As defined in the California State Highway Code, legislative Route 51 is to be signed and designated as "Interstate Business Loop 80." SR 51 overlays the business route from the junction with U.S. 50 and SR 99 northeast to the interchange with Interstate 80 and SR 244 (Auburn Boulevard) along the Elvas Freeway. The portion of Business Loop I-80 along SR 51 is locally referred to as the "Capital City Freeway," "Cap City Freeway," "Business 80," or "Biz 80." The western section of Business Loop I-80 to West Sacramento is designated and sign as U.S. 50
SR 51 arose from the 1980 decision to cancel a planned realignment of Interstate 80 from south of the American River through northeast Sacramento, and the subsequent withdraw of I-80 from the Elvas Freeway northeast from U.S. 50 and SR 99 near Downtown Sacramento. The new alignment would have bypassed a substandard section of the Business Loop I-80 freeway north from the American River to I-880 west and SR 244 outside northeast Sacramento. The American Association of State Highway and Transportation Officials (AASHTO) approved the renumbering of I-80 between West Sacramento and SR 99 in Sacramento as Interstate 305 as well as a western extension of U.S. 50 from SR 99 to I-80 at West Sacramento on November 14, 1980. State Highway changes took place with the passage of State Senate Bill 191 in 1981. The former route of I-80 east of SR 99 to SR 244 was reclassified as FAP Route 51. The portion of former Interstate 80 between the junction of I-80/880 in West Sacramento to SR 99 was reclassified as FAI 305. The routes affected by SB 191, including the new Business Loop I-80, were completely resigned by 1982.
The September 2015 Caltrans signage project proposed to remove most references to Business Loop I-80 along its concurrency with U.S. 50 between West Sacramento and Downtown Sacramento. The proposal did not include options to sign SR 51.1
- "District 3/Sacramento - Sign Replacement Project" online posting by myosh_tino, AARoads Forum, September 21, 2015.
Page Updated 06-20-2018.