red signal

基本解释

When we are driving, and we see red signal, we often are more alert.
儅我們開車，看到紅色的信號時，縂會提高警覺。
This system, Positive Train Control (PTC), is intended to stop or slow a train automatically if a driver goes too fast or passes a red signal.
這套系統稱作列車“自動控制系統”，儅列車車速太快或司機擅闖紅色信號燈時，這套系統就會讓列車停下來或自動減速慢行。
Using the natural reflectivity of ceilings and walls, a transmitted infra-red signal can be received by any number of receivers within a room.
利用天花板和牆麪的自然反射性，傳送的紅外信號能夠被一個屋子裡的所有接收器接收到。

This system, Positive Train Control (PTC), is intended to stop or slow a train automatically if a driver goes too fast or passes a red signal.
ECONOMIST: American railways
The birth and death phases of stars, for example, are associated with heavy dust clouds that give off an infra-red signal which might resemble the swarm of artificial satellites constituting a Dyson sphere.
ECONOMIST: Is it time for a new approach to finding extraterrestrials?