2workigo t1_iy3y2z5 wrote
Reply to comment by indy_cision in Eli5 why do traffic lights have red, yellow and green color? Why not use other colors so that even colourblind people can drive. by [deleted]
I obviously haven’t had enough coffee yet because I don’t understand this. The placement of the lights is standardized. The three different colors are illuminated. Green is on bottom. So at night (or really anytime), if the bottom light is glowing, you know it’s green.
Antithesys t1_iy4aksf wrote
There are many environmental conditions, especially at night, where you see just a light and not the rest of the fixture, so if you don't know what color it is you can't determine if it's the top or bottom. It usually becomes apparent up close but until then you would need to guess whether you should be stopping or not, and we don't need people guessing on the road.
2workigo t1_iy4d4t9 wrote
Well that’s scary. Thank you for this TIL!
indy_cision t1_iy5rim2 wrote
When it is dark and you driving towards them and cannot see anything other than the one glowing light, how do you know if it is the top or bottom light that is lit if you are red/green colourblind?
2workigo t1_iy5xuv4 wrote
Yep. I don’t know why I didn’t think of that. In my area the vast majority of traffic lights also seem to be surrounded by street lights so the entire stop light is illuminated at night. I was hypocaffeinated this morning, that’s my excuse. Thanks for replying, it makes sense!
Viewing a single comment thread. View all comments