Daft Question of the week...

In this, the second question, I'm hoping we get more of the wacky types of answer I was looking for, rather than the "normal", "sane" answers from Max and Jenny. Why is it that traffic lights have the "stop" light red, "get ready" light amber and the "go" light green? Why can't they be a different combination of colours, depending on where you are, based on the local population or the national flag? San Francisco and Cape Town could then have pink, white and purple for their combinations; Saudi Arabia could have white and various shades of green; the USA could have red, white and blue (they've already turned the navigational light system around from the rest of the world - internationally green is to port and red is to starboard, but in the USA it's the other way round); Scotland could have tartan-based lights, depending on what clan territory you're in. Hell, South Africa could have any combination of six colours (red, white, black, green, yellow and blue) in addition to Cape Town's gay pride colours.