Study On Simulation Model And Its Applications For Expressway Systems

The main content of this paper is simulation model of expressway systems. A highly efficient and convenient method is necessary for the research of expressway system. Though traditional methods such as field measurement and analytic derivation can deal with partial issues, the solution of simulation is superior to them for the complex road and traffic conditions in expressway systems. This paper analyses the characteristics of vehicles' moving in various components of the expressway. The existing models were adopted and improved to establish the integrated simulation system. The paper also describes the frame of the simulation system and the function of each model. The simulation system, which is established from the top down, contains input, simulation and output sub-system. Road environment, traffic environment, traffic control and each model are constructed with object-oriented method.This paper concludes the achievements of traffic simulation models. Some appropriate models are adopted for this system based on comparing each model in the theoretic and practical ways. The simulation system is validated as a whole model by comparing the data of the field measurement with that of the simulation. This paper discusses the applications of this simulation system in three aspects, including road alignment, capacity of expressway system and simulation of urban artery.This paper covers analysises of the traffic flow characteristics at basic segments, ramps and weaving areas, and the effects to free-flow by cross-sections, horizontal curves and vertical sections. The comparison and selection of car-following models, lane-changing models and free-flow models are also included.