Study On Traffic Safety And Control Strategy Of Expressway Under The Coupling Effects Of Wind And Rain

Exposed to the nature, highway transportation is greatly influenced by inclement weather,such as wind, rain, fog and snow, which lead to traffic jam and serious accidents. Theproblems of reducing effects of adverse weather on transportation, improving the quality,reliability and efficiency of highway and ensuring the highway safety are highly concerned byhighway workers and managers. Based on “Study of traffic safety guarantee technologies ofexpressway in typhoon period” attached to Transportation Science and Technology Project ofZhejiang province, the respective and coupling effects of wind and rain on traffic safety areresearched, and their mechanisms are proposed, which provide theoretical support for safedesign and transport of expressway.Based on the extensive collections of research materials and data related to traffic safetyunder harmful weather, the control strategies and the research results of the effects of wind,rain on traffic safety are analyzed systematically. According to the defects and blankness ofexisting research methods, the main research content and technical route are proposed.Using systematical analysis method, the unfavorable effects of wind and rain on trafficsafety are illustrated comprehensively. According to their impacts, the types of wind and rainare summarized. Through wind tunnel experiments and selecting passenger cars and containercars as typical models, the uniform flow of wind field is simulated under the wind speed of8m/s,13m/s and the angle of0°,90°, the wind-force has been quantified. Thourgh analyinghydroplaning performance and comparing existing documents, the driving speed underhydroplaning and the road adhesion coefficient under part hydroplaning are obtained. Basedon meteorological monitoring data and utilizing mathematical statistics method, therelationship between visibility and rainfall is studied theoretically. The calculation model ofvisibility is established. The content in this essay provide theoretical basis for the followingresearches.Based on vehicle kinematic principle, the safe driving model of rigid cars under wind isestablished through theoretical analysis. As a result, the modified value of design standard ofminimum circular curve is calculated coupling with the consideration of wind effect.Combining the automobile structure and road condition, the mechanics of automobilesuspension driving on curve and slope section is analyzed systematically, and then modifiedmodel of safe driving under wind is established. Using qualitative and quantitative methods,the effect of wind on road condition, drivers’ reaction and automobile braking performance is fully analyzed; therefore, the calculation model of stopping sight distance on rain days is builtwith the consideration of comprehensive system of man, automobile, road and environment.With regard to the vertical and horizontal aspects, the calculation model of travel safety onrainy days is erected. Based on the effects of wind and rain respectively and usingsystematical method, their coupling effects are studied, and the calculation model of safedriving is built. The main content in this chapter provides theoretical basis for controlstrategies.Though summarizing the documents, the multiple factors influencing the safe drivingunder the effect of wind and rain are analyzed in depth. Considering the main factor, usingDEMATEL (Decision Making and Trail Evaluation Laboratory) as guidance, taking expertquestionnaires as auxiliary method, the key factors of coupling effects of wind and rain onsafe driving are screened out, and then the risk assessment system of safe driving is proposed.Using AHP (Analytical Hierarchy Process) method, the weights of indexes are calculated. Theimpact of every index on safe driving is studied, and each index’s evaluation criterias ispresented through qualitative and quantitative analysis method. The matrix model isestablished for fuzzy comprehensive evaluation, using it as a base, risk grade of driving safetyis proposed.Based on the drivers psychological and behavioral change, according to existing designforms of road marking domestic and abroad, research methods of facilities recognition areproposed and implemented. Analyzing the data, the traffic signs and road furnished withbetter recognition on windy and rainy days are obtained which provide the basis of optimizingthe transportation facilities. According to the risk grades of safe driving under the couplingeffects of wind and rain, from the two aspects of traffic control and construction measures, thecontrol strategies are presented. Comparative analysis method in the effect assessment ofcontrol strategies is adopted by completely analyzing existing assessment methods. Finallythe applicability of research results is verified by applying to support project.The research results provide not only theoretical basis for expressway design inwindy and rainy areas, but also technical support for expressway safety control andmanagement.