关键词: 匝道层, 普通道路层, 快速路主线层, 控制子区, 主匝道, 从匝道

Abstract: In order to release traffic flow of urban road, a new hierarchical dynamic coordination control technique is proposed. Firstly, the whole urban road is divided into three hierarchies vertically：ramp hierarchy, ordinary road hierarchy and the mainline of urban expressway hierarchy. Then, BP neural network is used to forecast dynamic critical occupancy rate of downstream, and according to dynamic critical occupancy rate of downstream and the on-ramp queue length, the subarea partition function is designed, by which the ramp hierarchy is divided into the main control subarea and the secondary control subarea horizontally; the ordinary road hierarchy is divided into several control subareas horizontally by calculating correlation of adjacent intersection, and the Webster cycle formula is improved according to the dynamic traffic flow data, considering the traffic flow from intersection to ramp, the green ratio is optimized; the mainline of urban expressway hierarchy is not divided horizontally because of the lack of the intersection. Finally, the dynamic coordinated control algorithm is given and simulation shows that the proposed method can effectively improve the coordination control range and the vehicle speed.

Key words: ordinary road hierarchy, ramp hierarchy, mainline of urban expressway hierarchy, control subarea, main ramp, secondary ramp