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Take an evening drive along New Circle Road, about a mile in either direction of where it intersects with Georgetown Road, and you’ll notice some eerie purple streetlights reminiscent of a sci-fi film.
No, aliens aren’t behind the lights, and it isn’t a publicity campaign either. Rather, the lights are malfunctioning in a phenomenon occurring all over North America, which has been dubbed by the media as “The Great Purpling.”
We reached out to the Kentucky Transportation Cabinet and confirmed the purple streetlights are the result of a manufacturing defect involving their LED bulbs. Here’s what we learned.
Why are some Lexington streetlights turning purple?
This purple streetlight phenomenon is occurring across North America, including in Kansas, Utah, Texas, Florida and Canada.
The issue stems from a process called delamination.
LED lights offer a more energy-efficient and longer-lasting light source than traditional incandescent light bulbs. One drawback, however, is they do not naturally produce white light.
One way manufacturers produce this effect is to use blue-only LEDs, but coat them with a fluorescent substance called phosphor, as explained by Scientific American.
When the blue light passes through this phosphor layer, some of the blue light wavelengths are absorbed, while red and yellow ones pass through. The result is a mix of colors and what we perceive as white light.
Are these purple streetlights safe?
While the lights may be bright enough to see by, experts say purple streetlights can have some negative effects on nighttime visibility.
John Bullough, the director of the Light and Health Research Center at Mount Sinai’s Icahn School of Medicine, told the Kansas City Star when it’s only blue light, it can be harder for the human eye to distinguish detail.
It is unclear if these purple streetlights have caused traffic accidents where drivers have encountered them, but they can make it more difficult to read signs and distinguish between different colors, Bullough said.
Blue light also poses significant risks to wildlife. It disrupts circadian rhythms and sleep patterns, increases the likelihood of migratory bird collisions with structures and hurts insect populations, including pollinators.
What is Kentucky doing about the problem?
We contacted Naitore Djigbenou, executive director of the Office of Public Affairs at the Kentucky Transportation Cabinet, with questions.
Djigbenou responded with a statement that reads, in part, “Team Kentucky is committed to ensuring that our infrastructure remains both safe and reliable for all who travel through the Commonwealth. The placement of lighting along interstates and ramps is designed to enhance visibility and safety for motorists and supplements vehicle headlights.”
The official confirmed the state is using LEDs as a cost-effective measure to light roadways and KYTC is aware of some stretches in Fayette County where the detorioration has caused the purple hue.
“This issue isn’t unique to Kentucky. Similar occurrences are being reported across the nation as LED lights age or experience manufacturing defects. The Transportation Cabinet is actively monitoring this situation and working to ensure that affected lights are replaced under the manufacturer’s warranty,” Djigbenou wrote in an emailed statement to the Herald-Leader.
Do you have a question about life in Kentucky for our service journalism team? Send us an email at ask@herald-leader.com or fill out our Know Your Kentucky form.
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