Surprisingly, there is a whole slew of exempt special-purpose bulbs that will continue to be manufactured, according to the Energy Department. Here’s what manufacturers can still build and stores can continue selling:
Appliance lamps, including fridge and oven lights
Black lights
Bug lamps
Colored lamps
Infrared lamps
Left-handed thread lamps
Plant lights
Floodlights
Reflector lamps
Showcase lamps
Traffic signals
Some other specialty lights, including marine lamps and some odd-sized bulbs
They got a bad rap up here in the North where we get snow. Blowing snow would often coat the lenses of traffic signals. Incandescents generated enough heat to just melt the snow, but LED replacement lamps would not and people could no longer see some of the signals. They now have thermostat-controlled heaters to solve the problem, but it made many cities gunshy.
I also live somewhere with a lot of snow and cold winters and yeah, the first ones that went in had issues with snow but now they all have heaters built in. That's why I really don't see the point of incandescent street lights now days.
People that write specs for government are quite conservative (not politically, necessarily, but more slow to change). That and the early issues with them is plenty to keep some cities specifying incandescent bulbs.
The only time I've seen that happen is when they used the full-circle hoods. Almost every one I've seen has a cutout at the bottom to prevent snow from accumulating.
They probably have heaters too though. I am not a traffic signal engineer.
Judging by the exemption list, the ban is basically just for regular household lightbulbs. Headlights are halogens, not incandescent, and the rest are speciality bulbs - though if it's legal, swapping all of those to LEDs is a pretty good upgrade.
Stock up for what? Even if they were banned, there would be LED replacements available, I'm sure. Usually parts like that have enough compatibility between models to make it worth a production run.