I will try to grab a pic. They are every ten miles out here in Venango County. They appear to have 3 microwave type antennas on them. I also have seen them on I79
Without seeing them, it is hard to answer your question. They could be microcell fill in sites for the STARNet system. There are only 736 of them in service around the state.
Sorry, to open an old thread, but I have been seeing these as well. They aren’t always at an interchange, but seem to be every few miles in some places. I took a photo of one the other day. Any ideas?