I was just wondering, it seemed like there was some legislation passed at some point requiring highway lighting to be the FCO (full cut off) optics? I was just wondering because it seemed like I remember hearing that. And most of the newer cobras on the highways here (installed since 2012 or so) are the FCO version. With the AEL 125 and GE M400 ones. Plus the newer streetlights and area lights that are cobras are FCO too, the AEL 125.

Yes, some areas do require FCO optics for lanterns above some light output threshold. The threshold uses to be just a bit above what the typical home use wall packs/bucket lights give off (175W probeMH/MV or 100W HPS; the intention is to address the street lights and commercial installations but do not restrict the typical home owners).
Usually where is some light sensitive facility near by (astronomical observatory, wildlife preservation) or something similar.
It is not 100% everywhere, but these areas are growing...

It's a regional thing. I think Flagstaff, AZ is one of the most outwardly dark-sky vigilant municipalities here on the mainland USA. I am actually a huge proponent of minimizing light pollution, and don't think I would be upset if moving forward we started designing lights to accommodate wildlife and skylight pollution. You also have the Big Island of Hawaii, which I have made a post or two on before, and their new approach by utilizing different color temp LED's to combat pollution. I think they are actually quite awesome, but everyone here likes to (...) on them.

I see. Well the ones I'm talking about with the FCO, were mostly installed along the highway at four way intersections. Where there used to be one semi cutoff fixture at each corner on the highway, they added about 5 FCO fixtures in all four directions. Plus closer to my house at a three way intersection, there used to be no fixtures at all, and they added about 20 FCO fixtures. These are near a state park and also a preserve, so that could have part to do with why they are FCO.

But Duke Energy mostly use the AEL FCO for area lighting probably because it would cause less nuisance for neighbors.

And I agree I think minimizing light pollution is a good thing, even if some of my favorite fixtures aren't very good at it.

With the large service providers it probably comes down to cost and efficiency. TXDOT got a huge hardy for FCO HPS fixtures within the last decade before switching over to LED. I'd like to say that the government here is trying to do right by its neighbors, both human and other, but I think they just go with whatever will save them the most in the long run. As a taxpayer, I appreciate this immensely, but think there is an ethical side to this that is sometimes ignored. Don't get me wrong, I am a pretty conservative to libertarian leaning guy, but I believe in moderation, and doing what good for everyone, not just what makes people feel good. /end political rant.

Some of my favorite fixtures are definitely not FCO, and I also understand our fanatical side as far as what most light enthusiasts consider to be best.

It's a regional thing. I think Flagstaff, AZ is one of the most outwardly dark-sky vigilant municipalities here on the mainland USA. I am actually a huge proponent of minimizing light pollution, and don't think I would be upset if moving forward we started designing lights to accommodate wildlife and skylight pollution. You also have the Big Island of Hawaii, which I have made a post or two on before, and their new approach by utilizing different color temp LED's to combat pollution. I think they are actually quite awesome, but everyone here likes to (...) on them.

As I remember Flagstaff from 15 years ago, it was to me really a LPS orange glow city.
But last year's visit was more of a mixture HPS/LED impression to me.
But I was visiting just the places surrounding the Interstate (I40, if I remember well).