Abstract: To alleviate the ever severer congestion problem in weaving section of urban expressway,a discrete model of multi-lane weaving section was built based on CA and consideration of the influences of temporary driving-out vehicles,the factors of vehicle lane-changing safety clearance and lane-changing behaviors.Furthermore,simulation experiments of the evolution of traffic flow in multi-lane weaving section under saturated condition were carried out,and a formation mechanism of congestion in the weaving section was analyzed.The model was preliminarily validated by comparing the traffic obtained by the simulation experiments and that in actual statistics.It is shown that the model of multi-lane weaving section can reproduce the traffic flow in the weaving section more reasonably,that the regular driving-out vehicles and the temporary driving-out vehicles have great influences on the traffic flow in the weaving section,that among them,the temporary driving-out vehicles are characterized with suddenness,which has a serious impact on the capacity of the weaving section,and that in order to maximize the capacity of the weaving section,whose length should not be less than 150 m.

Key words: urban expressway, weaving section, traffic flow, lane-change, cellular automaton model(CA), traffic simulation