Mechanism Analysis And Mathematical Model Of Safe Driving Speed On Typical Ice-snow Road

the climate is very cold and the snowfall is stable in winter in northern China,the mileage of low-grade highway and substandard highway accounts for a large proportion of the total highway mileage in the northern cold region,and greatly improves the accessibility depth and transportation coverage of the road network,and provides support and guarantee for the development of national and local transportation industry and the safe travel of residents.However,low-grade and substandard highways in the northern cold region often have been covered with ice-snow for 3-4 months due to insufficient power to clear ice-snow,it is easy to cause traffic incidents or even traffic accidents due to motor vehicle drivers dominated by amateur drivers couldn't be able to control the safe driving speed when they encounter various typical ice-snow roads,which is a hot and difficult problem in the northern cold region.Traffic managers usually implement the regulations of speed limit on the execution of the road traffic safety law of the people's Republic of China by setting up static speed limit signs.When the road surface was covered by ice-snow,the fixed speed limit value can not meet the corresponding requirements due to the change of road condition;at present,in the theoretical,technical and equipment aspects of the research on the variation law of safe driving speed on ice-snow road,the domestic and foreign literature reflects that the discussion on the macro and management significance of the speed limit is relatively wide,however,there are few theoretical and technical researches on how to drive at a manageable safe speed when encountering all kinds of typical ice-snow roads and how traffic control departments provide adaptive safety speed limit for drivers.The research on the variation law of safe driving speed on ice-snow road is the key to solve the common hot and difficult problems in the northern cold region.In this paper,the mechanism of safe driving speed on ice-snow road was analyzed qualitatively,and the variation law of safe driving speed on ice-snow road was revealed from the theoretical level,and the test and analysis content of safe driving speed characteristics on ice-road was combined,and a mathematical model of safe driving speed on typical ice-snow roads was constructed.In this study,according to the driving speed and headway under different road conditions,the influence and intensity of different ice-snow road surfaces on traffic efficiency and safe driving state were analyzed,and the occurrence mechanism of traffic accidents caused by drivers' difficulty in driving safe speed on various ice-snow roads is revealed;through the mechanism analysis of safe driving speed,safe driving is extracted The key influencing factor of vehicle speed(adhesion coefficient),the formation law of adhesion coefficient on ice-snow road was studied,and the variation law of safe driving speed on ice-snow road was revealed qualitatively;in order to quantitatively describe the functional relationship between safe driving speed and adhesion coefficient,the test and analysis of safe driving speed characteristics on ice snow road were carried out.Firstly,the braking process of vehicles was analyzed,and then six types of safety driving speed were constructed;the relationship between safe driving speed and adhesion system on ice snow road is analyzed by testing the data of safe driving speed and adhesion coefficient on ice-snow road;the mathematical model of safe driving speed on typical ice-snow road was constructed by combining with the measured data and its characteristics,,and the function was analyzed;finally,the validity of the safety driving speed model was verified by Car Sim simulation software.The research has practical significance for guiding drivers to drive safe speed on ice-snow road,and also provides reference for the development of intelligent transportation technology such as speed guidance,dynamic speed limit and automatic driving.