Directly east of the town of Superior is the Queen Creek Canyon (named for Queen Creek, shown in blue, which flows through it). US 60 was built through the canyon in 1926 (this alignment is shown above in orange), and required the building of a small bridge to span the creek, as well as a tunnel. The "Claypool Tunnel" is shown above as an orange dotted line.
The current alignment (shown above in green) was built in 1952. Due to the more
advanced techniques available at the time, it followed a different alignment,
and did not require switchbacks. It still required a bridge (this newer bridge
is made of steel, as compared to the old concrete bridge), and a tunnel (the
Queen Creek Tunnel, shown as a green dotted line).
Photo courtesy of the
U.S. Geological Survey.