Research On Echo Characteristics Of Expressway Traffic Flow

The goal of the traffic flow theory is to reasonably construct the relevant traffic flow model which can describe the unique characteristics of road traffic,and to reveal the important laws of the complex dynamic characteristics of traffic flow under different phases in the adjustment and control road,It provides a strong guarantee for the sustainable development of society in terms of preventing and alleviating traffic jams and effectively guiding the practice of traffic engineering.In recent years,traffic congestion and other serious phenomena have gradually become the key problems to be solved in the current society.The occurrence of traffic congestion has brought adverse effects on the excessive consumption of energy,environmental noise pollution,deterioration of climate conditions,and has gradually become the restricting factors of China’s social and economic development,ecological environment protection,people’s health and happiness.Accelerating the research and analysis of the development of traffic flow related theory has important engineering application value and far-reaching scientific theoretical significance for improving the service level of Expressway and solving the problem of traffic congestion.In order to further explore the micro impact of the speed disturbance between the target vehicles on the traffic flow,based on the three-phase traffic flow theory as the main line,this paper proposes an improved cellular automata model on the basis of the original classic kkw model through detailed division of driver behavior tendency factors.At the same time,the MATLAB software is used to simulate the statistical analysis of the new improved model to explore the fluctuation of speed disturbance between the target vehicles in different traffic flow phases and the propagation trend of echo with acceleration and deceleration effect.The main contents of this paper are as follows.(1)Compared with the traditional traffic flow theory and three-phase traffic flow theory,the explanation of the speed fluctuation between the target vehicles in the expressway and the congestion caused by the characteristic echo with acceleration and deceleration effect is explained,and the advantage of the three-phase traffic flow theory applied to the traffic flow with complex,dynamic and random characteristics is established.(2)In this paper,considering the driver’s driving behavior characteristics,an improved cellular automata model based on the three-phase traffic flow theory is constructed,and the simulation data are statistically analyzed.It is found that the speed disturbance between the target vehicles and the echo with acceleration and deceleration effect characteristics have different evolution characteristics under different traffic flow phases.When the traffic flow is in the phase state of free flow,the duration of velocity disturbance and echo on a single target vehicle is short;When the traffic flow is in the phase state of synchronous flow,the change of velocity disturbance and echo phenomenon in the traffic flow will be rapidly transmitted along the upstream of the traffic flow,and the number of target vehicles affected is large,and the above characteristic phenomenon is difficult to dissipate.(3)Based on the driver behavior characteristics,when the traffic flow in the road is in free flow phase,the excessive acceleration and deceleration response of the target vehicle(aggressive driving behavior characteristics)will amplify the speed change disturbance and echo transfer phenomenon between traffic flows;The target vehicle(conservative driving behavior)will weaken the effect of speed change disturbance and echo transfer between vehicle flows due to its low driving speed and long physical distance.