Study On Driving Behavior Characteristics In Fog Environment Under Constrained Conditions

With the rapid development of China’s social economy and the continuous growth of car ownership,the road traffic accident rate is still high,especially in adverse weather conditions,road traffic safety has become a common concern and a hot research topic in the field of transportation.In foggy weather,the driver’s vision is limited,which seriously affects the driving speed,trajectory and headway.It often leads to chain collisions of multiple vehicles and serious injuries and deaths of drivers.Reasonable restriction of driving behavior is the main measure to ensure traffic safety in foggy weather,With the rapid development of vehicle-road collaboration and vehicle-vehicle collaboration technology,it provides technical support for traffic management such as speed limit,lane-keeping and safe distance between vehicles.Thus,in this paper,the driving behavior characteristics under typical constraints are studied.The driving simulator is used to study the influence of single and double constraints on driving behavior in foggy environment.The safety speed limit in foggy environment is revised with driving behavior questionnaire,which provides a scientific theoretical basis for traffic safety management departments.The main contents of this paper are as follows:(1)Investigation and analysis of autonomous driving behavior.With the constraint of driving speed,headway and lane-keeping,the Manchester questionnaire was modified into a driving behavior questionnaire which accords with the foggy environment.The reliability and correlation analysis of the questionnaire were conducted to prove the reliability and validity of the questionnaire.Drivers are divided into conservative style,general style and aggressive style by using the scores of violations in the questionnaire,which lays a foundation for the later classification of driver’s style and speed limit correction;(2)Design of driving simulator simulation experiment.Based on UC-win/Road,a driving environment with visibility of 500 m,200m and 50 m was built,and Blue Tiger driving simulator was used as an operating instrument to conduct simulation experiments.Design a straight-curved urban expressway with multi-curve radius.A single-constraint and multi-constraint driving scheme was designed.Forty-six drivers were recruited.Driving behavior data were collected according to driving experience and gender classification.Mind Ware multi-channel physiologicalrecorder was used to record drivers’ psychological indicators;(3)Analysis of driving behavior characteristics.By comparing and analyzing the differences of driving behavior indicators under different constraints,the operational behavior and psychological characteristics of drivers in foggy environment are obtained.The result shows that visibility,driving experience and their interaction have a significant impact on driver’s driving behavior,while gender has no significant impact on driver’s driving behavior.Driver’s vehicle control in the curve phase is significantly lower than that in the straight phase.In the single constraint experiment,the driver’s vehicle control ability is significantly higher than that in the multi-constraint experiment;(4)Classification of driving style in foggy environment and revision of maximum speed limit.In the previous model of speed limit in foggy environment,driver’s factors were taken into account and driving behavior factordk was introduced.According to the scores of violation of the questionnaire,drivers were divided into conservative,general and aggressive drivers.According to the speed data in the experiment,driving behavior factors of three styles of drivers were calculated,and the model of speed limit in foggy days was revised.Among them,the maximum speed limit of aggressive drivers is 62.64% higher than that of conservative drivers..