But they should at least care about the supposedly certified bulbs the municipality is installing in their lights?
I’ve not seen any municipalities who had any specific requirements to install anything “certified” to anything other than NEC and maybe FCC Part 15.
Also never seen FCC go after a municipality for noisemakers unless they’re searching for a very specific interference complaint, to something licensed.
And usually they’d accept the municipality just cleaning up that one emitter, they’d never go after them for buying hundreds of the noisy things.
Really, they don’t care unless you can get a complaint from the broadcast station’s engineer about each and every traffic light that does it to their station.
The only way you’d ever see enough political impetus to take broad scale action would be if a Public Safety organization complained that the municipality was jamming their comm, and considering that department would work for the same municipality, they’d just handle it internally.
The main exception possibly being FAA or a FedGov LE system being hammered by a municipality’s poor choices/cheap choices of stop lights.
Commercial broadcast versus stop lights? It’d be very hard to get FCC field offices involved in such a thing.