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
Interstate 10 in Arizona were laid out along railroad tracks, and US 60/US 70 was routed mostly parallel to the Santa Fe rail tracks east of Wickenburg, and the Arizona and California Railway west to Vicksburg. The two old federal routes then struck west across the desert and state line, picking up the Southern Pacific mainline at Indio, California, and I-10 overlies the old roads most of that distance. Moving east from the California line at Ehrenburg, I-10 follows the old route of US 60/US 70 for the first east from Blythe, California. In 1960, this western-most stretch of I-10 was built from near