It also makes me feel less safe at night. I get that the orange glow makes everything look muddy, color-wise, but it doesn't kill your night vision to the same extent as the bright white LEDs do. Sure, things directly under the streetlight are lit up like it's daytime, but I can't see for @$#% in between the streetlights or behind the bushes or whatever.
I'm curious why it seems that no city has tried installing amber LEDs in an effort to try and realize the efficiency gains without quite so many of the downsides.
Flagstaff, Arizona did. There are some drawbacks, mostly that they simply don't get as bright.
https://arstechnica.com/science/2019/10/how-flagstaff-arizon...
“If you absolutely must use white LEDs, you could do what Tucson has done,” Hall said. “They... switched out their whole high-pressure sodium system to 3,000 degree white but reduced their lumen budget for street lighting from 480 million to, like, 170 million [lumens] or something. And you need to do that. For every white LED lumen, you're increasing your skyglow by a factor of about three, but they cut the lumen budget by about a factor of three. So overall, they managed to wash out the skyglow because they’ve got a lot of observatories down there.”
The extra blue is probably screwing up the circadian rhythms of humans and animals:
* https://www.health.harvard.edu/staying-healthy/blue-light-ha...
* https://www.npr.org/sections/thetwo-way/2016/06/21/482936520...
Efficiency regulations for residential fluorescent lighting delayed adoption by probably 25 years. Because regulations mandated lamps with terrible CRI.
I have an LED desk lamp with a temperature setting, and when it's on the warmer settings it really does produce a pleasant light.
Here’s a cutsheet for a Lithonia wall pack fixture showing the different options, there’s also a chart showing what the lumens per watt is based on the color temp: https://img.acuitybrands.com/public-assets/catalog/1008038/w...
"Tunable" LEDs are just multiple LEDs, the goal being to change the emission peak. Peak wavelength can be mapped onto a black body temperature trough Wien's law (λpeak =2.8e-3/T) https://en.wikipedia.org/wiki/Wien%27s_displacement_law
I don't really know how the mapping is done, though, as there are different ways to map it since the LEDs won't have the same emission curve as a black body.
The ideal for road safety would be more uniform lighting from a larger number of closer-spaced lamps, placed at lower height, diffused, shielded from the sides, and colored orange (and optionally uniformly dimmer).
It would also help road safety to ban the new bluer types of car headlamps, which cause much worse glare than previous yellower ones.
The color has almost nothing to do with that. Newer headlights are much brighter, and mostly use projectors now. The increase in glare is mostly due to the projectors, because they emit all their light from small point. You'll notice that newer cars with halogen projectors are almost as bad as one with HIDs.
It would be interesting to see how a headlight would look if it were able to emit the same amount of light on the road but from a rectangle spanning the entire front of the car. Minimum glare, still effective.
The color makes much of the difference. (What really matters is the total intensity in the shorter-wavelength part of the spectrum, so sure, making the lamps much brighter and less diffused is also bad.)
Shorter wavelengths cause significantly more glare, because the peripheral part of the human retina is packed with rods and S cones. Intense light including shorter wavelengths also causes the eyes to become bright-adapted, making it harder to see in the dark.
The super-bright halogen headlamps emit much more blue light than previous incandescent headlamps, and are included alongside LED headlamps in my complaint here.
Bigger, much dimmer, more diffuse lamps would help, but they should also be less blue. (And people should stop mounting headlamps on their SUVs and pickup trucks at other drivers' eye level and aiming them straight ahead.)
The night time lighting humans(and our non-human co-inhabitants of earth) have evolved with and known for a very longtime comes from fires of various types, flames with a much warmer color temperature.
Also, intensity is orthogonal to color temperature.
Consider the spread of lactose tolerance, a recent (no more than 10,000 years and perhaps less) mutation which has spread to 35% of humanity in that time. We have had plenty of time to co-evolve with fire, and doubtless, we have done so.
Its probably to do with cooked food, not vision - which is already co-evolved with the Sun, for when we are active/hunting/etc.
Wild animals very much do not. It's likely that our mucus membranes have also adjusted to the presence of more smoke: this doesn't prevent cancer, which is a post-reproductive problem for the most part, but it does keep smoke inhalation from being immediately debilitating.
Does it mean that fire doesn't fool our circadian rhythm into thinking it's still daytime? Sure, why wouldn't it? We've had a very long time to adjust, and getting appropriate amounts of sleep increases fitness in an obvious way.
We haven't had more than a hundred years of adjusting to bright blue-wavelength light after dark, however. So it could affect our circadian rhythm, and as studies show, it does.
I get that they’re cheaper to operate, but they throw shadows differently and have more blue wavelengths in them (in nyc they’re 4000 kelvin last I looked). It personally feels much less magical to me and 3-4 years in I still haven’t really gotten used to it.