Historic and interesting bridges and tunnels in the San Francisco Bay Area. KPIX Eye on the Bay had a segment on 5/16/07 covering the Lesser Known Bridges of the Bay Area. This map combines that with the Caltrans Historic Roadway Bridges and Tunnels in California published in 2006. The KPIX identified sites are blue, Caltrans green, and where a site showed up in both lists, purple.