The Analysis Of The Road Network Under The Distribution Of Variable Message Sign

ABSTRACT:Variable message sign is the main tool of traveler information system in the intelligent transportation system, so it’s widely used in urban traffic management. VMS can provide relevant traffic information to drivers, which is an effective approach to achieve an equilibrium traffic assignment.As the functions of VMS and the traffic management measures based on VMS continuously improves, many big cities in our country such as Beijing, Shanghai etc. start to focus on application research and promotion of the VMS, which make the VMS network come into being. At present, acquiring the rules of the road state under the information distribution of VMS, which is one of the basic problems related to the control of that network, is order to enable every VMS to refer to the near road states when distributing information. It not only can enhance the ability of intelligent transportation systems, but also improve the efficiency of traffic management. Besides, it’s the directly needs of building a harmonious transport system..Firstly, this paper clarified the background of the distribution of VMS information. Secondly, it analyzes the relationship between the road states under the VMS information, which is the main part of the thesis. Secondly, on the basis of the mutual impact of road states. Finally, we take actual example for application.Concretely, on the foundation of the traffic information affecting the traveler, the road states could be stochastic under the information distribution. The hidden Markov model is selected to analyze the random distribution of road states. Combined with the basic definition of information in the sphere, we gave the transmission of VMS information and its attenuation in the road network; and on the basis of that, this paper analyze how to decide the location of the downstream VMS and gave the information distribution strategies. Finally, taking some roads for example, which are between the North Second Ring Road and Third Ring Road in Beijing, this paper analyze the impact of VMS information actually.