https://www.nps.gov/blri/planyourvisit/tunnel-heights.htmThe heights on this chart are the very edge, off the road and into the shoulder, and the center of the tunnel.
I have driven the Skyline and Blur Ridge Parkway many times; it is one of my favorite drives. Unless your RV is over 13" tall, you will have no problem with ANY of the tunnels. The tunnels are curved archway, so the confusion starts when the Park Service lists the clearance at the edge of the tunnel instead if the actual driving lanes. You may have to hug the center line, or partially straddle it, but you will not crash into the ceiling unless you drive off the road!
