Many signalized intersections in the United States are operating in oversaturated conditions during the morning and afternoon peak hours.Unlike under-saturated intersections,for which many wellestablished theories and signal timing policies have been developed,consensus has not been reached with regard to the control philosophy and timing strategy of oversaturated signals.For an isolated intersection,a common belief is that timely and efficient allocation of green time among the intersection approaches is essential to optimize traffic flows.A couple of the studies in the past have resulted in reasonable control policies that could possibly be implemented.However,the advantages and limitations of these strategies remain unrealized due to a lack of effective evaluation.This paper conducts an in-depth investigation to the characteristics and applicability of the control policies through thorough examination of two typical groups of classical models.The performance of the classic models is then compared with the latest versions of TRANSYT-7F and Synchro,upon which guidelines are made for effectively implementing signal control polices for oversaturated intersections.%在北美交通早高峰与晚高峰期间,大量信号灯控制的交叉路口会处于过饱和状态.对于非饱和路口的信号设计,已经有许多行之有效的理论方法和信号控制策略可以使用；对于过饱和路口,当前却没有被广泛接受的信号控制模型可以直接采用.对于孤立的信号路口,实时有效的配时通常被认为是优化交通流的一个非常重要手段.基于这一原则,多种过饱和路口交通信号设计方案出现在以往的研究中.但是由于没有对这些方法进行过有效的综合评测,所以一直没有对各种设计方法优缺点的清晰描述.本文对两组经典饱和路口信号设计模型进行了详细的评测与比较,进而深入分析这些模型的特点与可用性.在研究中这两组模型的控制结果还与最新的信号设计软件TRANSYT-7F和Synchro给出的优化信号进行了比较.基于比较结果,最终得到用于过饱和路口信号设计的方法选择指南.
展开▼
