城市快速路交通流基础模型研究

he applicability of three conventional traffic flow models: Greenshields models, Greeberg models and Underwood models of urban expressway are researched. Based on field data from Beijing expressways, parameters of the models are determined. Besides, variable relation plots of field data and data calculated by models are drawn, such as flow-speed plots, flow-occupancy plots, and speed-occupancy plots. In addition ,the average of accumulate relative error between them are computed. It is found that the flow-density models of Greenshields can describe uncongested operation of urban expressway, Greeberg models can describe both congested and uncongested operations，otherwise, Underwood models are fit for congested operation.