I think it may be, notice how the Opticom receiver wire goes into the cobra! I'm sure it then just goes into the mast arm but it still looks very strange.
Here it was installed in this location because of a bridge. (see street view) It also seems to have its original lens broken in the street view so it must of got this one not too long after.
I thought it was on a tapered E arm before I opened the streetview.