Although I-980 physically goes north and south, it is signed as an east-west route like SR 24. Immediately after traffic leaves I-880 on elevated connector ramps, I-980 then descends below grade to pass under downtown city streets. The freeway then ascends above grade to pass over San Pablo and 27th Street before reaching I-580 and SR 24. The freeway itself lacks overhead guide signs mentioning I-980. Immediately after Exit 1B - 17th Street/San Pablo Avenue going eastbound on I-980 is a guide sign mentioning the junction with I-580. Likewise, the guide signs on westbound I-980 at Exit 1D - 18th Street list I-880 and San Jose as a control city. Since 2018, Jackson Street and I-880 south have been signed as exit 1B and 1A in the westbound direction. I-980 is part of the California Freeway and Expressway System, and 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.
History
I-980 was added to the state highway system in 1947 as part of Legislative Route 226, and to the California Freeway and Expressway System in 1959. This segment of Route 226 became part of State Route 24 in the 1964 renumbering. The Federal Highway Administration approved the addition of the roadway to the Interstate Highway System in January 1976, with Interstate funding only used west of San Pablo Avenue, and the number was legislatively changed to 980 in 1981. Construction on Interstate 980 began in the 1960s, but was not completed until 1985; officially the freeway was designated as I-980 from its opening. The surface roads which existed prior to the completion of the freeway had been designated as State Route 24. It is assumed by many that had the San Francisco Bay Southern Crossing ever been built, it would have carried the designation of I-980; this remains purely speculative, however. The San Francisco Chronicle reported in November 2015 about a grassroots organization of local architects and planners, and supported by Oakland mayor Libby Schaaf, that propose to replace I-980 with a landscaped city boulevard. is coordinating the push for a replacement. Arguments for replacement focus on the freeway's low volume of traffic and negative impact on surrounding neighborhoods. In January 2017, I-980 was included in the Congress for the New Urbanism "Freeways without Futures" report.