Interchange Capacity Model of Urban Expressway

Lack of research on interchange type, turning traffic volume and capacity becomes the reasons for unexpected interchange plan. In the condition of considerable expressway constructions with rapid traffic demand growth, this issue is extraordinarily prominent. The survey of traffic flow on three typical interchanges in TianJin has been completed; based on the collected desired speed, acceleration/deceleration both on mainline and ramps, and the VISSIM simulation model has been calibrated. Accordingly, the capacity values under various turning traffic flows on interchanges have been concluded. Furthermore, interchange capacity model has been provided based on the constraints of diverge area and weaving area, and recommended capacity values are presented for urban expressway compound interchange and cloverleaf interchange. This research has provided basic data for making standards and policies of urban expressway as well as the scientific basis for interchange type selection.