Several LED street light bulbs have turned purple in my area, and people seem to either love it, or hate it. Other cities have had the same phenomenon, and the explanation is a defect in the bulb’s coating. Some places are working to replace them, and others aren’t doing so as aggressively.
Here’s the story from my area; there’s actually another story from April, but it’s basically clickbait so I won’t post that link.
And this one is from the CBC, specifically about Vancouver, BC
When I saw the post title I was thinking this would be in the Minneapolis area.
Interesting. We have those lights all over town, and I hate them. I just assumed it was some new fad the city traffic engineers decided to follow, for safety reasons or whatever. Good to know it’s a defect and they will (hopefully, eventually) be replaced.
They are, however, supposed to be bluer than the old streetlamps, as we can see further with less light in the bluer spectrum.
But violet is going too far for that.
My wife pointed them out here in NC last winter.
That’s why lights along airport runways are blue.
And of course, there are some conspiracy theorists who are taking this and running with it.
Actually no.
Runway edge and centerline lights are a light amber. Although the new LED ones are a brighter pure white with a slight blue-ish cast. The fixtures also have lenses to focus most of the illumination in a narrow ~20 degree cone along the runway’s axes; they’re much, much dimmer when viewed from off-axis.
Taxiway edge lights are blue. And omnidirectional. And not nearly as bright as runway lights. They’re obvious up close while taxiing, but are hard to see from even half a mile away as one approaches the runway. This is by dy design, so the maze of taxiways more or less blends into the darkness and the light amber-outlined runway stands out.
I’ve seen them in the Houston area, Dallas area, and oddly enough, in a couple of towns between Houston and Dallas. In every case, it wasn’t a consistent thing- like one light out of ten might be purple, or there might be a stretch of purple lights inbetween normal colored ones.
Just like you’d expect defective lights to be installed as replacements, now that you point that out.
I’d love to know the mechanism behind this failure, since the phosphor in LED lamps is a very well-developed technology. I have white LEDs that are approaching 100,000 hours of operation with no sign of degradation.
Poking around on google, it looks like it was one particular batch of the lights that was manufactured in 2018 that has the issue. So it’s a manufacturing issue and not a design issue. The laminate that converts the violet light into white light is defective in this batch, and degrades quickly over time. The lamps become more and more violet as the laminate degrades and peels off.
I couldn’t find any details about exactly what was done wrong in the production of this batch’s laminate.
Saw this last night on Tatum near Cave Creek:
I mean, if THAT doesn’t prove the world is flat - then what would?
did you money go to the CHEAPEST offer? … that might explain a bit … 
Huh! We have one round-about in the next county over that I know of that has street lights that were blue a couple months ago. I wonder if they’re from the same defective batch. I should get over there one evening this week and see if they’ve gotten more purpley.
I can’t tell Son-of-a-wrek. He going crazy right now because there’s a stretch of highway here where 80% of the houses have blue porch lights.
He can’t figure it out.
Support for the police, perhaps?
Actually from outer space the pattern of purple leading lights points to Mar-a-Lago, so that aliens can find and kiss the hand of the Emporer of Planet Earth.
Something interesting I have noticed the last couple days. I’m driving to work just about the time the sun is coming up. The weather’s been overcast/rainy/foggy. It’s light enough that all the regular street lights are off, but the purple ones are still lit. Does the purple light somehow affect the sensors that turn the streetlights on and off?
I happened to have my DSLR with a 400mm lens last night when I stopped for groceries, and saw a purple streetlight. Here is what the array looks like:
So, the explanation that it’s some sort of filter separate from the LEDs is bunk.
There’s a gas station/convenience store chain around here called Sheetz, and in many of their stores they’ve installed blue lights in the restrooms to discourage intravenous drug use (it’s difficult if not impossible to find a vein in blue light).
When I saw blue/purple streetlights I assumed they were for the same reason (truckers often stop and rest on the highway shoulder under the lights), then I read about the manufacturing defect when I looked it up out of curiosity.
