6 ms·
US Streetlights Are Turning Purple
- Simulacra 1y agohttps://archive.ph/6xm8M https://archive.ph/6xm8M
- mrtksn 1y agoHere's a video on the topic from 2 weeks ago: https://www.youtube.com/watch?v=Jfr8fmF8oJU https://www.youtube.com/watch?v=Jfr8fmF8oJU Pretty interesting.
- clumsysmurf 1y agoA Trader Joe's in Phoenix has had these for so long (years?), the parking lot is bathed in almost completely blue light. They don't seem to care. It really throws off your vision and things look "fuzzy".
- sidewndr46 1y agoMaybe it's just me but the actual color of the light never bothered me. The first time I saw it I figured out it was a form of LED failure. It's so common here that I don't think about it anymore
- pxndxx 1y agomonochromatic light as emitted by LEDs is quite disorienting.
- sidewndr46 1y agoI grew up in the generation where every manufacturer decided blinding bright blue LEDs were standard features of all consumer electronics. Maybe I am just desensitized to it?
- CalRobert 1y ago“ producing light that is comparable or better in quality.” They don’t support this claim about led’s, and many groups are concerned about harsh cool light interrupting circadian rhythms. They’re also hideous.
- BorgHunter 1y agoIt depends strongly on implementation. LEDs can produce white light at any color temperature and CRIs ranging from terrible to great. Quality LEDs are quite nice indeed (when they're not turning purple). Most LED streetlights replaced sodium vapor lights, though, which produce the sickliest, most horrible orange color known to humanity. Just about any LED is an improvement over those.
- hedora 1y agoSodium lights aren’t even orange in the normal sense of the word. They only emit one wavelength.
- wiredfool 1y agoI thought it was two - the sodium double emission line.
- adrian_b 1y agoThe lines are so close that their hues cannot be distinguished by a human eye.
- addaon 1y ago> Sodium lights aren’t even orange in the normal sense of the word. They only emit one wavelength. It's hard to think of a more normal sense of the word "orange" than "emitting and/or reflecting predominantly wavelengths between 590 and 620 nm." I guess you could argue that sodium is close enough to that lower edge to be yellow?
- looofooo0 1y ago
- osigurdson 1y agoTL;DR - coating is wearing off.
- xxs 1y agoSure, white LEDs are blue LEDs with a phosphorus layer. The Blue LED invention led to the 2014 Nobel Prize for Physics.
- waltbosz 1y agoI (and my 6-year-old) really enjoyed this video from Veritasium about the invention of the blue LED. https://www.youtube.com/watch?v=AF8d72mA41M https://www.youtube.com/watch?v=AF8d72mA41M
- downboots 1y agoThe fix is incredibly simple https://www.youtube.com//watch?v=4Mll-YDDAF4&t=678 https://www.youtube.com//watch?v=4Mll-YDDAF4&t=678
- echelon 1y agoBetter article with lots of pictures and diagrams, links to conference talks, etc: https://inside.lighting/news/24-05/heres-why-led-streetlights-are-turning-city-highway-purple https://inside.lighting/news/24-05/heres-why-led-streetlight...
- ipdashc 1y agoThank you, this has been happening near me for years now and I've seen countless news articles on it, but this is the first time someone's actually linked what looks like an authoritative source (or at least anything that goes into more detail than "the phosphor is falling off... or something").
- modeless 1y ago> people driving at night may notice a moving object in their peripheral vision more quickly under bluish-white light than under yellowish-white light, [...] Gaining improved peripheral vision under blue-tinged light comes with a trade-off, however: once the moving object comes into focus, it becomes harder to see. If we were switching away from LED to sodium vapor lamps instead of the other way around, they would have written the exact same article but in reverse, still claiming the change makes us less safe.
- deleted 1y ago[deleted]
- PedroBatista 1y agoNo, sodium vapor lights offer great performance in terms of contrast and visibility. Especially in bad weather conditions.
- robertlagrant 1y agoYes but that's the point: sodium vapour offers worse peripheral vision, so it could make some situations riskier.
- metalman 1y agono way, once something is into your periferal vision while in a moving car it's too late, and fact does not matter....unless it's moving realy realy fast, and then it's still too late so the real equation will involve all sorts of other inputs, like the coulor temp, and amount of direct vs reflected light, background light conditions, weather, and indivual perception of any given driver. *green light is the worst, as our eyes have the greatest sensitivity to it, and out night vision adaptation is to the black and white(muted coulor) light that is natural. current regulations are ancient, but there is no reason that a non opiniated solution cant be figured out and implimented
- supermatt 1y ago
- joshstrange 1y ago> And yet some streetlights have suddenly turned a jarring shade of purple. It is hard to determine the exact cause without dissecting one of the defective lights, but scientists have a hypothesis: bright purple light suggests the phosphor layer around the lights has been “delaminated”—peeled off—exposing the blue LED light underneath, Brgoch says. What an annoying/bad article. "Here are our guesses of this when we could have actually figured it out". It's not like these are in space and hard to get to, they are on the freaking street. Get a crew out there and figure it out. Then they go on to do a _bunch_ of handwavy "science" about blue light while not really making any point (IMHO). > One thing that Bullough suggests pedestrians and drivers do to stay safe under purple streetlights—or any lights, for that matter—is to remove sunglasses and blue-light-filtering glasses when walking or driving at night. Ahh yes, for all the people that wear their sunglasses at night, I'll make sure to let Corey Hart know. This just seems like an incredibly low-effort article with zero definite facts and enough hand waving to sprain your wrist.
- neutronicus 1y agoFWIW I do wear sunglasses for long highway drives at night. Without them halogen headlights in my side mirrors give me a migraine after a while.
- jessriedel 1y agoFYI you can get auto-dimming side mirrors (same mechanism as for rear-view mirrors). I presume it’s a pain to install them after-market, but it can be done and maybe worth it for you if brights bother you enough to wear sunglasses.
- sokoloff 1y agoWhen I had some window tinting done on a car, they tinted the side mirrors at no extra charge with excess film. At first, I didn’t like it, but quickly grew to quite like it. (It’s pretty much only annoying for seeing the curb while parallel parking at night.)
- hoseja 1y agoThis is wrong about phosphors in the initial explanation, no? They are actually quite broadband AFAIK.
- RDaneel0livaw 1y agoone of the biggest roads in my town has these purple lights at night, and it's very off-putting honestly. Makes it kind of hard to see things properly. I specifically avoid this road at night now because of it.
- padjo 1y agoIt’s a fairly common failure it seems. Here’s it happening in Ireland: https://www.irishtimes.com/ireland/dublin/2025/02/05/almost-250000-spent-replacing-street-lights-turned-blue-by-catastrophic-failure/ https://www.irishtimes.com/ireland/dublin/2025/02/05/almost-... I had someone complain to me about how it was a change made by the Green Party for bats: how ridiculous! No, it’s just a faulty light…
- msgodel 1y agoI was told it was to make it hard for people using needles to find their vanes. It turns out it's just the phosphor coating coming apart. The LEDs used to energize that to make the broad spectrum light are usually blueish purple for maximum efficiency.
- cogman10 1y agoIt does do that and it's used for that. I first experienced that in a bathroom in England. Door open, regular white light. Lock the door, blue light. I thought I broke something when that happened.
- davidmurdoch 1y agoRead somewhere a few years ago this was a manufacturer defect and they were in the hook for replacing them all. I've (not seriously) considered buying a pellet gun to shoot out the 4 massive neon purple lights at the entrance to my quaint 1970s era neighborhood. They didn't remove the old light poles after installing the new ones about 3 years ago, so it's double lit with sodium vapor and purple now. Curious is there is a single person on the planet that prefers the white (er, purple) street lights?
- kragen 1y agoI haven't tried them, but they sound awesome.
- malfist 1y agoSingle wavelength light is easier to remove or filter out for astrophotography than broad-spectrum light. But driver safety is probably way more important than my hobby
- worik 1y ago> Curious is there is a single person on the planet that prefers the white (er, purple) street lights? Yes One at least, me (I've never seen this failure mode, so I mean the LEDs) I especially like the reduction in light pollution
- davidmurdoch 1y agoI don't understand, you prefer the new LED lights but also like reduction in light pollution? The LEDs way brighter, so I'd think you'd prefer older lights. I'd guess about 20% of the lights in and around Orlando are purple now. Maybe the heat and UV makes it worse here?
- worik 1y agoModern LEDs direct more of their light down, less up to the sky, so yes, much less light pollution Also they are better suited to their job so need less light. Sodium lights are nowhere near as flexible so are worse, mostly, on both counts
- guicen 1y agoIt’s interesting how many people assume these purple lights are some kind of new design choice. But really, it’s just a side effect of the phosphor layer breaking down in the LEDs. Makes you appreciate how tricky it is to balance cost, lifespan, and quality when you’re manufacturing millions of these for cities.
- ankitml 1y agoDesign choices must include failure modes. IMHO, utterly stupid to only consider happy path.
- mrguyorama 1y agoIt also makes you realize just how willing the general public is to think that you are some conspiracy to ruin their lives, rather than being unintended.
- ribcage 1y ago[dead]
- Daisywh 1y agoTo be honest, I quite like this atmosphere. Some roads near my home now feel like something out of a science fiction movie when walked on at night. Of course, traffic safety may not be good, but walking at night adds a sense of fantasy.
- gaborcselle 1y agoTldr “ bright purple light suggests the phosphor layer around the lights has been “delaminated”—peeled off—exposing the blue LED light underneath, Brgoch says. Although blue LED lights are, in principle, deep blue in color”
- fennecfoxy 1y agoI've never seen a LED streetlight turn people where I live. Sounds like bad light design and the LED is perhaps getting too hot. Though that said, just go and replace them as they would have had to for sodium vapour lamps they had before? And this time replace them with something that runs them at a lower temperature, especially if the environment during a summer could be hot from external temperature.
- flyinghamster 1y agoAll of the purple lights I've seen have been of the same design, and they seem to be in towns that are (at least to some degree) cash-strapped. The manufacturer better be replacing these under warranty. There aren't any of them in my town, though I've seen one LED streetlight so far that went out. The main streets have lights with a slight yellow tint, and the side streets are neutral white, which I find much more pleasing than the purplish mercury arcs they replaced.
- chasil 1y ago"LED Filaments" are a more direct example of phosphor-coated blue. Most everyone has seen these now, in "Edison Bulbs" or elsewhere. https://en.wikipedia.org/wiki/LED_filament https://en.wikipedia.org/wiki/LED_filament
- relwin 1y agoMy LCD TV did the same thing with a few of the backlight LEDs. Makes a big purplish splotch on the screen. Replaced the backlight strips and took the lens off of one of them and was surprised how small the LED is -- tiny yellow 1.5mm squares.
- dacox 1y agoThis is happening everywhere where I live (Vancouver)
- bpye 1y agoNot just CoV either, I’ve seen them in the City of North Vancouver as well.
- neilv 1y agoAs someone who walks a lot (including, for many years, back late at night from work or school), I really wish they'd made the LED streetlights approximate the original warm color temperature from the start. Instead of going bright white, high-color-rendition, wake-up-and-kiss-your-sleep-schedule-goodbye, which is what they went with instead. When the LED streetlights were first installed, they were horrible, and we were promised they would be adjusted, but they never were sufficiently. Maybe caring about the look of neighborhoods, and the sleep of people who walk or have unfortunate bedroom window positions, would've had a side effect of avoiding the problem in the article?
- hollerith 1y agoI've started wearing blue blockers when going out at night.
- neilv 1y agoWhich is why this part of the article was the frustrating icing on top: > One thing that Bullough suggests pedestrians and drivers do to stay safe under purple streetlights—or any lights, for that matter—is to remove sunglasses and blue-light-filtering glasses when walking or driving at night.
- Zak 1y agoThere are 1800K white LEDs as well as phosphor-converted amber made to approximate the look of the classic amber low-pressure sodium. 1800K white can render colors surprisingly well depending on the phosphor mix. I recently put one with claimed (and measured) CRI over 90 into a flashlight and was surprised to see that it actually can render blues reasonably well. I'm inclined to think those are better choices for street lights than anything daylight-ish, but I also think we should use far fewer street lights. Their presence often reduces the contrast car headlights provide, making it harder to spot hazards while driving.
- cootsnuck 1y agoThere's multiple adjacent parking lots in my city that are full of street lights that emit blue light. I've been wondering for awhile why in the world they would be blue but I think I got my answer. Probably someone trying to cut costs a bit too aggressively. My city and state are known for skimping on anything and everything when it comes to streets and roads.
- bertm 1y agoA friend and I found a contractor to give us a couple of these lights in the Phoenix area. We traced the LEDs back to a Seoul Semiconductor Phosphor on-chip design. We still have a suspicion that LM80 testing didn’t catch this and it was due to a thermal cycling failure. https://m.youtube.com/watch?v=4Mll-YDDAF4 https://m.youtube.com/watch?v=4Mll-YDDAF4
- worik 1y agoWow! The comments here! Are we really such neo-phobe curmudgeons? Sodium hallide street lights preferred over LEDs? Golly Hacker News, get a grip and join the modern world!
- harimau777 1y agoWe live in a late stage capitalist society. Anything new is almost always engineered to be lower quality in order to cut costs and extract more money from us.
- rco8786 1y agoAn apartment building a few blocks over from me has these. It makes the whole area look like a night club. Very weird.
- keepamovin 1y agoTrade-off-aware software engineers discussing streetlight variant choices is the infinite loop of endless discussion.
- rtkwe 1y agoWe had some of these on my street. Honestly liked them better than the full power ones they got replaced with.
- hackernoops 1y agoGlad I converted nearly all of the lights in my house to halogen, and stocked up on decades of bulbs, before the ban. Nice warm adjustable light. No strobing LED trash fucking up my eyesight.
- dtgriscom 1y agoI'm the opposite; glad to have all LEDs. Cool, dimmable, and energy efficient.
- frosted-flakes 1y agoIncandescent lights are still widely available if you still want them. Nonetheless, modern high quality LED lights can actually exceed the colour rendering index of incandescent lights, though they tend to be a little more expensive. I don't think it's a big deal to pay $15 for a bulb that will still be there in 15 years.
- userbinator 1y agoI find it somewhat amusing that they had to find "scientists" to explain this, when the purple tinge is something that LED TV repairmen have been dealing with for around a decade now. However, they're correct that it's because the phosphor layer is getting damaged, probably because they're being driven too hard by the LEDs, which are now being optimised for brightness and recurring revenue instead of longevity and efficiency. Also, I personally think spirited driving on a purple-lit nearly empty highway at night is a uniquely fun experience with an 80s-retro-futuristic vibe. The streetlights are merely accent lighting at that point; the highbeams are for actual visibility.
- jcrawfordor 1y agoI wrote an article about this almost a year and a half ago, and I was wondering how it's held up. I think Scientific American is remiss in not digging a bit deeper, because to me one of the main parts of this story is a commercial phenomenon - street lighting in the US is pretty monopolized, almost all municipal street lights and a good portion of area lights are made by the same company (Acuity). That makes it a lot less surprising that they would exhibit a similar failure around the same time. Acuity has acknowledged a phosphor defect in their lights and had launched a major warranty repair campaign, but I'm not sure how well that's gone given that new failures are still occurring. At least a year ago, they were struggling with the scale of the problem: it just takes a long time to schedule replacement of failed fixtures when there are so many of them.
- kuon 1y agoIt is not directly related to the article, but the decaying LEDs mentionned in the article made me think of it. Since we had to switch to LEDs, I had to change lightbulbs waaay more often. I realize they consume less (even if here they would just help heat the house so the energy is not lost), but hell they are crap. They start blinking, their color is shifting, they die quickly, they are super expensive, they are bigger and many lamp I had couldn't be fitted with LEDs unless I found some smaller ones which are even more expensive. This is my personal anecdotal experience, but I would be interested if any serious study had looked into this kind of issues.
- userbinator 1y agoPhoebus Cartel 2.0
- aitchnyu 1y agoSeems the elements are warrantied for 10000 hours but the drivers are not.
- mcv 1y agoGood leds are extremely durable and should last far longer than anything else, but it seems like there are also a lot of crappy leds on the market. But it's also important that leds receive the right amount of power. If they receive too much, they'll burn out. We've had this issue with a system where you clip little lights on a rail. It uses GU10 spots which exist in led, so thinking that was compatible, I used leds of course. But our spots kept burning out at an alarming rate. Turns out we need a different transformer for leds. I'm using halogen now, and it works fine.
- adrian_b 1y agoThere are plenty of cheap LED lamps with inadequate cooling or other bad components, which will become defective after a relatively short time. I have switched all the lighting in 2 apartments to LED lamps, more than 10 years ago, and no lamp has gone defective until now. However, they were Philips lamps and not one of their cheapest models, but some model with 1521 lumen @ 13 W and 4000 K color temperature, i.e. slightly more luminous than the classic 100 W incandescent lamps and with almost white light, only very slightly yellowish, very unlike the yellow lamps with a color temperature under 3000 K, and also very unlike the cheap bluish lamps with a 6500 K color temperature. My LED lamps are screwed in traditional incandescent lamp fixtures, which hang from the ceiling, but unlike some bad lamp fixtures, mine have below them a diffusive screen, to avoid direct light, but they are completely open above, so they do not impede cooling.
- wkat4242 1y agoEven the streetlights protest the anti-LGBT narrative in the US :)
- JHONWALTER 1y ago[dead]
- owenversteeg 1y agoI have to say I'm disappointed in the level of discussion on this subject (elsewhere online and here on HN.) It is obvious to anyone who has ever paid attention to an LED that this is a failure of the phosphor adhesion; more specifically, the phosphor (a fine powder which converts the nearly monochromatic blue-purple LED light to the broader white) is held in silicone, in a small dab on the surface of the LED. The fact that this silicone lasted only a few years is the surprising part; sure, the environment inside the streetlights is harsh (large temperature and humidity swings) but a high-quality silicone should be able to handle this for significantly longer. It would be nice to read some discussion of the core issue - the silicone - to me, it seems like a total failure of the silicone and not just an adhesion issue, as the photos seem to demonstrate small cracks leading to larger cracks and then total failure. Perhaps related to the addition of something new to the phosphor mix, which might change its properties under thermal cycling? Poorly mixed silicone? Unsteady temps as the silicone was applied?