Interstate 10 in Arizona 2013. The remainder of the old US 80 section was rebuilt to interstate standards, with completion in 2014. East of Tucson, I‑10 parallels and in some cases overlies old US 80 to Benson, and was originally co-signed as US 80 and SR 86. The section of I-10 from Valencia Road to Rita Road was the first construction project in the state of Arizona funded by the Federal Aid Highway Act of 1956. Construction began in 1957 and was completed in 1960. From Benson, the Interstate follows the Southern Pacific mainline east through Willcox and Bowie to New Mexico, rather than
Arizona State Route 75 with US 666 was transferred to US 666. Arizona State Route 75 State Route 75 (or SR 75) is a state highway in eastern Arizona that stretches from its junction with U.S. Route 191 and State Route 78 near Greenlee County Airport south to its junction with U.S. Route 70 in Duncan. It is primarily a shortcut for north and southbound traffic between Duncan and Clifton. The southern terminus of SR 75 is located at a junction with US 70 in Duncan. It initially heads northeast from this intersection but curves back towards the northwest. As it continues towards the