信号配时方案对交叉口承载能力的影响

为定量描述交叉口承载能力,并将交叉口几何结构、交通特性、渠化设置以及管制措施等影响因素纳入承载能力分析框架,对交叉口冲突车流进行分析,采用图论方法表达了基本相位集,并将承载能力的一般形式表达成等式方程组．随后以普通4路交叉口为例探索了临界承载能力的必要条件,最后建立了交叉口承载能力优化模型．结果表明:不同的信号控制方案对承载能力有着极大的影响,绿灯时间等饱和度分配本质上即为承载能力最大控制;对于一般的4路交叉口,信号控制车流的流量比之和等于2是交叉口达到承载能力的充要条件．

Influence of signal on the capacity of signalized intersection

In order to describe capacity of intersections, and take the factors such as intersection geometric feature, traffic flow characteristic, channelized section and regulation measures into account, this research exprersses the basic phase set based on graph theory through the analysis of conflict movements. Then the common expression of capacity is gven by equations. The four-leg intersection is analyzed as an example, whose necessary and sufficient condition is derived. At last, the optimization model of intersection capacity is established. The results show that the signal parameters greatly influence the intersection capacity. Equivalent saturation degree assignment is actually intersection capacity maximal control. For common four-leg intersection, the sufficient and necessary condition for capacity is that the sum of flow ratio equals 2.