I don't know if this holds true in general, but I noticed on a road trip that when we crossed from BC to Alberta, the rest areas seemed to disappear. Like in BC most roads have stops along the way with gravel parking lots, maybe a little park with an outhouse and a picnic table, or a viewpoint with some signs describing history. When we crossed into Alberta it was like the rest stops disappeared. But it might have just been the road we were taking.