Research On Degraded Road Network Traffic Flow Evolution With Information Guidance

From the point of view of the operation process of network traffic flow,traffic flow is often in an unbalanced state because of the interference of external or internal factors.It is very important for traffic management to study and master the dynamic evolution process of traffic flow from unbalance to balance.Studying the dynamic evolution will help to formulate more scientific and targeted traffic management measures.However,the current research on the evolution of network traffic flow is mostly confined to non-degraded road network,but the stochastic uncertainty of traffic supply and demand has become a new normal of urban traffic system in China.At the same time,advanced traveler information system(ATIS)is one of the important measures to alleviate various traffic problems.Based on this,in view of the degraded road network,this thesis studies the following aspects:Firstly,the thesis chooses uniform distribution to describe the random change of road capacity.On this basis,an updating model based on traditional route updating rules under degraded road network is constructed.The model is updated with the actual travel time of the previous day and the expected travel time of the previous day.The influence of parameters and capacity degradation coefficient on traffic flow evolution of degraded road network is analyzed by an example.Evolution results show that:1)under degraded road network and non-degraded road network,traffic network can evolve to stable state,but can't evolve to stochastic user equilibrium state;2)Compared with non-degraded road network,it takes longer for the degraded road network to evolve to stable state.Then,in order to accelerate the efficiency of traffic flow evolution under degraded road network,the thesis adjusts the updating rules of traveler path selection.In view of the degraded road network,the weighted moving average-based path updating model is constructed for both information and non-information environments.The model depicts the learning process of travel experience,takes into account multi-day historical travel data,and weighted moving average the historical travel time according to the importance of the current day travel decision-making.By comparing and discussing the influence of parameters on the evolution of traffic network under the two environments,the results of traffic flow evolution under the traditional route renewal model and the weighted moving average based route renewal model are compared and analyzed.The comparison results show that the updating rules based on weighted moving average are advanced.Finally,in order to investigate the influence of information guidance on the evolution of traffic flow in degraded road network,for degraded road network,travelers are divided into two categories:travelers with guidance information and travelers without guidance information.A mixed traffic network based on weighted moving average updating rule is constructed.Finally,a numerical example is used to analyze the influence of each parameter on the evolution law of traffic network when two types of users are mixed on the road network.Evolution results show that when the capacity degradation coefficient is greater than 0.3 and the traveler's dependence on the travel time of the perceived path is not less than 90%,no matter what the market penetration rate is,the traffic network can evolve to a stochastic user equilibrium state.At this time,the effect of the traffic network evolution is the best.