左转错位交叉口信号配时策略的MILP模型

A MILP Approach for Left-turn Signal Optimization at Offset Intersection

在优化左转错位交叉口相位相序的基础上,提出了3套左转错位交叉口信号配时策略的混合整数规划(mixed integer linear programming,MILP)模型。MILP-1模型以交叉口通行能力最大为目标函数,以排队长度约束、最小绿灯时间约束、最大等待时间约束共同构成约束集合。MILP-2模型引入进口道重要程度的概念,修正目标函数,调整优化方向,以期获得最真实的配时方案。通过引入若干等式约束,可以得到简化模型MILP-3,并可运用分枝定界算法予以求解。广州市白云区金钟横云龙路口是一个典型的左转错位交叉口,分别运用MILP-1模型、MILP-2模型及MILP-3模型进行配时设计,求解结果表明:3个模型均能得到合理的优化结果,且以MILP-2优化效果最佳,MILP-3优化速度最快。

A MILP-1approach for left-turn offset intersection signal optimization is proposed together with optimized signal phases and sequences.MILP-1is to maximize intersection capacity under the constraints of queue length, minimum green time,and maximum waiting time.To improve the performance of MILP-1,a second approach named MILP-2is developed by incorporating weighting factors upon different intersection approaches.The weighting factors can alter the direction of the optimization so as to achieve a more practical result.Further,a simplified MILP-3model is presented by incorporating some equality constraints.Filed implementation using all the three models in Baiyun District, Guangzhou,achieved a relatively satisfying result:MILP-2performs the best and MILP-3runs the fastest.