Interstate 780

Route description

The entirety of I-780 is defined in section 623 of the California Streets and Highways Code as Route 780, and that the highway is from "Route 680 at Benicia to Route 80 in Vallejo". This definition roughly corresponds with the Federal Highway Administration (FHWA)'s route logs of I-780.

The I-780 state-maintained freeway actually begins at Lemon Street and Curtola Parkway, quickly crossing underneath I-80 at a cloverleaf interchange. The freeway passes through parts of unincorporated Solano County, then heads southeast along the Benicia State Recreation Area (a marsh). It then bypasses downtown Benicia through the hills to the north. I-780 ends at I-680 at the north end of the Benicia–Martinez Bridge, with I-680 heading south through the East Bay to San Jose.

I-780 is part of the California Freeway and Expressway System and, as with every Interstate Highway, is part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration (FHWA).

History

By 1914, a paved county road connected Vallejo and Benicia north of the Carquinez Strait, following the present Maine Street, Benicia Road, Columbus Parkway, and K Street. Although state highways were designated to Benicia in 1910 (Legislative Route (LRN) 7, now I-680) and Vallejo in 1931 (LRN 74, now SR 29), this connection was not added until 1935, when LRN 74 (an unsigned designation) was extended east from Vallejo to Benicia and north along former LRN 7 to Fairfield. (A short spur connecting Vallejo to the Carquinez Bridge was added to LRN 74 in 1937.) LRN 74 initially entered Benicia on K Street and left on East 5th Street, making several turns in between. Two realignments were built in the 1940s, reducing the number of turns to one, at the corner of L and East 2nd streets.

On September 15, 1955, the Bureau of Public Roads approved the Interstate Highway System spurs and connections in urban areas. Among these was a loop around the San Francisco Bay, soon numbered I-280 and I-680. The east half (I-680) incorporated a number of existing legislative routes, including LRN 69, LRN 108, LRN 107, LRN 75, and LRN 74, crossing the Carquinez Strait on the proposed Benicia–Martinez Bridge and ending at I-80 near downtown Vallejo. The first piece of this freeway north of the Carquinez Strait was at the I-80 cloverleaf interchange, built in the late 1950s when I-80 was upgraded through Vallejo. This was an extremely short roadway, beginning at Lemon Street, crossing under I-80 and Laurel Street and ending at Reis Avenue and Cedar Street. In about 1960, it was extended east to the old highway (Columbus Parkway) between the cities and was completed to the new bridge in about 1962, the year the bridge opened.

In the 1964 state highway renumbering, the legislative designation of the completed Vallejo–Benicia freeway was changed from LRN 74 to LRN 680, reflecting its Interstate designation. The short piece of nonfreeway in Vallejo, extending west from I-80 to SR 29, became State Route 141 (SR 141). This route followed Benicia Road and Maine Street, the same alignment the state highway had always taken; it initially connected with I-780 via Lemon Street but later followed Benicia Road from I-80 north of I-780. In 1975, a proposed (and never constructed) extension west and north to SR 37 east of the Napa River was added to LRN 141. The route was to be the Waterfront Freeway, scaled down to a boulevard in 1974.

The FHWA approved a relocation of I-680 onto the SR 21 freeway between Benicia and Fairfield in July 1973. To keep the route to Vallejo in the Interstate system, it was renumbered I-780; As part of the project to construct a new northbound Benicia–Martinez Bridge, the I-680/I-780 interchange was rebuilt; the new span opened in August 2007. LRN 141 was deleted from the state highway system in 1988, soon after the city of Vallejo constructed Curtola Parkway over (replacing Maryland Street) just to the south, directly connecting I-780 with a surface road to SR 29.

Exit list

Mileage was measured from east-to-west based on the alignment of LRN 680 as it existed at that time. Exit numbers were still assigned the conventional west-to-east ascension.

References

References

1. (December 31, 2021). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways". [[Federal Highway Administration]].
2. "Section 623". California Office of Legislative Counsel.
3. [[Google Maps]] street maps and [[USGS]] [[topographic map]]s, accessed February 2008 via [http://mapper.acme.com/ ACME Mapper] {{Webarchive. link. (January 2, 2008)
4. {{CAFESystem
5. {{FHWA NHS map
6. {{FHWA NHS
7. Grinnon, Edmund. (15 May 1914). "Road News from All Over The State". Oakland Tribune.
8. Official [[Automobile Blue Book]], [https://books.google.com/books?id=Mt0NAAAAYAAJ Volume Eight], 1917, pp. 146, 180
9. {{cite CAstat. (1935)
10. {{cite CAstat. (1937)
11. [[United States Geological Survey]], [https://web.archive.org/web/20110719150325/http://sunsite2.berkeley.edu/lizardtech/iserv/calcrgn?cat=histopo&item=brk00000052_10a.sid&wid=600&hei=500&style=generic%2Fview.xsl&plugin=true Carquinez Strait] (scale 1:62500), 1940
12. [[National Bridge Inventory]] database, 2006: the bridges on East Second Street north of Benicia are dated 1942 and 1944; the pedestrian bridge over Curtola Parkway is dated 1987
13. [[United States Geological Survey]], [https://web.archive.org/web/20110719150401/http://sunsite2.berkeley.edu/lizardtech/iserv/calcrgn?cat=histopo&item=brk00000275_10a.sid&wid=600&hei=500&style=generic%2Fview.xsl&plugin=true Benicia] (scale 1:24000), 1950
14. [[Bureau of Public Roads]], [[General Location of National System of Interstate Highways]], 1955: [[:Image:San Francisco, California 1955 Yellow Book.jpg. San Francisco]]
15. [[California Department of Transportation]], [http://www.dot.ca.gov/hq/tsip/hseb/products/state_highway_routes_selected_information_1995_revised.pdf State Highway Routes: Selected Information] {{Webarchive. link. (March 16, 2007 , 1994 with 1995 revisions, pp. 342, 348)
16. {{Caltrans bridgelog. (July 2007)
17. [[United States Geological Survey]], [https://web.archive.org/web/20110719150409/http://sunsite2.berkeley.edu/lizardtech/iserv/calcrgn?cat=histopo&item=brk00000276_10a.sid&wid=600&hei=500&style=generic%2Fview.xsl&plugin=true Benicia] (scale 1:24000), 1959
18. {{cite CAstat. (1963)
19. [[Division of Highways (California). Division of Highways]], [http://cahighways.org/maps/1963sfbay.jpg San Francisco and Vicinity] {{Webarchive. link. (December 31, 2007 , 1963)
20. [[California Department of Transportation]], [http://cahighways.org/maps/1986sfbay.jpg San Francisco and Vicinity] {{Webarchive. link. (December 31, 2007 , 1986)
21. {{cite CAstat. (1975)
22. [[Vallejo Times Herald]], No Freeway for Waterfront Blvd, April 25, 1974
23. [[Vallejo Times Herald]], Vallejo Approves Measure to Speed Waterfront Boulevard Construction, August 20, 1974
24. the corresponding legislative changes were made in 1976.{{cite CAstat. (1976)
25. [[Metropolitan Transportation Commission (San Francisco Bay Area). Metropolitan Transportation Commission]], [http://www.mtc.ca.gov/news/press_releases/rel418.htm Rep. George Miller to Keynote Celebrations for Completion of New Benicia-Martinez Bridge]{{dead link. (January 2013, August 23, 2007)
26. {{cite CAstat. (1988)
27. {{Caltrans trucklist}}
28. (March 17, 2020). "Interstate 780 Freeway Interchanges". [[California Department of Transportation]].