The Mechanism Of Traffic Flow Characteristics Under Adverse Weather Conditions

Traffic accidents have become an important reason of the Chinese damage, and the rate of traffic accidents under adverse weather is much higher than the normal weather. How by studying the mechanism of traffic flow under adverse weather condition, to accurately grasp the traffic flow characteristics of adverse weather, to effectively manage and control the traffic flow of adverse weather, it is great significant for solving traffic problems under adverse weather.Based on the national natural science foundation, the mechanism of traffic flow running characteristics of adverse weather is studied, including the analysis of rain traffic flow characteristics, the calibration parameters of following model, the lane change model and simulation analysis of adverse weather.Firstly, the adverse weather is classified and graded according to the meteorological standards, based on rainfall classification criteria the traffic flow data is selected under four different grades of rainfall, and its flow?speed characteristics, and the relationship between the characteristics are analyzed and compared with normal traffic flow characteristics.Secondly, the relationships between rainfall and the water film thickness, water film thickness and surface friction coefficient are analyzed, with the maximum braking acceleration and safe distance as an intermediate variable, the desired vehicle speed is got by converting time occupying ratio and density parameters, according to the safe distance model and the desired speed model, the full-speed model considering rains is established, and the parameters are calibrated with the actual traffic flow data, and then the calibration results are evaluated.Finally, the indicators of the road adhesion coefficient and the driver's reaction time of adverse weather are quantified, and then the lane change model considering the impact of adverse weather is established, and through simulation the lane change rate and space-time diagram of sunny, rain, fog, snow day are analyzed, all these results can reflect the lane change mechanism under adverse weather effectively.