Research On Policy Of Freeway Speed Management Under Adverse Weather

The weather is one of the important factors affecting the freew ay traffic safetyand efficiency. Bad weather can lead to traffic accident and road closure, cause hugelosses in people’s property and make people’s life safety in danger. Based on A lot ofdomestic and foreign literature on traffic weather and highway speed limit, the controlstrategies of highway speed limit affected by bad weather were studied.This paper first analyzes the influence of bad weather on road traffic drivingfrom two aspects of relationships, between vehicle speed and traffic safety andbetween bad weather and traffic safety. This paper mainly analyzed the adverse effectof two kinds of common bad weather (rain, fog) on traffic safety,and then draw thenecessity of the speed limit under inclement weather. The study showed that rainfallintensity, visibility and road surface friction coefficient are the main reasons leadingto the reduction of road traffic safety performance. Aiming at these reasons a schemeon road traffic survey on rainy days and an analysis on traffic characteristics of theobtained data are done, and analyzes the relationship between rainfall intensity andrunning speed, the relation between rainfall intensity and surface friction coefficient,strength and visibility of rainfall and short-time strong rainfall. In this paper, thevisibility, rainfall intensity and surface friction coefficient are the main parameters,based on these parameters, a calculation model of the safe speed of the vehicles on thehighway is proposed, this model is used to calculate the speed limits of recommendedvalues, and on the basis of it, the control strategies of highway speed limit under badweather are provided.This paper analyzes the speed limit set on the basis of various speed, such as thedesign speed, operating speed, make clear the importance of the running speed as themain basis of the speed. Aiming at the problems of highway traffic management underbad weather, put forward strategy improvement measures and suggestions of freewaytraffic management under bad weather.