Not sure about this park, but elsewhere the NPS has made this distinction clear.

Death Valley's map makes clear that a high clearance crossover, high clearance 2WD or high clearance AWD vehicle is one class, and 4WD vehicles are another. See page 2:

https://www.nps.gov/deva/planyourvisit/upload/508-Backcountr...

EDIT: https://www.nps.gov/cany/planyourvisit/maps.htm has a whole lot of maps for the Canyonlands and none of them make this distinction, maybe this isn't as apparent at that park.