There's an installation of cobra heads, near my house that were put about 2010. The road forms a T shape and lights were installed going both ways of the T intersection as well as the street at the intersection. But what I noticed is that the lights are all flat lens FCO, except for 3 which are dropped lens. One is the first light at the south end of the installation, second is the light right at the intersection, and third is the last light on the road that makes the T.

There must be a reason for this but I'm not sure. I could see the reason for the drop lens right at the intersection because it can light the area better.

They might have 4 way refractors.

Cole, what model are the luminaires?  If they are M250R2s, they do not have 4-way drops, since GE no longer offers this option.  If they are AEL 115s, it’s possible they may have 4-ways, but 4-ways are becoming increasingly rare.  LEDs are also replacing HiD at a RAPID rate, faster than any replacement ever.  (Except maybe Incandescent to Mercury).

FCOs exist to help cut down light pollution, and Drop Lenses do help light the area better.  So, if the drop lens is not absolutely needed, FCOs are the way to go.

My utility uses Leotek GCJ, GCM, and GCL LED fixtures now, and they are quickly replacing HiDs, even those that aren’t EOL.

Hi, they are GE M-400. Around time these were installed there was another installation of Cooper OVF with FCO nearby.

In 2016 a few mile stretch of HID were changed to LED Phillips Roadfocus. But majority of highway in town use GE M-400A2 Powr/Door with some sections being AEL 125 and some Cooper OVX spot replacement.

Last month an intersection near my old elementary school with GE M-400 drop lens got changed to some LED I don't know yet. But that's the only other LED changeout I had seen.

The latest DOT HID installation I seen is town south of me got AEL 115 FCO in section of highway and an intersection last summer.

Early 2018, a section of highway got rerouted and GE M-400 FCO installed on new arms and poles.