WTOP out of DC has a story on the continuing replacement of traditional incandescent stoplight lights with LED lights in Maryland. That state is about 93 percent finished with the project and what makes LED stoplights attractive are their brightness and energy saving qualities.
Here's an interesting fact about LED stoplights many don't realize until they're in place. A characteristic of LEDs is the fact that they stay cool as opposed to the old incandescents which run warm. That is where the energy savings come from, cool lights do not use as much energy as warm ones. But during winter snows the cool lights do not melt the snow and ice from the stoplights as the warm ones always do, often causing backups at intersections because the lights are not visible.
Clayton has had the LED stoplights for a few years now and while at a meeting the other night, this issue was mentioned, an aspect of LEDs no one foresaw. Not a major thing because snow is not a constant in either St. Louis or Maryland but something that state should be prepared for.
Of course in the years between Clayton's lights and the new Maryland lights, some tweeking may have been done to solve this problem.