The colours of traffic lights

I was cruising along on the bus this afternoon, staring at the many road signs and obstacles that passed by when I found myself hooked onto the traffic lights. I wondered to myself- as I do so often - why traffic lights feature the specific colours: Red, Amber and Green. We all know what they mean, red for 'stop', amber for 'get set' and green for 'go'. But have we had too much time to think about it and question, why these colours have these meanings? It may seem obvious for the colour red as it connotes danger, and perhaps even the end of a life, it is something where you would simply 'stop' because there is danger. However, I gave the colour amber more thought, because i couldn't understand what image/message it conveys. I was given the question about what colour is amber... is it orange or yellow? This twigged off more brain energy...the bit that I had left...amber hasn't made up its mind as to whether it's orange or yellow and so it is neither 'stop' nor 'go' but something in between. Finally, the colour green links to nutrition, health and growth and therefore this promotes the idea of the start of something, leading on to the word 'go'.

This is what I have decided makes up the colours for traffic lights, whether it's right or wrong, maybe another day I will find out.