A red light means get into position. Yellow light means ready.

VOA: standard.2009.09.10

It's no use talking about the negative relationship between a red light and a green light and a yellow, white, or blue one because they all have the same value.

讲什么它是红灯，不是绿灯,不是黄灯白灯一点关系都没有,它们所代表的意义都一样。

耶鲁公开课 - 文学理论导论课程节选

"It's putting a false sense on the market right now that everybody has this big flashing yellow light flashing, caution,caution,caution, so people are buying stuff you know in high volume than they usually buy.

VOA: standard.2010.05.08