Measuring Success: Using Metrics in Support of Regional Equity

Abstract

Since 1936, the San Francisco-Oakland Bay Bridge has facilitated the movement of people and goods throughout the San Francisco Bay area of northern California. Known locally as the Bay Bridge, the double-decked east span structure carries Interstate 80 and more than 280,000 vehicles per day between Oakland and the Yerba Buena Island tunnel. For years, officials with the California Department of Transportation (Caltrans) had been concerned about the aging bridge and its crack-susceptible eyebar design. After the Loma Prieta earthquake in 1989 severely damaged the bridge's east span, Caltrans officials decided the time had come to replace that span with a new bridge that meets modern seismic and safety standards. The preliminary work started shortly after the Loma Prieta earthquake, and construction continues today as the new structure nears completion. This article summarizes the history, the current status and the future of the Bay Bridge and its newest span, which is designed to withstand the shaking associated with an earthquake seismologists expect to occur only once every 1,500 years. The opening day for traffic on the new bridge is planned for September 2013.