Study On Highway Speed Limit Strategy Based On The Number Of Lanes Changed From Four To Eight

With the rapid development of highways, the security issue should not be overlooked. Speed limit is a key means of highway safety management, and it is of great significance to make reasonable speed limit strategy for giving full play to the advantages of highways, including high speed, safety, economy, comfort, etc. Under the current situation, where the contradiction between increasing traffic demand and limited highway traffic capacity is highlighted, highway rehabilitation and expansion provides a good idea for easing traffic pressure. Though scholars at home and abroad have a sufficient study of highway speed limit, the speed limit research aimed at rehabilitation and expansion highways, especially the highways with the number of lanes changed from four to eight, is relatively lacking.In view of the above-mentioned facts, this paper from the angle of theoretical analysis and practical application has a relatively in-depth research on highways with the number of lanes changed from four to eight and put forward the basic idea to formulate speed limit scheme of them, based on the project “Research on the Optimization and Effectiveness of Hebei Jingshi Highway Traffic Signs”(y-2011088). Meanwhile, the paper has established the process system to implement the speed limit strategy of the reconstruction and consideration highways.Through the analysis of research status at home and abroad, starting from the basic concept of speed, the paper expounds the relation between the main speed and limit speed, and the relation between the speed and road safety, as well as analyses the basic principles and implementation process of highway speed limits. At the same time, this paper focuses on the characteristics, advantages, disadvantages and applicability of the main means of highway speed limit. The above research provides a basis for the formulation of the speed limit strategy of a highway with the number of lanes changed from four to eight.According to the characteristics of rehabilitation and expansion projects and eight-lane highways, the paper analyses the speed limit bases and considerations of the reconstruction and consideration highways, and makes speed limit analysis respectively based on operating speed and old road accident data, as well as studies the establishment of speed limit scheme and the design of speed limit safety facilities. In fact, the whole research process provides a basic way for the formulation of the speed limit strategy of a highway with the number of lanes changed from four to eight: the design compliance verification of old road- the characteristics analysis of rehabilitation and expansion project- the speed limit analysis based on operating speed- the speed limit analysis based on old road accident data- the speed limit analysis of an eight-lane highway- the speed limit safety facilities design of an eight-lane highway- the establishment of speed limit scheme- the relevant suggestions, etc.In combination with the actual situation of the project, the paper has applied the above method to make the speed limit scheme of Hebei Jingshi Highway after its rehabilitation and expansion project. On one hand it verifies the feasibility and practical significance of the research results referring to the speed limit strategy of a highway with the number of lanes changed from four to eight, on the other hand it provides guidance and reference for the formulation of the speed limit strategy of this highway.