California Senate President Pro Tempore Darrell Steinberg, (D-Sacramento) center, speaks during a press conference on green gas emissions at the MacArthur BART station in Oakland, Calif., on Thursday, May 15, 2014. (Jane Tyska/Bay Area News Group)
California Senate President Pro Tempore Darrell Steinberg (D-Sacramento) speaks during a press conference on green gas emissions at the MacArthur BART station in Oakland, Calif., on Thursday, May 15, 2014. (Jane Tyska/Bay Area News Group)
Consruction is underway as California Senate President Pro Tempore Darrell Steinberg (D-Sacramento) and others speak during a press conference on green gas emissions at the MacArthur BART station in Oakland, Calif., on Thursday, May 15, 2014. (Jane Tyska/Bay Area News Group)
Oakland Mayor Jean Quan speaks during a press conference on green gas emissions at the MacArthur BART station in Oakland, Calif., on Thursday, May 15, 2014. (Jane Tyska/Bay Area News Group)
California Senate President Pro Tempore Darrell Steinberg (D-Sacramento) speaks during a press conference on green gas emissions at the MacArthur BART station in Oakland, Calif., on Thursday, May 15, 2014. (Jane Tyska/Bay Area News Group)