The Research On Moving Bottleneck On Expressway Based On The Cellular Automata Simulation

Because of the overloading of the heavy truck on the expressway of China becoming more seriously, there are more and more scholars and authorities concerning the loss of capacity of road section caused by heavy truck.The mechanism of the bottleneck's formulation is a dynamic procedure both in time and space, which was called moving bottleneck in the literature before. And because it's dynamic character in time and space, the moving bottleneck phenomenon is hardly to be detected and recorded. So the research of the moving bottleneck is mostly concerning the theory assumption.The main purpose of this paper is to research the formulation mechanism and the effort for the expressway capacity. Firstly, this paper review research methods on the issue of the effort heavy truck take on expressway capacity, especially the PCE(passenger car equality) theory. On the issues about the moving bottleneck theory, base on Newell's density-flow curve theory, this paper come some analysis indexes on the factors of the capacity loss caused by moving bottleneck,which is upstream vehicle density and the velocity of moving bottleneck itself.Cellular Automata (Cellular Automaton) is a method of evolution of the rules of cell-based bionic simulation. In order to prove the feasibility of simulation for the moving bottleneck based on the Cellular Automata. This article researched the time and space characteristics extracted from Daganzo's experiment based on the loop detector data, and the connection between the cumulative curve of the moving bottleneck experiment and the Temporal and spatial pattern of CA simulation.In order to observe the moving bottleneck's formulation which is changing both in time and space, this paper develop software for simulating. The software base on the Cellular Automata theory, use an Object Oriented programming method and Microsoft VC++ 2005 developing language. This software's input data and output data is visible, flexible, and can show the multi-direction of the moving bottleneck character.The core model of the simulating software is based on symmetric two-lane cellular automata (STCA) model. And in this paper, for make the STCA model more practical in the software, two innovations were made. One is a time safe variable Tn, the other is a space safe variable Pi. By analyzing the results of the software, the conclusion and assumption of this paper was tested and verified. Including And based on the simulating result, some suggestions were made for the expressway authority for improving the traffic safety and regulating the heavy truck traveling action.