I’m really surprised that no one ever wrote in and challenged Cecil on this, particularly since we all frequently look at traffic lights.
Go look at one, is that green light really green? Is that red light really red? Nope, they aren’t. That’s because the green is tinted with blue, and the red is tinted with orange. The 1 in a 1,000 traffic light that isn’t shaded like this is problematic for colorblind people like me, and that’s when you rely on red always being on top or the left.
I hope that since 1986 Cecil has learned more about his condition, the sheer amount of ignorance of the general population towards it never ceases to amaze me.
I’ve always wondered whether the tradition doesn’t come from shipping rules. The standard port-side light on a boat or ship is red, the starboard-side light is green. The ship on the right has the “right of way,” and when you’re on its left you see the red light. On it’s right, when your boat would have the right of way, you see the ship’s green light.
In other words, how old is that tradition for boats and ships, and did it influence modern automobile traffic regulations?
i agree with the comments of peoples ignorance towards colour blindness. ive known i was colour blind since an early age, and while im only approximately 50% (last time i was tested) it still causes problems. i remember one girl in my year 7 class asked me “how do you see green and red on traffic lights?” and everyone laughed, including myself. however, to this day i regret laughing at her, because every now and then i will look at a traffic light, only half concentrating, and not notice whether the top or bottom is lit, and be confused by the red/green and either think i should go before correcting myself or slow down when its really green. yet nobody understands how this could happen, because its so simple to pick the top or the bottom. but, ignorance being bliss, most people who make jokes or trick people because of their colour blindness, are very happy people
and ill never forget the times i coloured in maps with purple water my good friend always being the one to lend me a purple pencil when i asked for blue knowing i wouldnt be able to tell but even i found that funny.
While i dont dispute your overall explanation, there’s one very plausible reason that you seem to have overlooked… perhaps a case of myopia, in conjunction with your admitted dichromatism? (Look that up. I did.) My logic stems from long-since forgotten but recently recalled middle-school physics.
We all know that the reason the eye perceive colors is that the visible spectrum, per se, consists of a band of light of varying frequencies and wavelengths. (V-I-B-G-Y-O-R, anyone?). Red is at the low-end of the spectrum, and therefore has the lowest frequency in the visible spectrum… ergo it has the largest, or longest wavelength. (Since frequency of a particular radiation is inversely proportional to it’s wavelength).
Due to this brilliant fact, all things red are perceived by the human eye in greater contrast than any other color (as anyone who watches formula-1, and is blinded by the red-sporting tifosi in the stands, will attest). The color, red, due to its longer wavelength, is clearly visible from afar more than any other color in the visible spectrum, and so anyone approaching a stop-sign or red-light, will receive maximum warning from a red light.
QED.
(I will concede, though, that it is entirely possible that this is a lucky coincidence, as it is entirely possible that people had no idea of frequencies and wavelengths when they were establishing red as the accepted color for all things shouting Stop. As usual, I leave it to you to let me know if what Ive been banging on about has some scientific cred, or whether I’m just a loony. In any case, enjoy the little makeshift stop-sign smileys ive included at the bottom of this post.)
:mad:
:rolleyes:
When I took Industrial Engineering as a young tad, one of my courses was in Applied Psychology - in the faint hope that, if engineers understood more about how people percieve things, we might be able to devise better systems.
In this course, I learned that there are two common forms of colour blindness: protanopia and deuteranopia. Deuteranopia is the inability to percieve various shades of green, and the reason for a blue tinge being applied to the green lens on traffic lights - deuteranopes can see the blue, even if they don’t distinguish the green. Protanopia is the inability to distinguish red from green, or red from blue-green, so the tinted lenses don’t help there. So another visual cue is required, which leads to traffic signals where the red light is larger than the yellow or green lights. This works nicely for side-by-side signals as well as up-and-down arrangements.
Of course, not all traffic light designers are engineers, or took Applied Psychology courses, so there are still some traffic lights around that lack these additional visual cues.
but even i found that funny.
