LOS Evaluation Methods of Beijing Expressway Interchange Nodes

The interchange nodes are main parts of Beijing urban expressway system.Exploring evaluation methods and estimating the LOS of interchange nodes have great significance to identify the traffic jam formulation and propose relevant countermeasures.The paper analyzes main type and category of Beijing urban expressway interchanges and presents concept about urban interchange LOS.Then,using the index of travel speed,traffic volume of off-ramp and on-ramp,and speed of weaving and non-weaving sections,the LOS are evaluated for the main line,ramp and weaving sections.The LOS criterion is provided.At the final section,the Madian interchange,a very important intersection of Beijing urban expressway,is selected as an example to estimate its LOS and test the effeteness of the proposed method.