California 260

California 260, which is signed in its entirety as California 61, connects California 61 in Alameda with Interstate 880 in Oakland via the Webster and Posey Tubes.

California 260 is past of an unconstructed freeway alignment that would provide access from California 61, Interstate 880, and Interstate 980 to the often-proposed but never constructed Southern Crossing (a bridge planned to cross San Francisco Bay to relieve traffic on Interstate 80 - San Francisco-Oakland Bay Bridge to the north and California 92 - San Mateo Bridge to the south). Although the Southern Crossing itself is not in the state highway system as a proposed state highway, the approaches (on the west via California 230 and on the west via California 260) are. At this time, there are no active plans to build California 260 absent plans to construct the bridge across the bay, excepting the section between California 61 and Interstate 880. This section, which is signed as California 61, connects Alameda with Oakland via the Webster and Posey Tubes.

California 260 (California 61) north
As northbound California 61/260 leaves the city of Alameda (signed as California 61, but is legislatively California 260), it gains freeway characteristics as it passes under the off-ramp from southbound California 260 to Constitution Way. Photo taken 07/05/04.
Approaching the Posey Tube, which takes California 260/61 under the Oakland Inner Harbor Channel, use the left lane for downtown Oakland/Harrison Street and the right lane to Interstate 880 (Nimitz Freeway). Photo taken 07/05/04.
The Posey Tube was named for Alameda County Surveyor George Posey, who was involved in the original design and construction of the tube. Built well before the parallel Webster Tube, it was planned in stages between 1908 and 1923, with construction beginning in 1925 and concluding with the opening on October 27, 1928. The opening date on the sign is considered to be incorrect, as it was opened in 1928, not 1927. A plaque behind the 1927 sign reveals the correct date to be 1928.1 Photo taken 07/05/04.
The grand entrance to the Posey Tube is designed to act as a collar to prevent water from seeping into the tube. The tube carries two lanes of traffic one way toward Oakland. The other tube (Webster Tube) carries the southbound direction, and it was not constructed until 1968 due to increasing traffic needs. Both tubes were retrofitted for earthquake safety between 1999 and 2003. Photo taken 07/05/04.
View of the interior of northbound California 61/260/Posey Tube. Photo taken 07/05/04.
California 61/260 emerges from the tube, and a second sign advises travelers to Interstate 880 to prepare to make a right turn. Note the use of the button copy shield that was pasted over a California 17 shield, thus betraying the age of this sign. Photo taken 07/05/04.
After emerging from the Posey Tube, this end California 61 shield is placed, alongside a freeway sign pointing the way to Interstate 880 (Nimitz Freeway). Continue straight ahead on Harrison Street to enter downtown Oakland. Photo taken 07/05/04.
Heading east on 7th Street, the first ramp is for Interstate 880 north to San Francisco (with connections to Interstate 980, Interstate 80, and Interstate 580) via Jackson Street. Continuing straight ahead, 7th Street connects with I-880 south to San Jose and the South Bay. Photo taken 07/05/04.
Freeway entrance for Interstate 880 north and Interstate 980 east from westbound Jackson Street. Photo taken 07/05/04.
This sign for Broadway and north Interstate 880 is found on the on-ramp from Jackson Street. Photo taken 07/05/04.
California 260 (California 61) south
The Webster Street (southbound) and Posey Street (northbound) Tubes, which together constitute California 260, were seismically retrofitted between 1999 and 2003. The Posey Tube was constructed in the 1920s and the Webster Tube was constructed in the early 1960s; both structures are unique to the area and hold a degree of historical value. Both tubes are 4,500 feet long (including approaches), and the Posey Tube was at one time the largest such tube in the world. Unlike many similar structures neither tube uses steel. Photo taken 04/04/04.
Now ascending from the tube, traffic comes up on the west side of the Oakland Inner Harbor Channel. Photo taken 04/04/04.
As California 260 emerges from the Webster Street Tube, the highway approaches an exit for Mariner Square Drive and Marina Village Parkway. Photo taken 04/04/04.
California 260, which is signed as California 61, reaches a right exit to Mariner Square Drive and a left exit to Constitution Way / Marina Village Parkway. Photo taken 04/04/04.
As California 260 enters the downtown area of Alameda, the highway changes from a limited access/substandard freeway into a city street. Photo taken 04/04/04.
Southbound California 160 (Webster Street) at Santa Clara Avenue. Photo taken 04/04/04.
Southbound California 260 comes to its end at the point where Webster Street meets Central Avenue. Official state maps and legislation still consider a northern extension of California 61 north from this point to somewhere near the Maze interchange, but such a highway is very unlikely to be constructed. Photo taken 04/04/04.

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  1. >Alameda Info's Posey Tube

Page Updated June 17, 2007.

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