I have no first hand knowledge.  But several months ago I drove on route 61 between 222 and 78 and saw at least 3 or 4 AMPs in that one stretch.  I couldn't find any mention anywhere, I didn't have time to explore and haven't been back since.  But from a passing glance they looked like the kind of AMPs you used to find along or near 611, and those were always FS.