Traffic flow can be assigned on the generalized nets which include urban rail traffic nets and common bus nets,with the combined model of the modal split and traffic assignment.The authors put emphasis on description of the formation of generalized trip cost function and penalty coefficient and the average time of waiting for bus,and improve the link travel time function(BPR).The combined model for modal split and traffic assignment is put forward based on the generalized trip cost on the generalized nets,which satisfies user equilibrium.A multi-rails incremental algorithm simulates user equilibrium condition is proposed in order to increase the efficiency of algorithm,and a simple numerical example is presented.The combined model can real-timely show the relation between passenger flow of the road and trip time and quality of the public server.
