Traffic Situation Prediction And Intelligent Control Technology Of Expressway Under Ice And Snow Pavement Conditions

Transport is a basic,pioneering and service industry in National Economic and social development,and plays an important role in promoting and supporting national economic and Social Development.Compared with common highways,expressway has great political and economic significance in promoting the development of social transportation because of its large traffic flow and strong transport capacity.The ice and snow weather has caused the serious influence to our country north broad area highway.China has a vast territory,and winter ice and snow weather conditions are complex,on the highway capacity and safety will cause serious impact.The ice and snow weather will cause the road surface adhesion coefficient to drop,the vehicle brake distance increases greatly,causes the serious security hidden danger.At the same time,the lateral stability of the vehicle tire is significantly reduced,which makes the vehicle more prone to sideslip when driving in a curve.In addition,ice and snow weather will also cause a significant decline in road visibility,which will have a negative impact on drivers' psychology,increase the burden of driving and the probability of misjudgment,resulting in driving risks.Based on the characteristics of the expressway in Jilin Province,this project puts forward a method to predict the impact of ice and snow on the road surface environment,focusing on the important nodes such as long downhill and continuous curve,on the basis of which,based on the traffic investigation and simulation analysis,a pre-evaluation method of Expressway Traffic Operation State in ice-snow environment is proposed to predict the evolution trend of expressway traffic operation state under ice-snow condition,the intelligent management and Control Technology of expressway under ice and snow condition is put forward,in order to guarantee the safety and efficiency of expressway traffic operation under ice and snow conditions,the methods of dynamic current limiting,variable speed limiting,lane management and traffic flow guidance are adopted.Under the condition of ice and snow,expressway current limit can be divided into two kinds of current limit strategies: main line current limit and ramp current limit.The main line current limiting is to limit the frequency of vehicles entering through the toll booth of the current limiting section,and dynamically control the traffic density of the current limiting section of the expressway according to the degree of influence of the ice and snow conditions on the road,in order to achieve the vehicle safe passage and as far as possible to improve the efficiency of road traffic purposes.On-ramp restriction is a measure to dynamically allow or prohibit vehicles to enter on-ramp in a certain period of time by means of signal control according to the traffic flow state and road surface state of the area in front of the on-ramp,its main objective is to reduce the risk of merging into traffic flow while helping to control the traffic density of the restricted section.As a new method,variable speed limit is more and more widely used in highway traffic control.At present,the research on variable speed limit mainly focuses on the optimization of expressway bottleneck area,and lacks the research on variable speed limit control of expressway under ice and snow weather.The control method of the invention takes into account the influence degree of ice and snow weather on the road surface,and adopts the method of variable speed limit to carry out traffic control,so as to improve the traffic efficiency and safety of the expressway under ice and snow conditions.It provides scientific basis for expressway traffic emergency management,helps to minimize the adverse effects of ice and snow weather on traffic,and realizes the scientific management of expressway traffic operation under ice and snow conditions.