The LED lights use way less power, about 10% of the old bulb lights. I think most communities switched for the cost savings. But, watch what happens, a few cities will get sued due to accidents like this one and the government will require heaters be installed in all the lights, which will end up costing more and using more power than the original bulb light.
VERY unlikely. All the heater has to do is get the temp. up to the melting point of ice. Heater plus LED should still use less energy than incandescent (not needed year around). But the real dollar saving isn't energy----it is not having to replace the bulbs as often (like 1% as often). LED's in traffic lights are STILL a good idea.
They also last much longer, requiring less labor to maintain. They also have redundancy. An LED traffic light is made up of an array of many individual LED's. If one LED fails, the light just has some dark spots. If an incandescent traffic light burns out, the whole signal fails. What's needed is an electric heater for the LED traffic lights that kicks in when temperatures get below freezing and there is snow.
The LED lights last way longer than incandescent bulbs. Ordinary ring type resistance heaters also last way longer than incandescent bulbs. The big expense being avoided here is the cost of sending out a crew to replace bulbs.