This is a red equipment ground beside the red ungrounded conductors and the white ungrounded conductors, the switches supply 240v sportslighter fixtures on the pole. The installation is EMT conduit with 10/2WGUF supplying the switches. I don't use conduit in lieu of a ground but if you only had red on the truck and did not want to get the green wire it might be a good time just this once to use the EMT as a ground.
I think these guys must have been color blind, or maybe totally blind and the braile dots were worn off of the wire reels. It could be that if you pay attention to these minor details you can't make a profit on your quality work.