The current tunnel under San Francisco Bay for the Bay Area Rapid Transit system was built in the late 1960s and early 1970s. SPUR, a local think tank, says a second tunnel is needed to connect the East Bay and San Francisco, because the current system will exceed capacity in 2024. The original tunnel cost $1.6 billion, but the organization gave no estimate on the cost of a new tunnel. Read The Examiner story here