and building signal control system is the chief task in implementing intelligent transportation system. One of the applied work in ITS research is to explore the best approach to control urban transportation.This thesis applies the principle of TCP network congestion control to the control of urban traffic congestion and studies distributive traffic control algorithm based on congestion control. By analyzing and comparing the characteristics of traffic network and computer data communication network and the congestion reasons, the thesis summarizes their common features and puts forward a distributive control approach to solving urban traffic congestion. The approach is applying data-packet grouping transmition in data communication network into vehical grouping management at road intersection. The principles of proximity and aversion are also used in improving the algorithm. In addition, the thesis states the algorithm of distributive traffic congestion control, and designs a program to conduct simulation test of the system.The time used in controlling the vehicles by the algorithm is three, two and two cycles shorter respectively than the reported algorithm. The test shows that the system is superior to traditional fixed-time control and induction control and is capable of better solving urban traffic congestion.