I-5W and the San Francisco Bay Area Interstate 5W (
I-5W) was originally conceived as part of a loop Interstate with a directional suffix and was what is now I-580 from I-5 to Oakland. However, I-5W and most of the other Interstates around the country with directional suffixes were eventually renumbered or eliminated, except for
I-35E and
I-35W in Texas and Minnesota, and more recently in Texas, the designations of
I-69W,
I-69C, and
I-69E, along with proposed suffixed segments for future extensions of
I-14 and
I-27. The former route of I-5W now corresponds to I-580 from I-5 to Oakland, I-80 from Oakland to
Vacaville, and
I-505 from Vacaville to I-5 near Dunnigan.
I-5 to Castro Valley For the most part, the I-580 freeway in this segment was constructed over or alongside the
right-of-way of
US 50, previously part of the old
Lincoln Highway, during the course of the late 1960s and early 1970s. The segment which begins at the split with I-205 was constructed during the same period of time over a new right-of-way, running through some low hills on the west side of the
San Joaquin Valley near the city of
Patterson to a junction with I-5. In the 1990s, the freeway segment from Castro Valley through Pleasanton was enlarged and otherwise reengineered in conjunction with the construction of the
Blue Line of the
Bay Area Rapid Transit (BART). The BART tracks were placed in a new median between the westbound and eastbound lanes of I-580 as was the new
Dublin/Pleasanton station. The interchange with
I-238 and the
Hayward exit ramps was also reengineered at this time. Significant expansion to the segment between I-680 and I-205 began in 2006. Among the projects along this segment were the
high-occupancy vehicle lanes in each direction, a westbound auxiliary lane between Fallon and Tassajara roads, a new interchange at Isabel Avenue in Livermore, the reconstruction of several interchanges, the construction of additional truck climbing lanes for the eastward ascent to the Altamont Pass, and plans to preserve the right-of-way to accommodate a future BART extension in the median of the freeway. In 2017, citing lack of interest from the
Bay Area Rapid Transit District in bringing BART service east to Livermore, the Livermore City Council proposed a newly established local entity to undertake planning and construction of the extension, which was also recommended by the California State Assembly Transportation Committee. Assembly Bill 758 was signed by then-
Governor of California Jerry Brown on October 13, 2017, formally establishing the Tri-Valley–San Joaquin Valley Regional Rail Authority to construct and maintain the alternative
Valley Link commuter rail.
MacArthur Freeway: Castro Valley to Oakland The I-580 freeway in this segment was constructed starting in February 1960, adjacent to the city streets which were part of US 50 between
Castro Valley and the large interchange along the eastern approach to the
San Francisco–Oakland Bay Bridge in
Oakland now called the
MacArthur Maze. The freeway was named in honor of World War II General
Douglas MacArthur. Prior to the construction of this freeway, the various city streets of Oakland that were designated for US 50 (principally 38th Street, Hopkins Street, Moss Avenue, Excelsior Avenue, and part of Foothill Boulevard) had been renamed for the General as "MacArthur Boulevard" which, for the most part, still parallels the MacArthur Freeway. The renaming occurred on March 26, 1942, by a resolution of the
Oakland City Council. The freeway was opened to traffic in eight segments until its completion in May 1966 (last segment, connecting with
SR 238 (now
I-238), in Castro Valley, opened May 20, 1966). It required several buildings and structures to be demolished along its route, including 160 about homes in Oakland's
Trestle Glen.
Oakland to San Rafael The segment of I-580 running from the
MacArthur Maze to
San Rafael is the most recent to be signed as I-580, beginning in 1984. Before 1984, this segment was part of
SR 17. From the Maze to the interchange locally known as the "Hoffman Split" in
Albany, just north of the Gilman Street interchange (Hoffman Boulevard was the predecessor of I-580 in this section), I-580 follows the
Eastshore Freeway, a
wrong-way concurrency with I-80 for its entirety: northward on the Eastshore is signed I-80 east and I-580 west; headed southward, one finds signs indicating I-80 west and I-580 east. At the Hoffman Split, I-580 leaves the Eastshore Freeway in a northwesterly direction through the cities of Albany and
Richmond. It then crosses
San Francisco Bay over the
Richmond–San Rafael Bridge. The freeway in this section, officially named the John T. Knox Freeway, was constructed from 1987 to 1991. It replaced a number of city streets which comprised the earlier highway leading to the San Rafael Bridge, principally, Hoffman and Cutting boulevards. After crossing the bridge, I-580 runs west to
San Rafael, ending at an interchange with
US 101. This freeway segment supplanted an earlier boulevard constructed as part of SR 17.
Interstate 180 Interstate 180 (
I-180) was a temporary designation used in 1978 for the
Richmond–San Rafael Bridge, now part of I-580. At the time, the bridge had been identified as part of
SR 17 but was marked for inclusion in the Interstate Highway System. Briefly the bridge used the number 180, despite the
Fresno-area
SR 180's use of the number. The California Streets and Highways Code has a policy against using one route number for multiple noncontiguous highways. Unless the existing SR 180 is renumbered, which is unlikely due to its familiarity as the road to
Kings Canyon National Park, there will not be an I-180 in California. ==Exit list==