Research On Traffic State Identification Method Of Urban Expressway Supporting Road Based On Thermodynamics Entroy

Urban expressway supporting road plays more and more important role in urban street networks system. In our country,general urban panning year is not very long,the increase of vihicles are growing so faster than the development of road that the phenomena such as traffic congestion emerge.So,under a low level of density of urban road network, reasonable application of supporting road can not only relieve traffic pressure of the main road,but also improve the service quality of supporting road.This paper discussed the similarity between road traffic system and thermodynamic system in order to analyze the supporting road traffic.Here,we applied basic theories of thermodynamics of nonequilibrium state to traffic flow field. Because traffic flow meet the three important features of fluid mechanics,which contained continuity, compressibility and viscosity. comparison of the two main parameters showed that traffic system has the property of fluid mechanicsandThe the theory of fluid mechanics can be used to describe the traffic flow.So,the continuity of the supporting road traffic system was set up based on the continuity equations of fluid mechanics by applying the priciple of momentum theorem, the continuity equations of fluid mechanics.The entroy production model was set up based on theory of thermodynamics and fluid mechanics by determining generalized force and generalized flow.by ananlysis we determined that negative entropy can be produced in designated state,so as to come into meaning of negative entropy. On this base,the total entroy model was set up,so as to come into traffic state identification entropy model.the determing of the threshold value of identification entropy digitized traffic identification and provide critical identification entropy value,so as cone into which provided quantitative data for the traffic control to access the best time to take control.In this paper, we take hexing road in harbin as research subject and the import and export of two different types of roads as the section of the survey.the traffic state was identified by taffic system identification entropy model after collecting traffic flow data in morning and evening peak hour. Linearity regression analysis on entroy value and journey time was made by spass software based on collected data.The result showed that traffic entroy identification method had a certain degree of fitting with traffic state standard selected.So,it can be applied widely.additionally,Several factors influenting the journay time on expressway supporting road were emulated by transmodeler VISSIM.Some advice on roade design and cotrol were given by analyzing the simulation result.