Why some streetlights in Green Bay, Oshkosh, Wausau and Door County are purple
GREEN BAY - The odd, purple glow isn't a commentary on Wisconsin's status as a political battleground.
Nor is it an extension of Green Bay's bridge lighting program or an indication your neighbors hosted a rave.
It's also not the work of a renegade Vikings fan.
Yes, you're actually seeing some LED streetlights cast a purple light on communities in northeast and central Wisconsin.
The appearance of the light, referred to as its color temperature, can be "a little confusing or off-putting" to people, said Steve Grenier, Green Bay public works director. Grenier said residents have called the city on some occasions about the purple lights. He passes the information to Wisconsin Public Service Corp., which installs and maintains streetlights across northeastern and central Wisconsin.
Matt Cullen, WPS' spokesperson, said the utility is aware of defective LED streetlight bulbs turning purple in communities across its service area and is working to replace them.
"While the color is different, there is no threat to safety," Cullen said. "The brightness is the same (as white LED lights). They're still performing, the only difference is the color of the light, even though it might appear like someone is a Prince fan."
Not everyone immediately notices the phenomenon, though. Sometimes the lights may appear white to those directly beneath them, Grenier said. Plus, the defect that leads to the purple hue is rare: Cullen said it has occurred in less than 1% of WPS' streetlights.
Those who do notice the effect either love or loathe it.
A sampling of social media comments highlights the range of reactions: One person said the purple hue gives them headaches due to a past concussion. Another thought it some sort of black light.
Fans said it is easier on the eyes while driving or just enjoyed seeing something a little different.
If you're in the not-a-fan group, good news: You can help get the purple lights changed out. If you're in the fan group: Enjoy it while you can.
And if you just want to know why some streetlights are purple, here you go.
Why are they purple?
It's a defect in the manufacturing process that requires understanding a bit about how light-emitting diodes work.
LED bulbs can emit a variety of colors. Green Bay's bridge lights, for example, use a combination of red, blue and green LEDs to create a rainbow of colors that celebrate special days or welcome sports fans to town.
Grenier, of Green Bay Public Works, said he "learned more about LED technology than I ever cared to" after the city installed the LED systems on the Ray Nitschke and Bart Starr bridges in downtown. He now has RGB color code lists bookmarked.
Streetlight LED bulbs would normally appear a little blue, so the manufacturer coats the bulb to turn the blue light into the bright white that comes to mind when you think of an LED.
A defect in the coating is causing it to peel away on some bulbs, producing the purple hue, Cullen said.
RELATED: Cheap solar helps Wisconsin utilities speed up green energy transition as support grows
How many streetlights are impacted?
Cullen said between 300 and 400 streetlights have turned purple, less than 1% of the roughly 50,000 streetlights WPS maintains in its service area. The service area includes areas surrounding Green Bay, Oshkosh, Wausau, Stevens Point, Oconto, Marinette and parts of Door County.
WPS first started to hear reports of purple streetlights in Green Bay in December, Cullen said.
"It does catch your eye," he said. "It's a little bit different."
Is this happening anywhere else?
Very much so.
Milwaukee area motorists noticed the purple phenomenon last year along interstate highways. The Wisconsin Department of Transportation got a similar batch of LEDs that last March started to change, leading one WisDOT official to assure motorists the state was "not going to a purple-hued street lighting plan."
The phenomenon has popped up in other regions of the U.S., too. Last fall, residents of Greenville, South Carolina noticed it, while Baltimore Ravens fans might have been disappointed to learn it to be assured it wasn't for their NFL home team.
Now, it appears to be northeastern and central Wisconsin's turn.
Interestingly, the issue doesn't seem to have impacted We Energies streetlights in communities where it provides electric service, including the Appleton and Milwaukee areas. We Energies and WPS are both owned by WEC Energy Group.
Seen the (purple) light?
To report a purple light, contact Wisconsin Public Service via its website, which has a Streetlight Problem Report Page, or by calling 800-450-7260.
Before you get to reporting a purple light, you need to get one piece of information first.
Each utility pole has a tag or identification number on it. Cullen said it will be a mix of numbers and letters on a small, metal plate. The number helps crews know exactly which pole is involved, a vital tidbit when you have 50,000 streetlights to manage.
"We can start that process of having crews go out to change the fixture for a new fixture," Cullen said. He added that replacement operations are part of WPS employees' everyday work schedule.
And the fixtures remain under warranty, so WPS and its customers, should not be on the hook for purchasing extra bulbs.
Contact Jeff Bollier at (920) 431-8387 or jbollier@gannett.com. Follow him on Twitter at @JeffBollier.
This article originally appeared on Green Bay Press-Gazette: Why some streetlights are purple in Green Bay, Oshkosh, Wausau
