Speed Limit Scheme And Driving Adaptability On Freeway Accident Segments

The scene of the accident occupied part of the lane after the traffic accident happened on the freeway.It not only reduces the traffic capacity,but also affects the driving safety of passing vehicles.When the upstream vehicles are near the accident site,they need to change lanes and reduce speed.If the traffic flow is high,it is easy to cause traffic congestion.The sudden deceleration behavior of some vehicles also brings potential safety hazards,which is easy to cause secondary traffic accidents and bring more serious casualties and property losses.It is of great practical significance and application value to deeply analyze the risk factors of the accident section,put forward the scientific and reasonable speed limit scheme,carry out the analysis of vehicle deceleration and lane changing behavior on the accident section,and study the adaptability of driving behavior under different speed limit schemes for improving the safety of the accident segments and avoiding secondary traffic accidents.Firstly,based on the theory of structural equation model,this paper studies the key factors affecting the safety of freeway accident segments and their influence degree.20 factors were used as observation variables and data were obtained through questionnaire survey.The reliability and validity of the data were analyzed and tested.Finally,the influence degree of 20 observation variables on the safety of accident segment is obtained.Secondly,according to the influencing factors of the accident segment,the scene models of different traffic volume,speed,speed difference and large vehicle rate are constructed by using VISSIM simulation software.The comprehensive accident rate model is established,and the number of speed limit signs that should be set in the accident segment is obtained.In order to maximize the comprehensive information benefit obtained by drivers,the maximum information benefit model is constructed.The location of speed limit sign on accident segments is calculated by using MATLAB programming and particle swarm optimization algorithm.Finally,the optimal speed limit scheme is obtained.Finally,the driving simulation instrument is used to compile the scene of speed limit scheme in accident segments.And recruit drivers to do experiments.The operation behavior of drivers in the process of deceleration and lane change on the accident section and the parameters of simulated vehicle movement behavior were collected.By analyzing 7 parameters of deceleration process and 11 parameters of lane changing process,the changing rules of lane changing and deceleration behavior of drivers on accident segments under different speed limit schemes are found.According to the analysis results of deceleration and lane change parameters,the driving adaptability of speed limit scheme 4 is the best.Taking driving experience and speed limit scheme as independent variables,variance analysis of 7 parameters in deceleration process and 11 parameters in lane changing process was carried out.The analysis results show that the speed limit scheme has a significant impact on seven parameters of deceleration process,such as the speed of deceleration starting point,the position of deceleration starting point,the position of deceleration to the initial speed limit value,and has a significant impact on six parameters of lane change process,such as the speed of lane change starting point,the speed of lane change ending point,and the duration.Driving experience has a significant impact on the four parameters of deceleration starting point position,average deceleration,deceleration to the initial speed limit value position and deceleration to the final speed limit value position,and has a significant impact on the five parameters of lane change starting and ending position.Then,the deceleration and lane changing driving behavior indexes which have an impact on the safety of the accident section are extracted by using the correlation test.The regression models of deceleration driving behavior and lane changing driving behavior on accident segments are established respectively.According to the results of the model,the optimization suggestions of lane changing and deceleration driving behavior are given.