Study On Speed Limit Technology Of Freeway Tunnel Group In Mountainous Area

With the continuous increase of mountain freeway mileage,the number of tunnel group is increasing year by year.Due to the complexity of the driving environment,the tunnel road is always a traffic accident prone road.How to reduce the traffic accident rate and reduce the severity of the accident is one of the important problems in the traffic safety of mountainous highway.Among the many factors that lead to traffic accidents in tunnel group,one of the most important reasons is that the speed and the special environment of tunnel group are not harmonious.Therefore,it is necessary to study the accident characteristics and speed limits of the tunnel group,which can provide theoretical support and technical support to improve the traffic safety of freeway tunnel group.Firstly,this paper summarizes and analyzes the factors that affect the speed limit of tunnel group.On the basis of a large number of domestic and foreign research results,this paper gives the definition of tunnel group based driver's visual characteristics.Then,the paper analyzes the common concept of velocity in engineering,and makes clear the difference between limiting speed and other speed.Then,from the point of view of human,vehicle,road and environment,this paper makes a qualitative analysis of the factors that affect the speed limit of the tunnel group,which provides a theoretical basis for the study of speed limit technology.Secondly,the speed limit technology of tunnel group is studied.Based on the accident data and velocity data of tunnel group,this paper analyzes the speed limit section of tunnel group,and puts forward the constraint strip which should be taken into account when setting the speed limit standard of tunnel group.Based on these constraints,the calculation model of tunnel group speed limit value is constructed.According to the characteristics of variable speed limit,this paper puts forward the method of variable speed limit in the congestion condition of tunnel group,and constructs the variable speed limit model.According to the accident characteristics and speed characteristics of tunnel group,the speed limit facilities of tunnel group are studied.Finally,the paper applies the speed limit technology of tunnel group and makes a simulation evaluation of the speed limit effect.The speed limit value of LUO LUAN freeway tunnel group is determined by the speed limit technology,and the VISSIM simulation software is used to simulate the variable speed limit effect of tunnel group in the congestion condition.Then,the speed limit effect of LUO LUAN freeway tunnel group is evaluated.The simulation results show that the variable speed control method can effectively reduce the congestion degree of tunnel group section under accident conditions,is conducive to maintaining the stability of traffic flow in tunnel group under Congestion,can improve the effect of tunnel group traffic safety.Using the method proposed in this paper to set the speed limit of tunnel group section,not only can guarantee the road traffic efficiency,but also can improve the safety of the tunnel group section.