Between 1968 and 1975 a 5.2-mile bypass was proposed that was to straighten the alignment of I-80 and increase its capacity. The Sacramento City Council voted in September 1979 to delete the I-80 Bypass freeway from the Interstate System. In 1980 California submitted to AASHTO proposals to relocate I-80 in Sacramento onto then I-880, extend US 50 west to cover the west half of old I-80, and to assign I-305 to the west half of old I-80, and delete I-880 in the Sacramento area (the route would eventually be relocated to then SR 17 from I-280 in San Jose to I-80 in Oakland in 1982-1984). AASHTO approved these proposals. The next year, the California State Legislature extended US 50 west to cover the western half of old I-80, and the eastern half was assigned the new SR 51 number and designated as Business Loop 80. The signage change from I-880 to I-80, and the previous I-80 to Business 80 was installed in November 1983.