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Interstate 980's roots reach back to the 1950s. In 1959, the Alameda County Transportation Improvement Plan included a six-mile "Grove-Shafter Freeway" following the current 980-24 corridor (with the same incomplete interchange at the Nimitz Freeway).  Grove Street (now Martin Luther King, Jr. Way ) and Shafter Street paralleled the proposed freeway.
Construction began in 1964, but a lawsuit helped delay completion of the freeway until 1985.  When it opened, it was signed CA 24 for a few years before I-980 signs went up. . Officially, however, the route between the Nimitz Freeway and I-580 gained Interstate status on January 29, 1976. 
Some plans for the Southern bay Crossing have had I-980 as a terminus.
A vital backup for collapsed I-880
I-980 became a crucial East Bay link on October 17, 1989, when the Loma Prieta quake collapsed the double-decked Cypress portion of I-880. That highway reopened on a new alignment in 1997.
I-980 is called the John B. Williams Freeway, named after an Oakland community leader (not the blunt-fisted movie score composer). Named by Assembly Concurrent Resolution 52, Chapt. 61 in 1977. [CalTrans]
See also: I-980 (Dan Faigin)