交叉口群信号宏观控制效率分析

Efficiency analysis of group intersection signal

为了甄别交通控制技术优劣,定义交叉口组织及相位方案、交通流结构和交叉口控制参数下的宏观效率,并将其数值化;建立基于宏观基本图分析的交通控制技术优劣甄别方法。以1条含有4个平面交叉口的主干路为中心的区域为仿真对象,根据仿真流量、速度、密度绘制宏观基本图,同时求出绿波信号方案、Webster最优周期方案、固定值方案下交通流速度的期望值,比较这3种交通控制技术的优劣。研究结果表明:在交通流由自由流状态逐渐加大并接近拥挤临界状态过程中,绿波控制方案能有效解决交通拥挤造成的车流速度降低问题,且对应的交叉口群通行效率最高;从宏观交通效率看,当交通流接近自由流状态或饱和状态时,Webster最优周期方案宏观控制效率比固定值方案的高;当流量处于限制流状态时,Webster最优周期方案对应的交叉口群通行效率与固定值方案的效率相近,两者的宏观控制效率无差别;所提出的宏观交通效率衡量指标能消除随机干扰所带来的小偏差。

In order to distinguish which one is the best among different traffic control technologies,macroefficiency definition and its calculation method were proposed in case of intersection organization and phase scheme,configure of traffic demand and control parameters.An arterial with four intersections was selected to figure out macroscopic fundamental diagram based on traffic flow,speed,density simulated on the whole arterial,and then the expectation of traffic speed on links was gained for green wave signal scheme,Webster optimal signal scheme and constant signal scheme.Lastly,the best one was distinguished by their expectation of traffic speed.The results show that when traffic flow is in the process from the free flow state approaching to saturation traffic state,macro-efficiency of green wave signal scheme is the best and the green wave signal scheme can cut down the dropping rate of traffic speed while the traffic demand increases.Only in the state of free flow and saturation traffic state,macro-efficiency of Webster optimal signal scheme is better than that of constant signal scheme.In the other traffic flow state,macro-efficiency of Webster optimal signal scheme is not prior to constant signal scheme,and macro-efficiency of the two schemes keep equivalent.Macro-efficiency definition and its calculation method can eliminate minor stochastic disturbing error to identify signal control scheme with essential improvement.