???????????????????????????о?

交通拥堵是当今世界的难题，而排队长度作为判断交叉口阻塞的标志，对其模型的研究具有重要意义. 针对我国混合交通的特性，结合交通冲突机理，首先考虑左转自行车对同向直行机动车的干扰，运用交通波动理论，提出了左转自行车对机动车干扰造成的排队长度计算公式. 在此基础上，研究红灯初期滞留车辆数的变化规律，提出了红灯初期滞留车辆数的动态计算公式，建立了适合于北京市实际交通状况的信号交叉口排队长度动态计算模型. 通过大量实验数据表明，该模型可行有效，在不同交通状态下均有较高的计算精度，为交叉口信号优化配时、缓解拥堵提供理论依据.

Calculating Model of Queuing Length at Signalized Intersections with Mixed Traffic

Heavy traffic imposes a burden to the day-to-day operation of the world. It is rather important to develop a queuing length model which reflects the traffic condition at intersections. Based on the characteristics of mixed traffic in China, the paper proposes a formula to calculate the queuing length of vehicles conflicted by left-turn at the beginning of green light using traffic wave theory and traffic conflict theory. Then, with analysis on delaying vehicles at the beginning of red light, a dynamic calculation formula is presented. Finally, the queuing length model at intersection with mixed traffic is developed for Beijing city, and which is suitable for dynamic calculation. The feasibility of the model is illustrated by empirical studies. The results show high accuracy at different traffic conditions. The proposed model provides a theoretical basis to optimize signal timing and reduce traffic jam at intersections.