Researching on Microscopic Traffic Flow Characteristics of Freeway under Rainy Environment

Existing models of traffic flow parameters are researched based on according to macroscopic traffic flow data, but the relationship among microscopic traffic flows parameters are not carefully investigated. Based on actual observation traffic flow data of freeway, to determine the probability distribution and cumulative probability distribution of microscopic traffic flow parameters(such as velocity, acceleration, time headway, lateral offset and so on)under rainy environment, and give velocity difference-velocity, acceleration-velocity, lateral offset-velocity distribution function above the law under rainy weather. Finally, validation results from the remaining data show that the distribution function can effectively describe the distribution of traffic flow under rainy environment, which can enrich freeway traffic flow theory, and provide a theoretical basis and practical value for the highway traffic management and control.