International use of traffic lights . The Vienna Convention on Road Signs and Signals Treaty is the main reason why red, yellow, and green lights are used internationally. Ironically, the U.S and ...

The first traffic signals were not red, yellow and green. Here's why they are now. ... You’ve probably seen signs of them, buried in the pavement, as you pull up to an intersection,.

As kids, we learn the basic rules of the road using three distinct colors: red, green and yellow. Their safety connotations are ingrained in our brains from early on.