In 1985 , San Francisco adopted the Downtown Plan , which slowed development in the Financial District north of Market Street and directed it to the area South of Market around the Transbay Terminal . In the early 1990s , the Embarcadero Freeway was demolished following the 1989 Loma Prieta earthquake , freeing up numerous city blocks for development south of the Transbay Terminal . In 1995 , Caltrain agreed to study extending its commuter rail service from its Fourth and King terminus closer to the Financial District , including whether the obsolete Transbay Terminal should be removed , remodeled , or rebuilt . Ultimately , it was decided that the Transbay Terminal should be rebuilt , with the rail extension entering the Terminal under Second Street . In 1996 , then-San Francisco Mayor Willie Brown issued the idea of redeveloping the earthquake-damaged Transbay Transit Center . To that end , Brown tapped his then-new deputy Mayor Maria Ayerdi Kaplan to head the project . Kaplan created , and then became executive director of , the Transbay Joint Powers Authority in 2008
1989 Loma Prieta earthquake
1989 Loma Prieta earthquake
San Francisco Transbay development