Analysis Of Road Traffic Flow Situation Characteristics And Research On Speed Guidance Strategy

The traffic flow on the road is very susceptible to traffic disturbances.As the disturbance spreads along the fleet,the flow of traffic will fluctuate.Traffic flow fluctuations are the external appearance of acceleration fluctuations.The study of the internal factors of traffic flow fluctuations and the macroscopic characteristics of traffic flow is essential to the stable operation of traffic flow.The system analyzes the dynamic characteristics of traffic fluctuations,and then analyzes the macroscopic characteristics of traffic flow,optimizes the design of vehicle speed guidance strategies,and provides technical support for improving the overall stability of traffic flow and reducing the impact of traffic oscillation disturbance on traffic flow.Firstly,sort out and analyze various traditional car-following models,and study molecular car-following models based on molecular dynamics.Introduced the ACC model and its improvement in the intelligent networked traffic scene,reasoned and analyzed the dynamic characteristics of the mixed traffic flow in the networked environment,and established the dynamic model of the traffic flow characteristics.Secondly,in view of the phenomenon that the running speed and acceleration of car-following vehicles show random dynamic fluctuations,the relationship between basic parameters of traffic flow is used to determine the quantitative relationship between the required safe distance and speed between vehicles;Define the acceleration fluctuation sensitivity coefficient based on the molecular car-following model,and use the measured data for parameter calibration and numerical fitting to determine its quantitative relationship;Focusing on acceleration changes,the internal factor of traffic fluctuations,systematically analyze the relationship between acceleration fluctuations and the evolution of traffic flow situation,and explore the evolutionary laws of traffic flow in free,synchronized and blocked states.Then,on the basis of the acceleration fluctuation analysis,the expressway traffic flow situation division method is designed based on the k-means clustering algorithm,and the numerical simulation verification is carried out based on the traffic flow data obtained by the video detector of Qingdao Huanwan Expressway;Based on the wave speed theory of traffic flow situation characteristics,a traffic flow situation index model is constructed,and then the evolution law of traffic flow situation is analyzed.The traffic flow situation index and the acceleration fluctuation sensitivity coefficient are compared and analyzed,and compare the fitting results of the vehicle flow situation index model with the results of situation division using k-means clustering algorithm to verify the validity of the model.Finally,design a connected vehicle speed guidance strategy for mixed traffic flow in a connected environment.Predict the downstream HV disturbance trajectory,and then optimize the upstream CAV operating speed.Guide the the fleet where the upstream CAV is located to achieve the goal of smoothly merging into the downstream traffic flow at a reasonable speed.The simulation experiment shows that the higher the CAV ratio,the farther the disturbance start position,the more obvious the degree of restraining traffic oscillation,the higher the stability of traffic flow.It can reduce the risk of collision between vehicles,improve driver comfort and overall traffic efficiency.