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.
“排隊溢出”指的是交叉路口被一輛或多輛車完全或部分堵住，導致交通燈變紅前路口一直無法通行的狀況。

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”.
當街區(qū)擠滿緩慢前行甚至停止不動的車輛，也就沒有空間留給其他車輛駛入，這時就經常會發(fā)生“排隊溢出”。

我們平時也常用queue spillback來表示下游交叉口車輛排隊蔓延至上游交叉口的交通現(xiàn)象。

（中國日報網(wǎng)英語點津 yaning）