Going green has caused some Philadelphians, including City Councilman Frank Rizzo, to see white.
"The new LED traffic-bulb lights were completely coated by snow and ice, preventing drivers from seeing the signal," Rizzo said about his commute to work Thursday.
Although energy-efficient and cost-effective, LED lights have a downside. The LED bulbs burn cooler than the old incandescent lights, meaning snow that covers them melts more slowly, said Mark McDonald, Mayor Nutter's spokesman.
There weren't any reports of accidents because of the snow-covered lights during this week's storm, said Philadelphia police Cpl. Jeff Smith, of the Accident Investigation District.
However, snow-covered LED traffic bulbs were blamed for numerous collisions and a fatal accident in Oswego, Ill., in April 2009.
In 1998, Philadelphia began installing red LED bulbs on traffic lights, and started replacing the green and yellow bulbs last June.
McDonald said the city has saved $8.4 million in the past decade. He said the city plans to save up to $1 million a year in energy costs by switching to all LED.
"I prefer to make sure public safety is the most important issue," Rizzo said. "Energy conservation is a nice thing, but we can't have our traffic lights looking like someone hit them with a snowblower."
Other cities that are prospering with LED traffic lights have adapted to some of the new technology's imperfections.
In Milwaukee, the city purchased long poles and brushes to manually clean the lights, according to the city's chief traffic and street-lighting engineer, Bob Bryson. Cops and snow-removal trucks report covered lights.
In Denver, workers use air compressors and long brushes to clear snow-covered traffic lights. Denver also monitors most of its lights from a traffic-control room.
McDonald said drivers in Philadelphia should call the city's 3-1-1 nonemergency hot line if a light is covered and "proceed with caution and care."