I think they may be small as I checked the waypoints & the 1 listed in OH is small on US #24 east of Ft. Wayne, IN.
I think your right. Probably just pullouts more than large rest areas. We have a few of them here in this state that are only about big enough for 5 or 6 cars and are just a pull out. Most of them have been dropping by the wayside (no pun intended).