Photos: Flickr, CC (one & two)
Nothing We Can't Fix
LED traffic lights have many advantages over incandescent technology: They last a lot longer and require less maintenance, they use a fraction of the electricity, reducing the city's power bills, and they are arguably easier to see (at least that has been my experience). But their high energy efficiency can go from upside to downside during certain types of snow storms; if snow somehow ends up covering the lights (heavy sticky snow being blown sideway by heavy wind, for example), LEDs don't emit enough heat to melt it down.Here's a video from a local station in Wisconsin about the problems they've had with their LED traffic lights (1 crash apparently caused by it):
Let's Keep Things in Perspective
In the news segment above, they mention at the end that it was the first time in 7 years that the city had to send crews to clear the snow from the LED traffic lights, so it takes a very special kind of snow storm to cover the lights. Where I live in Canada we've had these LED traffic lights for a few years, and I've never noticed one that was obstructed by snow (though that's just personal anecdote, so take it for what it's worth).
Some Ideas on How to Solve that Problem
Some have suggested adding small wipers to the lights, but I don't think that's the best way to do it. Wipers would require maintenance because of the moving parts, and they probably won't work very well with certain types of snows and ice.
Some companies apparently sell heated light covers, but if they are heated at all times, this extra energy drain could significantly reduce the savings of LEDs over incandescents.
The best way that I can think of is to have some type of optical sensor in the light that detects when something is obstructing the light. When the sensor detects this, a small electric heater would be activated to melt the snow or ice. This seems like the best way to balance power savings, low maintenance (no moving parts), and safety.
Via Wisconsin State Journal, Fox6Now
More on LED Lights
Osram Life-Cycle Analysis Finds Manufacturing of LED Bulbs Not That Energy-Intensive
Straight from the Future: 3.5 Watts Prototype OLED Desk Lamp from Project TOPLESS