Some say they’re blue. For others, they’re purple. Either way, dozens of coloured lights are illuminating parts of Deerfoot Trail and Stoney Trail— leaving many Calgarians wondering why.
The province has confirmed that, contrary to many theories, the lights aren’t intentionally blue. In fact, it’s the result of a manufacturing defect affecting one to two per cent of LED bulbs which was installed seven years ago.
According to Alberta Transportation and Economic Corridors, 70 of 7,000 street lights along those two provincially-maintained routes have turned blue or purple.
A provincial spokesperson said, the issue of LED lights turning blue appears to be the premature delaminating of the phosphor coating on the light. Lights are being replaced as they burn out, but at this moment there are no plans to replace the blue lights.
Meanwhile, some Calgarians say they’re worried about potential safety implications if individuals are driving through dimmer lights at night.
The blue glow has been seen in many cities across the world. Governments in Vancouver, Winnipeg and Kitchener worked to actively replace the defective bulbs. They’ve also become a problem in cities all over the United States, and even as far as Europe.
Associate professor of the Kartikeya Murari electrical and biomedical engineering at the University of Calgary said that, white LED bulbs naturally emit a strong blue or purple light — but that kind is absorbed by a phosphor coating, and then transmitted as a variety of green-red wavelengths, which allows people to interpret the light as white instead.
According to Murari, in these LEDs, what’s happening is that the phosphor is coming off and as a result, you’re able to see those blue or purple kind of wavelengths more.
As for why the phosphor coating is delaminating early, Murari said it’s hard to find out without examining the bulbs in a lab. But he said he suspects heat plays a role — mainly in Calgary, where temperatures vary significantly.
Murari says that, yet there are many unanswered questions about how the lights affect visibility, or even health, but he does know one thing: “We don’t see quite well in blue light, and that can be a concern.”
From the City of Calgary, a spokesperson said that, it doesn’t have any inventory with this defect.
While some Calgarians may not mind the moody ambiance while they drive down the freeway at night, but Lori Allan said she’s worried about safety.
About a year ago, she first started noticing the blue glow along the ring road and she said she’s been spotting them more often.
Since 2017, Allan, who’s had five grand mal seizures said the lights trigger her epilepsy.
“While we travel through the blue lights, I like to keep my eyes closed because I’m afraid that it’s going to give me a seizure,” said Allan.
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She doesn’t drive, but she is very concerned about visibility issues for others. They need to do a proper study to find out if it’s safe or not because I actually think they’re more of a hazard,” she said. “It makes it really difficult to even see the road.” The province said it’s not aware of any safety concerns, and it will monitor the situation continuously in North America and overseas.
