Good to see Washaw posting pictures again - I was wondering what happened to you.
This back access road is supposed to be for the bus tours and zoo staff only, but both times I was there this summer I kept seeing stupid visitors walking along there because they obviously don't know how to read the huge STOP sign that says buses only - no pedestrians. (Or maybe they intentionally ignored it because the jaguar and/or lion was sitting by the back fence and they wanted to get a closer look).