There are several of these on Broadway, between Pine and Thomas. The cone is attached to a scrap of recycled street sign and the sign is bolted into the sidewalk. At first I took them for art installations made from pilfered street signs. But it seems more likely that the recycled signs are covering holes that were cut in the sidewalk to make room for new parking pay stations.
Things are much simpler — more obviously explained — than I usually allow them to be.
A few parking restriction signs in the same couple of blocks have been covered over with blue panels.