Why do the street lights on West Campus emit an eerie, bluish-purple color at night?
Starting in 2021, Triangle area residents observed street lights turning from their standard yellow-white color to a purplish hue. Purple lights have been found across the East Coast and even in Canada.
“I heard that the color is meant to prevent drug use because it makes it harder to see where the veins are,” said first-year Cesar Rodas-Menendez. Others have speculated that the blue is a spirited attempt at lighting the campus in the University’s signature hue, or that the shade is wildlife-friendly.
It turns out that the unique color is merely the result of a manufacturing defect. According to Duke Energy, the company that installed the faulty bulbs, the mistake arose from a “bad batch” of LED lights from a manufacturing partner. Duke Energy has not identified the company that supplied the color-changing lights.
Inside normal bulbs, a phosphor-silicone layer adheres to LED chips, changing the color from blue to white. In defective bulbs, this layer forms cracks over time, turning the color back to blue or purple.
Like most utilities, Duke Energy adopted the 4,000 Kelvin color — similar to moonlight — as the national industry standard for safe street lights.
Some experts — including the LED Systems Reliability Consortium — believe that the defective lights could constitute a potential safety hazard and cause car accidents, suggesting that lights with blue undertones may be disorienting for drivers or lead to poorer visibility.
But others have argued that the color change does not make any practical difference in pedestrian safety. Research supported by the Illuminating Engineering Society of North America has not found any evidence of health impacts resulting from the blue light to date.
Duke Energy said it is committed to replacing as many faulty bulbs as possible. The company has asked the public to report any purple lights by calling their customer service center at 1-800-452-2777 or using their online street light repair website.
However, some local residents don’t want the lights to change, with some finding the new look to be “otherworldly” and “fantastic” for selfies. Others find the deep purple shade reminiscent of the late singer-songwriter Prince’s 1984 hit song.
“I refer to them as the Purple Rain lights,” one Durham resident said.
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