兩盞交替閃動的紅燈，設於交通偶然需要中斷的地方，例如消防局出口，所有駛近車輛必須停下，直至兩盞紅燈均停止閃動。
A pair of alternately flashing red lights (wig-wag), used where traffic is stopped only infrequently such as at fire station exits, requiring all approaching vehicles to stop until both lights have stopped flashing.