Why are some of Juneau’s street lights glowing purple?

Some Juneau residents have noticed street lights with a purple glow popping up around town. A KTOO listener asked why.

A street light near the Juneau Public Library glows purple on Sunday, Jan. 23, 2022. (Photo by Bridget Dowd/KTOO)
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On a foggy Sunday night in Juneau, the corner of Ferry Way and Marine Way is made eerie by a violet glow coming from a nearby street light. It’s just one of several lights around town that have changed colors.

A Curious Juneau listener saw these lights around the city and asked KTOO why the lights have a dark purple hue. As it turns out, the color is a mistake and the state is working to fix it. 

 Juneau resident Max Stanley said he and his girlfriend noticed the lights in October when they were driving toward Thane.

“At first we wondered if it’s something for Halloween,” Stanley said. “As we continued to drive, we realized it’s just — all the street lights have this hue.”

Stanley said over the next few weeks, they noticed the same purple hue coming from several other street lights all over town.

“It’s pretty noticeable sometimes when there’s one of the purple ones and then right after an older white one,” Stanley said. “So we just were wondering why there are these new purple-hued lights around town.”

The Alaska Department of Transportation and Public Facilities maintains a lot of Juneau’s street lights. Spokesperson Sam Dapcevich said the lights actually aren’t new at all and the purple hue isn’t intentional.

“The purple hue in the LED lights is caused by a computer chip issue, possibly a defect,” Dapcevich said.

The department is working with the manufacturer, American Electric Lighting, to get the lights fixed and Juneau isn’t the only place where the issue has been reported.

“It was occurring in quite a few places around the country,” Dapcevich said. “It appears that most of the LED street lights have three colors. They have yellow, red and blue and the yellow color is failing.”

Of course, when red and blue mix, the resulting color is purple. Dapcevich said most of the lights are less than 5 years old. They’re still under warranty, so the manufacturer should cover the cost of fixing them as well – though he didn’t have an answer as to when that would happen.