Impassable Barrier

In the 1920s this end of the canyon appeared to be a dead end, an impassable barrier to transportation. Highway engineers faced their toughest challenge in the cliff above and solved it by building a one-mile tunnel behind the cliff face. When the tunnel and highway were completed in 1930, they opened the region to motor tourism, linking Zion to Bryce and the Grand Canyon's North Rim. Work began by drilling small shafts into the north-facing cliff, which later became the tunnel's four windows or galleries, providing light and air and serving as places to expel rubble as workmen tunneled toward both ends. A temporary wooden framework at the east portal was later replaced with a concrete bridge. Portions of the tunnel were shored with timbers, and in 1937 the entire tunnel was lined with concrete. The small pilot tunnel was enlarged by drilling and blasting, with crews moving forward 30 to 36 feet a day. Today the tunnel has become a kind of barrier itself, as RVs and tour buses are too large for two-way traffic within it.

Utah · United States