27
votes
14answers
5k views

Traffic lights: why yellow before green?

Traffic lights around the world use the yellow light to warn people that it will soon turn to red, so that people can stop before. This is perfectly understandable. However, I found out that in some ...
27
votes
10answers
2k views

Traffic lights: “yellow” is progress, not state

When thinking about how (real-world) traffic lights work, I wonder if there is a more intuitive way to display the yellow light. The meaning of Green and Red are states: Green: Ok, you can go! Red: ...