August 15, 2009 Since we arrived at Zion National Park, Utah via the East Entrance, we needed a special pass to go through the Long Tunnel.
"Vehicles sized 7'10'' in width or 11'4'' in height, or larger, are required to have an ''escort'' (traffic control) through the Zion-Mt. Carmel Tunnel. Vehicles this size are too large to stay in their lane while traveling through the tunnel. Nearly all RV's, buses, trailers, 5th wheels, and some camper shells will require an escort."
The "escort" fee is $15, but the drive is escort-less, 1.1 miles of dark and little forgiveness. The bus is about 12'8" tall. The max height allowed is 13'1". Inches either way = damage. We straddled the centre line and crept through the mountain.
P.S. - The South Entrance offers no such excitement.