Study On Car-Following Model Of Xinjiang Freeway Under The Snow Weather

Our country is a large country which spans five time zones and each region presents different characteristics of climate with the season changes; also, the special weather has great influence in highway transportation. In China’s Xinjiang region, where has long winter and heavy snow, in some areas, the snow time even maintains for 3 ~ 4 months, the snow’s impact to the road especially to freeway is particularly outstanding. Therefore, to solve or alleviate the traffic problem through the study of traffic flow theory has both important research significance and practical value.First of all, based on the existing car-following model research both at domestic and abroad, this article sums up the existing research results as well as determines the research content and method of the following model under the snow weather through the most fundamental traffic flow theory and models.Secondly, this article introduces the basic concept and characteristics of car-following model, and makes a detail investigation plan based on the characteristic of freeway, and makes a traffic investigation combining with several common weather in Xinjiang(normal, rain, fog, light snow, moderate snow, and heavy snow) at the same location. In addition, this article introduces the survey method and announcements under special weather, providing a referential survey scheme for correlative research, and doing in-depth research with the free flow speed, average speed, time headway, as well as the relationship between speed and time headway that traffic flow parameters can reflect the following characteristics, to analyze the characteristics of traffic flow under different weather, to summarize the impact of different weather on traffic flow rule, and to provide a basis for the construction of model data.Thirdly, on the basis of the existing models of following research theory, optimize the full speed difference model, and combining the characteristics of Xinjiang freeway traffic under snow weather, this thesis improves the sensitive coefficient, and adds a influence option of space headway to acceleration, and improves the influence of the expected speed, while the minimum safety distance model was constructed by using the kinematics principle. Then, this thesis carries on the preliminary modification to optimize the velocity model correction, construction with car-following model, making it more in line with the state of traffic flow with car-following snow weather.Finally, in order to build an applicable following model for Xinjiang freeway, on the basis of the survey data and the preliminary model, this thesis identifies the snow weather in Xinjiang freeway car following model parameters, and verifies the gradual stability of the model through comparing the actual measured value simulation test to with local stability and acceleration’s asymmetry. In addition, this thesis also validates the correctness and feasibility of model for the management of the transportation department under the ice and snow to provide theoretical basis and reference.