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roughlytoday at 7:05 PM4 repliesview on HN

I'm reminded of an article a while back talking about how the change from sodium streetlights to LED streetlights had a whole lot of unforeseen effects on animals, people's sleep patterns, driver awareness and visibility, etc. due to color changes. There was a comment on the article from an old civil engineer saying "no, these were not unforeseen, we actually did the research back in the day to figure out what color the street lights should be, that's why they were the color they were."


Replies

SyzygyRhythmtoday at 7:33 PM

> that's why they were the color they were

That doesn't seem right to me. Sodium (and mercury) vapor lamps are the color they are due to physics, and were chosen because they're very efficient (and long lasting). Low-pressure sodium is the best and worst of these; essentially monochromatic but fantastic efficiency. Their only advantage, color-wise, is that the light can be filtered out easily (they used to be widely used in San Jose because Lick Observatory could filter out the 589 nm light).

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linkjuice4alltoday at 7:25 PM

I think we've learned a couple of times that lighting placement, temperature, and shadow-casting are not ideal [0]. Also some of the newer lighting does actually fade to a different color [1] so it's not just the base temperature of the new lights.

[0] https://en.wikipedia.org/wiki/Moonlight_tower

[1] https://sigostreetlight.com/blogs/common-quality-problems-in...

throwaway27448today at 9:09 PM

The posted article seems like credulous commentary, though.

cucumber3732842today at 7:30 PM

I'm sure tons of people along the way "noticed" but if you're selling LEDs or you're paid by the LED people to create marketing to convince people that LEDs are gonna save the planet, you're not gonna bring that up.

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