The present-day I‑10 alignment along the Santa Cruz River was laid out after a city bond issue passed in 1948 to build a riverbank-side boulevard with room for a four-lane freeway in the median to follow. The route was originally called the Tucson Limited Access Highway and the Tucson Freeway. Construction on the bypass began on December 27, 1950. The first section of bypass artery, from Congress Street north to Miracle Mile West, was opened on December 20, 1951 but had no overpasses or interchanges at Grant Road (then DeMoss-Petrie Road), Speedway Boulevard or St. Mary's Road. It was first signed SR 84A. The remainder of the route was finished by 1956 to a new cloverleaf interchange at Sixth Avenue (then US 80 and US 89). In 1958, the state added the bypass to the Interstate Highway System as part of I-10 and began converting it to full freeway standards. The freeway was finally completed in 1961, and parts of it obliterated the original road. The SR 84A designation was entirely concurrent with I-10 between Sixth Avenue and Miracle Mile until October 11, 1963, when the designation was finally retired in favor of I-10.