Study On Traffic Accident Of Highway In Rain Weather Based On CAM

Freeway is the backbone artery of transportation network,which play an increasingly important role on social economy at present.Meanwhile,the traffic safety problem is also very serious especially in bad weather,such as the rainy weather.Traffic accidents occur frequently on rainy days,which will lead to the large casualties and losses.Therefore,the research on the operation and management of the rainy weather freeway is one of the most urgent problems to be solved.In terms of theory,the study consist of some highway traffic accidents and the management controls of the bad weather but mainly concentrate on the macro level which only provide the simple qualitative suggestions,which not involve the specific traffic flow model and mechanism characteristic.However,the existing traffic flow model cannot reflect the traffic accident under the bad weather and controls.An improved cellular automaton model(CAM)of two lanes one-way freeway are presented,where some vehicle accidents will occur when the necessary conditions are simultaneously satisfied.The freeway traffic accident probabilities are analyzed and the more elaborate road traffic flow control strategy are refined via the simulation experiments.The main work can be summarized as the following aspects:(1)The analysis of freeway system and traffic accidents on rainy days.According to the description of the freeway,the analysis of controllable and uncontrollable factors,the basic concepts of the rainy day are elaborated.On this basis,the affection of rainy day are described,especially the influence of the possible traffic accidents are analyzed.(2)The analysis of the micro-relationship vehicle dynamics of possible traffic accidents in rainy days.By way of analyzing the concrete model,the influence of rainfall for the driver,vehicle and road surface,the sideslip accidents of rear-end collision accidents are dynamics analyzed on the rainy days,the micro-relationship vehicle dynamics model of possible traffic accidents are established,which provide the research foundation.(3)The freeway possible accidents traffic flow CAM of the rainy day is established.On the basis of symmetric two-lane Nagel-Schreckenberg(STNS)model,the basic model are improved and optimized through the freeway traffic flow characteristics and traffic rules of the rainy day,the freeway possible accidents CAM of the rainy day are established.(4)Numerical simulation and the control signal applying strategy of the freeway on rainy days.According to the negative impact of the freeway traffic system on the rainy days,traffic flow of the entrance and VSL value are adjusted by the simulation experiment,which get the corresponding optimal the upstream traffic flow and VSL value that ensure traffic safety of freeway on the rainy day,take reasonable control signal applying strategy and provide some scientific and rational decision support.