LED lights are good for city check books but bad in snow storms. In severe weather, snow and ice can build up on the bulb making it hard to see which light is actually lit.
One woman says she knows first-hand how dangerous this can be.
At 8:30 a.m. in February 2012, Rachel Johnson was like any other busy mom
"I had to go south on Chambers to go to the doctor's office," Johnson said. "It was snowy and icy."
Snow completely covered the street lights at South Chambers Road and East Mexico Avenue in Aurora. Johnson ran a red light without realizing it, slammed into another car and totaled her brand new Crown Vicotria.
"I was pretty shocked. I've never been in an accident that bad," Johnson said. "I just kept thinking 'what did I do?' I couldn't tell that it was a red light."
Cities around the country that have installed the energy-efficient traffic lights are discovering a hazardous downside: The bulbs don't burn hot enough to melt snow and can become crusted over in a storm.
A spokeswoman for the City of Aurora says the problem only happens when snow is accompanied by high winds.
Authorities in several states are testing possible solutions, including installing weather shields, adding heating elements like those used in airport runway lights, or coating the lights with water-repellent substances.
Almost all traffic lights in Denver are LED Perimeter. Officials from both cities say if you see lights covered in snow, treat it as a four way stop and call it in so they can dispatch a technician to clear off the bulbs.
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