Planning for the Elvas Freeway commenced in 1947. The route north from C and 29th/30th Street to Arden Way and Swanston Road in Sacramento was approved by the California Highway Commission in 1949. Construction on the bridges across the American River started in May 1950, but halted in 1951 due to steel shortages. Succeeding work on the 2.9 mile long highway resumed in 1952 and the Elvas Freeway opened to traffic on May 12, 1955.4
Interstate 305 was created in May 1980 by an action of the FHWA, after the long-planned upgrade of the Capital City Freeway (Business Loop I-80) was canceled.1 This upgrade outlined a new freeway to replace the Elvas Freeway north across the American River at Arden Fair to former I-880 at Watt Avenue. The realignment of I-80 would remove substandard sections of freeway, including some sharp curves, poor sight distance, narrow right-of-way, and small or nonexistent shoulders. The plan was moving forward through the 1970s until 1979, when the Sacramento City Council voted that year to delete the new Interstate 80 alignment and use the funding and right-of-way for a rail transit system. As a result of this action, the acquired right-of-way intended for I-80 and the partially built roadway was converted into a parking lot for Sacramento’s light rail system.
Subsequent actions by the State of California and the FHWA rerouted Interstate 80 onto the existing Interstate-standard Sacramento Bypass (then known as Interstate 880). The unbuilt portion of I-80 in Sacramento was formally withdrawn from the Interstate System on May 15, 1980.2 The Elvas Freeway was renumbered as California State Route 51, but it was signed as part of Business Loop I-80 (Capital City Freeway) to allow for clear direction for travelers along Interstate 80 into Downtown Sacramento.
Interstate 305 (FAI 305) was established between I-80 in West Sacramento and U.S. 50 and SR 99 in Sacramento formally by the American Association of State Highway and Transportation Officials (AASHTO) on November 14, 1980. This included extending U.S. 50 west from SR 99 to I-80 over the 29/30th Street Freeway and the W-X Freeway. I-80 and I-880 remained in their previous, California-legislatively defined alignments in the state highway system until 1982.
California State Senate Bill 191 in 1981 made several changes in the highway system to reflect the FHWA and AASHTO actions. The SB 191 legislation deleted Interstate 880 from the state highway system and rerouted Interstate 80 over it. The FAP 51 segment of the Elvas Freeway was renumbered as SR 51. SB 191 did not call for the creation of Interstate 305 as a state route; instead it outlined the westward extension of U.S. 50 to I-80 in West Sacramento.
SB 191 established Business Loop I-80 along both the U.S. 50 extension west along the W-X Freeway (FAI 305) and the Elvas Freeway (SR 51) northeast from SR 99. Caltrans references the FAI 305 section a Legislative Route Route (LRN) 50.
Business Loop I-80 was renamed as the Capital City Freeway by the Sacramento Area Council of Governments (SACOG) in 1996. Despite the change, motorist confusion remained an issue and in 2015 sign changes implemented along the U.S. 50 portion of the route de-emphasized the Business Route.