Because red light are used for tail lights, which you also see when driving. Different light colors allow you to tell if you are looking at the rear or front of the car.
this post was submitted on 03 Jul 2023
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Kind of shocked this logic isn't obvious. Red lights on cars in low-light conditions already have a very specific, very important meaning.
Yeah but it'd be nice if we went back to lights occupying the yellow area of the spectrum instead of the blue area of the spectrum. Bkinding I tells ya
Also, we need to be able to read and recognize traffic signs, and those are often color-coded, red having a very important meaning. With red head-lamps, all traffic signs would be red-and-black at night, great !
Red light is great for a headlamp when you want to preserve your night vision, you're also walking instead of traveling at +60 mph. Red light also doesn't provide you with any color differentiation which would be an issue with already existing road lines (yellow vs white) and street signs along with the simple notion that humans are used to light in the full spectrum from the sun.
The biggest issue with headlights is people putting LED lights in older, halogen bulb housings that don't scatter the light the same as LEDs which leads to blinding lights that are quite bright. Additionally, you get those assholes with lifted trucks that don't re-aim their headlights and they too add to the annoyance and danger of driving at night.
Better enforcement of existing laws would help, but that's asking a lot of police these days when they seem to have so many other "better" things to be focusing on. /s
Red lights don't allow you to see as well in dark/poor visibility conditions that are needed for driving. You're moving 30 to 60 mph likely on the road vs walking speed while hiking and that reaction time visibility is much more important. The intensity of red light that would be needed would make the benefit non-existent (as they'd be just as obnoxiously eye-destroying as the super brights and blue lights).
Some states in the US allow "amber" colored lights for headlights/brights though, and I think they're way less obnoxious and still allow for high levels of visibility.
I imagine we need close to white to differentiate colours, see this video for more information on that.
However, the LED lights are way too bright, usually when I see an incandescent headlight its fine, but the LED ones are so bright and I have no idea why that is. I have a recollection of reading somewhere that headlight brightness is based on a unit based on a wavelength of light closer to orange, so the more blue a light is, the brighter it needs to be, but I can't remember for sure.
I hate those blue lights. 🤬 did t they make one of them illegal? (US)
Yes, those lights you are talking about are illegal. Same with vehicles that have too high of bumper heights and too low. Unfortunately, a lot of traffic laws don’t get enforced
I am assuming you mean the cool white xenon lights, not blue like police lights. Xenon lights are totally legal. Some places may have laws on the maximum candela of a headlight.
Two points to mention:
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Some people are installing Xenon light bulbs into Reflector type headlamp assemblies. This is highly dangerous, and should be considered illegal if it isnt already. Xenon, HID, and LED lights should never be installed into reflector type headlamp assemblies, only projector type.
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Light adjustment. Most people dont know this is a thing, and its why you get these ding dongs blinding everyone on the road. Headlamps need to be adjusted so they point towards the road, not at incoming drivers eyes.
The lights, themselves, aren't always illegal. Some of them are. The ones that are obviously emitting blue light are definitely illegal, but the ones that are just so bright that they "feel" blue are typically completely legal.
The problem with those lights is that they're often not installed properly. A lot of inexperienced car owners will install HID lights without the proper housing device, causing the lights to point at an incorrect angle (causing the blindness when one of them tailgates you) and making it so that they don't disperse the actual spectrum of light properly (causing the blueness).
It's often further exacerbated by the fact that the people who do these shoddy installations are the same people who drive pointlessly lifted vehicles and like to really ride your ass at night, blasting that laser beam of blue death straight off your rear-view and into your retinas.
Unfortunately, enforcement on these things is basically nonexistent.
When I was growing up, back in the Paleozoic era, I'm pretty sure it was illegal to have a red light on the front, white light on the back(except for backup lights), and blue or green were illegal anywhere on a vehicle. But all that seems to have gone out the window since then.
Of course any vehicle that's been modified to produce excess smoke violates federal (EPA) and possibly local law, but we see how well that's enforced.
If lights wouldnt chase away wildlife there yould be more animals killed on the roads.
WaPo article in case anyone cared : https://www.washingtonpost.com/climate-environment/interactive/2023/firefly-summer-extinction/
Actually, you can't "see fine" with the red lights. Sure, once your eyes adjust to the darker light, you can see at some level. But the red light doesn't allow you to see anywhere near near as well as you can in a white light. also, if you have poor night vision, red light isn't very good at all. And, the biggest reason why you can't use red headlights is color blindness. There are people who would be completely in the dark with those headlights.
That's... Not how color blindness works.
As a colorblind person red light still works for me
How early did you sign up to get this username. Awesome
Usernames are only unique per instance. So it's easy to get any name you like on smaller instances.
Aha thanks, of course. Still learning over here lol
Yeah. I was so stoked when I got this name before I learned how it all worked
Hmmm for some reason it says my username is Lemmy on some instances I'll have to fix that
Isn't there some specific color blindness that would make people unable to see reasonably under red light because they lack red cones and the other cones aren't sensitive enough at that wavelength, so they'd effectively be seeing like a normal sighted person would see with only 10-20% of the light that's present?
Shouldn't affect the area outside the fovea since there are also rods but that's not too helpful.
I'm not personally colorblind, but lots of men on my wife's side are, including my son. My understanding is that it doesn't affect brightness, it affects being able to differentiate colors.
It's important to note at this point that we're talking about mixing dye or paint colors, which behaves differently than mixing colors of light. When you mix red and green light, you get yellow. When you mix red and green paint, you get brown.
So to my son, for example, when you have an object with a mixture of mostly red and a little green - I would see that as "mostly red with a little green," while he would see it more like "brown." My expectation would be that if he was in an otherwise dark room illuminated with only red light, that he would see objects with a similar clarity as I would, but that his experience of the color would be different from mine in a way that I could never really understand (and vice versa).
Since I have access to a relatively large number of colorblind people, this makes me want to do an experiment.
Just read the WaPo article before posting. The article didn't specify which type of light sources cause the issue. Is the car headlights different today compared to decades prior? If we can switch bulbs to the older ones, what would it take?
Is it the strobe light effect of the LED light source or simply the color white/blue itself? need more information.
In the defense of blue light, it will help keep you awake
It's because car light colors are actually just the Doppler Effect in action. When a car is coming toward you, its lights look white. When it's moving away, its lights look red. This is also why when your wife or girlfriend is shrieking and running towards you with a knife, her voice sounds very high.
This is a really good "explain like an idiot" account of Doppler effect. A++++ would upvote again.
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