[hristov]

You can use a regular resistive heating coil. You can design a heating coil that will never burn out. LEDs themselves can last over 10 years. Thus the combination of led plus heating coil will last you more than ten years. Incadescents on the other hand burn out all the time especially when they need to be turned on and off very often, as in traffic lights. For an American city the upkeep of traffic lights is more expensive than the hardware. Also traffic lights that burn out will cause dangerous co fictions and may cause accidents.