Comments
Toes14 t1_iy3qeu5 wrote
Tradition. Red is the most easily/quickly recognized color, so it was assigned as "Stop". Green is opposite red on the color wheel, so it was assigned "Go". Yellow is in between those two and is also highly recognized, so it was assigned "caution - changing to stop soon".
Colorblind people CAN drive.
First off, there are different types of color-blindness, and not all of those interfere with interpreting the signals.
Also, stoplights are standardized so red is at the top & green is on the bottom. For horizontal lights, red is always on the left and green is always on the right.
dimonium_anonimo t1_iy3tbcu wrote
This tradition screwed heavily with me when I started working on industrial electrical equipment. Green means safe (off) and red means danger (energized). More common in Europe, but since the main mfg of equipment I was familiar with was an international company, we had to be well familiar with both options.
Toes14 t1_iy46fov wrote
That correlates to stoplights, since green means it's SAFE to go and read means STOP, due to DANGER of an accident.
dimonium_anonimo t1_iy47fnv wrote
But pray, tell, what button do I press to make my machine go? Red, or green?
nathan7356 t1_iy77h8a wrote
Green, for "all good, lets go!"
At least it should be, since e-stops are usually red for "crap, stop!"
There certainly are double-meanings here, depending on one's perspective and what one defines as "good" and what is "evil". Depends on if you're the operator or the mechanic, I suppose.
I see below that your machine seems to be the opposite. Most machinery I've seen has a green "start" button and a red "stop" button. I guess they're not as standardized as traffic lights. The hard part is when you press the green button, which illuminates the red warning light, lol.
ashank3 t1_iy4eylk wrote
Wait, this sounds like it’s still consistent with stoplights. Green means safe/off and you can interact with said machine (equally for cars, you can interact and drive through) whereas red means danger/energized (for cars, you should not interact with driving and stop the car). For me, this sounds like it checks out! 👍
dimonium_anonimo t1_iy4gp08 wrote
The counterintuitive part is that you normally think about things from the perspective of your car. Your car goes on green and stops on red. My machine goes when I flip the switch to red and stops when I flip the switch to green. If you think about someone else's car at the stoplight, then fine, this matches well, but I also think you're weird if you do that.
Fred2718 t1_iy4dywh wrote
Standardized...
Not always . There are still a few places where a horizontal layout is used.
Toes14 t1_iy4trl9 wrote
I didn't say that the more that the horizontal layout wasn't used. But in the United States, stop lights that are laid out horizontally always have green on the right.
indy_cision t1_iy3s06z wrote
And now for the missing info. The green is not green, it is a green/blue mix. This is so color blind people can see the difference, especially when driving in the dark (which all of the "green is at the top" people are ignoring - if you are driving at night and can only see the single light, the red and bluey green are still different)
Kalel42 t1_iy3sko3 wrote
I'm colorblind and the green doesn't even look green to me. It's more like white to my eyes.
sakzeroone t1_iy3u4dm wrote
How do you know?
Boy-from-the-dwarf t1_iy53nfx wrote
I, too, am colorblind. The new ones are definitely easier to see, but older lights suck. I legit couldn't tell the difference in color back in the 90s. Thankfully, those are few and far between now.
2workigo t1_iy3y2z5 wrote
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!
9600n81 t1_iy4aryb wrote
Red is at the top.
If you're close enough to a light that you have to obey it but can't distinguish the top from the bottom you've got bigger sight problems than colour blindness and probably shouldn't be driving at all.
indy_cision t1_iy5ryy0 wrote
Spoken like someone who hasn't driven in poor visibility conditions or dark enough to not see anything other than a single glowing light...
9600n81 t1_iy7hzqa wrote
Get an eye test or give up your licence.
enderverse87 t1_iy3q3cw wrote
Tradition. There are better colors possible, but now these ones are the ones everyone is used to and there's no way it would be possible to change all the lights at once, and it would cause a lot of accidents to have only some changed.
Spiritual_Jaguar4685 t1_iy3qela wrote
The colors were chosen for their ability to stand out from natural background lighting and for the general human ability to see them. (Red and Yellow are naturally easy for the human eye to see).
Finally a colorblind person wouldn't be impacted since the they can just count the lights. The top light is "stop" and the bottom is "go" regardless of color.
Mastodon996 t1_iy3shf3 wrote
Years ago I read somewhere that green lights have a fair amount of blue mixed in to give the colorblind a better chance of distinguishing them. Anyway, full colorblindness, as in only seeing in black and white, is very rare. Most colorblind people can function just fine.
tenormore t1_iy4cq6n wrote
Yes, I have a form of red-green colorblindness and I see traffic lights just fine.
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Kalel42 t1_iy3pews wrote
Colorblind people can drive. Even if they can't distinguish the colors, the order of the lights is consistent and can be used to determine which light it is.