Abstract:The paper presents a theoretical model for estimating the capacity of signalized intersections with short lanes. The proposed model overcomes a shortcoming of current estimate models, which ignores the impacts of various short lanes. Three kinds of short lanes scenarios are allocated according to the characteristics of congestion firstly. The blockage process is divided into three stages including no blockage, probable blockage and after blockage. Finally, the calculation model for capacity of lane group is established and tested with the field data by simulation method. The intensive sensitive analysis on the length and number of the short lane, the spilt and cycle length reveal the impacts of short lanes on the capacity of intersection under different traffic flow levels.