The red and green lights are a metaphor, they are not necessarily a rule.  The “green light” in a conversation, for instance,  is a cue that indicates the speaker is probably finished speaking. Usually, it is shown by the speaker saying some form of “Yes,” and nothing more, in response to my listening feedback:

e.g. “Exactly” or “Right” or “That’s it” or “No, I didn’t” or perhaps an affirmative head nod.

The “green light” is only an indicator. It is not an automatic clue to begin taking my turn to speak — OK, I did my listening. Now I get to talk.  See post, “How long to listen?”