Spillback is the full or partial blockage of an intersection by one or more cars that don’t make it through before the traffic lights turn red. 

“排队溢出”指的是交叉路口被一辆或多辆车完全或部分堵住，导致交通灯变红前路口一直无法通行的状况。

Spillback occurs when a street block is so jammed with slow-moving or stopped vehicles that it has no room for any entering traffic, which frequently "spills back". 

当街区挤满缓慢前行甚至停止不动的车辆，也就没有空间留给其他车辆驶入，这时就经常会发生“排队溢出”。

我们平时也常用queue spillback来表示下游交叉口车辆排队蔓延至上游交叉口的交通现象。