Why streetlights on Milwaukee interstates, highways are purple

Some Milwaukee drivers have noticed that streetlights along the interstate have recently taken on a distinctive purple hue.

It's not on purpose — a technical issue caused the 3-year-old LED lights to change colors. 

The state Department of Transportation installed a batch of LED lights in 2018 as part of a wide-scale conversion of Milwaukee's streetlights led by the Department of Public Works in an effort to save energy costs. 

In March, hundreds of the lights — mostly in the southeast region — began changing color from white to purple because of a technical glitch in the bulb. 

Michael Pyritz, regional communications manager for the DOT's southeast region, said the manufacturer who supplied the lights, American Electric Lighting, will be replacing the lights and compensating the department. 

"We are not going to a purple-hued street lighting plan," Pyritz said. "I didn't imagine that anybody was going to become that attached to them."

The replacement lights will again be bright white to "safely light our interstate system," he said. 

Pyritz said the department estimates around 300 lights have changed color.

Many communities around the country are experiencing the purple light effect, including Eau Claire and cities in Kansas, South Carolina, Illinois and Florida. 

Duke Energy, which installed the lights in some other regions, said there are likely thousands of LED lights installed throughout the country that will turn purple.

Reporter Grace McDermott contributed to this article.

Contact Drake Bentley at (414) 391-5647 or DBentley1@gannett.com. Follow him on Twitter at @DrakeBentleyMJS