LED traffic lights save vast amounts of energy over traditional installations and last far longer. However, the lower energy use of these Light Emitting Diodes translates into decreased heat output. In northerly climates, when snow storms dust the lights, there is sometimes not enough heat to melt it off, and the traffic lights are rendered useless. (See story here.)
There is ample heat given off by the circuitry behind the light, but very little by the light itself. One solution could be to connect a metal conduit that leads from the circuitry in the back to a wire/mesh grid embedded in the front lens or simply layered on top of it. This would be similar to the rear-defrost technology that most cars have.
IDEATION: November 1, 2009.