I don't understand why red light is not the default for night lighting and street lamps and maybe even car headlights. Red light allows you to see while still maintaining your night vision. Blue or white or whatever other color you use will ruin your night vision and only allows you to see what is decently illuminated and anything outside that zone becomes invisible.
Technology connections (youtube channel) did a video about this. There was a trade-off between night vision and circadian rythm disruption vs driver safety.
Cooler light is better at keeping people awake and alert, and people drive safer when they are alert. Given that car accidents are a major cause od death, that is a hard point to compromise on.
The blue tint disrupts your sleep cycle and helps keep you awake when driving at night. There's definitely a trade off to be had depending on where these lights are located though.
It's not really the "blue" part. It's the "forcing yourself to be awake when you shouldn't be" part that disrupts your sleep cycle. Driving at night when you should be in bed is so much more the problem than whatever color the light is. For you as human at least =)
says what evidence? it's pretty much been debunked for a long time, and the whole premise is apparently based on bad science. I'm pretty sure i read an article here on hn that showed that this whole blue light scare was based on old science with extremely limited sample sizes and extreme exposure. i tried to link to an article from 2016 that still says that it affects sleep because i hastily read the first part. trying to dig up the article i read seems to be hard, but at least I'm still pretty sure that the science is not settled on the matter at all.
If you're referring to melatonin then the science really isn't that clear. Most light suppresses melatonin production.
One of the biggest arguments against blue light (specifically) being disruptive is that the sky spectrum in the evening is also blue (so naturally you'd be exposed to it). Modern airliners use blue lights for overnight flights with red lights at "dawn". I suspect screen brightness is more of an issue than any particular colour.
The dynamic range of the eye is confusing for aspects like this.
The amount of blue light you're exposed to from the night sky is trivial. Outdoors on a moonless night is 0.002 lux (of which, my understanding, about half is airglow and fairly blueish).
Compare to a not-too-bright single blue LED in your bedroom, emitting 0.5 lumens. You could spread that over 2000 square feet of surfaces and still have more blue light around than comes from the night sky.
The US Navy agrees with you, and is one of the reasons why interior lighting in ships/subs is red during battle so you can quickly switch between daylight and red without eye adjustment. Plus it looks cool.
Yeah I have red LED lighting in my boats for night lighting and also use the red light almost exclusively on my headlamp at night when camping, to maintain my night vision.
Our eyes are the least sensitive to it so it requires more light (which means more overall brightness, which actually makes your night vision worse and limits visibility of everything not lit, because your iris closes more) and it provides poor visibility/contrast and no color vision.
The only advantage red light offers is not disrupting your circadian rhythm.
Airplane instrument panels are lit with white. Saab, Volvo, and plenty of others use white or nearly white light for their dashboards.
Blue is used in theater only because it is less noticeable to the audience when it spills or reflects somewhere it shouldn't.
The real question is: especially with even 10 year old car headlights being so much better than the utter trash car headlights were 30 or more years ago, why are we still wasting so much energy, and impacting wildlife, and hurting millions of people's circadian rhythms, blasting streets with light all night?
There isn't even any argument in terms of public safety; there's never been any proof that lighting reduces crime. Lack of lighting forces people up to no good doing things where they shouldn't be, to use lights themselves - which stands out much, much more than someone doing something they shouldn't be under outdoor floodlights.
> why are we still wasting so much energy, and impacting wildlife, and hurting millions of people's circadian rhythms, blasting streets with light all night?
For pedestrians?
(I agree with your reasoning as it applies to highways, but most of the world's light pollution from overhead street lighting comes from lighting done either 1. within dense cities, or 2. within industrial complexes — in both cases to aid people walking around outside at night.)
As a pedestrian, I'd be much happier with a LOT LESS light at night. Though I have to admit that the overhead street lights aren't my biggest concerns (except for the newer awful white/blue LEDs). Car headlights are what really piss me off. Heck, even tail lights can blind me at night.
Bright night time lighting is often installed here as "security lighting". Meaning the bright light is primarily there to make people uncomfortable and not commit crimes.
The pink-orange glow of sodium bulbs was so nice and inviting compared to all these daylight blue parking lot projectors. I wish I lived somewhere where outdoor lighting needed a permit and the issuing authority rejected everything above X lumens or Y color temperature.
I actually find that my visibility on highways is worse for the parts that are illuminated by streetlights than for the parts that are only illuminated by my car.
I've found for example that it's extremely dangerous to go beyond 180kmh (110 mph) at night whenever there are street lights, while it's sort of ok if you just have side mirrors on the highway reflecting your own lights (not that I recommend to anyone to drive at such high speeds, especially in low visibility conditions).
> Our eyes are the least sensitive to it so it requires more light (which means more overall brightness, which actually makes your night vision worse and limits visibility of everything not lit, because your iris closes more) and it provides poor visibility/contrast and no color vision.
This does not match very common naval practices, nor my experiences. I believe the underlying mechanism is that the iris responds much more strongly to blue light because that is more prevalent in daylight.
Specifically this is about using red light to shine on things to see them. I could imagine that has very different requirements from the color of text on a HUD.
With red headlights you may see better, but other drivers (and pedestrians) are going to have a harder time seeing you, especially in daytime rain, which is half of their purpose.
Use a red flashlight (or filter) if you need to find stuff in a dark room without waking up the occupants.
And you'd be mad to put one at the front of your bicycle. In poor conditions, most any car driver would logically think the rider is travelling away from them.
(There are quite a few mad people in this world, having said that).
The Netherlands has many streets that are designed as "low car" streets or "bike first" streets.
The white lights are important for road safety but the Dutch have developed methods of softly discouraging the kind of traffic that makes the road dangerous.
This is especially common in residential areas. Most town centres are pedestrianized but retain brighter lighting as they can still be quite busy public areas in the evening.
But it takes about 45 minutes for your eyes to fully adapt to darkness.
So if we were to use red lighting at a level of illumination that assumes fully adapted eyes, it means people won't have sufficient brightneses for the first 45 minutes of their drive, which is likely most of it.
I only know that I adapt in about 5min. I read books in fbreader on a black bg and red text. The backlight can be very low in that app, depending on the phone you can read with an almost black screen. I start at 50% in five min I can it down to 10%.
Adaptation begins immediately but takes much longer to reach its full extent.
Go out on a very dark night and look up at the stars sometime. After half an hour, you'll be able to see stars that you couldn't see fifteen minutes ago.
