Green means GO!!

How did it come to be that green meant go . Why green? Why does yellow mean caution and red mean stop? Are these colors universal everywhere in the world?

The Master speaks.

Q: What does a yellow light mean?

A: Slow down.

Q: W h a t d o e s a y e l l o w l i g h t m e a n?

Or the way I drive…

Q: What does a yellow light mean?

A: Go faster.

Q: Whatdoesayellowlightmean?

(I don’t know how to make words look faster.)

For those of you too young to get the reference:

http://www.youtube.com/watch?v=pvn-tBeLpCk

Perhaps apocryphal, but I seem to recall hearing that during the ‘Cultural Revolution’ in China (ca 1967), attempts were made to switch from the “imperialist” green/go, red/stop, to the opposite pairings (indeed, in a good Marxist-Leninist society, red should mean go, no?).

The results of this little undertaking were as to be expected, and things quickly reverted back to the status quo (at least for those who survived :)).