University of California Transportation Center

The Loma Prieta earthquake of October 1989 damaged highways throughout the Bay Area. For many of the damaged facilities, parallel routes or minor detours provided reasonable alternatives and were quickly put to use by travelers. Although congestion and travel time increased, the alternative routes permitted most trips to be made with relatively little disruption. In the case of the San Francisco-Oakland Bay Bridge, however, no close substitute was available. The Bay Bridge had lost one section of the upper deck during the quake and was closed for about a month while the California Department of Transportation made repairs. With 245 thousand vehicles and nearly 400 thousand people routinely crossing the bridge each day, the closure of the Bay Bridge had the potential to cause substantial disruption.