关键词: 交通工程, 交通安全, 跟驰模型, 非线性拟合, 雾天, 安全距离

Abstract: In order to construct a car-following safety system aimed at the features of expressway traffic flow, the influence of the foggy environment on the car-following model and the establishment of the road safety standard were discussed based on both theoretical and simulation analysis. For theoretical analysis, it started from the fog level judgment, collected the meteorological information from different sections of the expressway by the fog monitoring system, and the fog levels were divided by fuzzy clustering analysis. And then it studied the sections of different fog levels separately. By mainly considering the influence of the visibility on speed and that of the road surface humidity on the friction coefficient, it obtained the relationship, and by the nonlinear fitting method, established the safety distance model of different foggy sections of the expressway. Based on this, it analyzed and obtained the models adaptability according to the running features of the vehicle, and the reference value of driving speed and safety distance on different road sections through the data fusion technology, which provides the theoretical basis for the driver's driving safety; for simulation analysis, it clustered and analyzed the meteorological information by using MATLAB and analyzed the error of the nonlinear fitting result by using Origin. The results indicate that the influence of foggy environment on visibility and humidity is relatively large, and the car-following model under an ideal state will no longer apply, which means the necessity to timely update the vehicle follow-up distance and speed limit and obtain the driving safety theory distance value suitable for different fog levels by modifying the model.

Key words: traffic engineering, traffic safety, car-following, nonlinear fitting, foggy environment, safety distance