Why are traffic lights red, yellow, and green? Why weren't blue chosen? You'll be surprised to learn the real reason.

3. Green: The safest and calmest color. Green is the color most easily focused on by the human eye. It doesn't tire the eyes when viewed for long periods, so it's often chosen as a "go" or "go" signal.

Additionally, in nature, green is a symbol of “life, security, and peace”—a psychologically positive connotation.