The Study Of Dynamic Route Chioce Model Based On VMS Information Environment

As an efficient way of transport demand management, Intelligent Transport System (ITS) has been established and put into use in some big cities in China; and noticeably, the Advanced Traveler Information System (ATIS) can provide travelers with real-time and accurate traffic information and path leading, thus influencing their travel habits. Being an important part of ATIS and a kind of widely used Advanced Traffic Management System (ATMS), VMS, which acts as an outdoor media delivering real-time information all around the clock, has been favored by lots of cities for its irreplaceable advantages in addressing the traffic problem caused by the increase of motor vehicles. Hence, it is of great theoretical and practical significance to conduct research on the dynamic models of choosing travel path under the VMS information environment.Firstly, this paper discusses the behaviors and patterns of choosing travel path under the common information environment; and on this basis with the fundamental functions and information characteristics being concerned, this paper further expounds on the behaviors of choosing travel path under VMS information environment; and in accordance with the theory of dynamic programming, the process of choosing travel path is described as a multi-stage decision-making process which applies road-net nodes as decision points. This process is the theoretical basis of dynamic route choice model.Secondly, with regard to the elements influencing traveler’s path choosing under the VMS information environment, the paper conducts questionnaire survey and data analysis. With the statistical analysis on the survey data, this paper defines these elements, including driving years, the specific basis for choosing path, the length of time for the endurance of delay, and timeliness of VMS delivering. Through numerical simulation of random process about traveler route choice and the result of the random probability statistics, the proportion of traveler changes his path under the VMS information environment is finally turned out to be50.36%. This value is an important parameter of the traveler dynamic route choice model mentioned in the later part of this paper.Lastly, combined with the analysis of the SP investigation, the route choice model under the VMS information environment is established on the basis of existing dynamic route choice model. The stochastic dynamic user optimal control model is established to be proved that the optimal solution is a SDUO condition, and the concrete solution procedure is elaborated. Moreover, a small-sized road-net designed with three different scenarios is picked as example used for completing dynamic allocation in different scenarios by using the stochastic dynamic user optimal control model. The analysis result shows that VMS can efficiently lead the traffic flow; VMS can lead to the timely traffic volume transfer in the upstream section of the traffic flow through delivering information, thus enhancing the operational efficiency of the displayed road section; The leading effect would be better with the forecast information delivered by VMS. Research results of this paper would be a certain guiding significance to the construction and release strategy of VMS.