1MEASURING LIFELINE SYSTEM PERFORMANCE: HIGHWAY TRANSPORTATION SYSTEMS IN RECENT EARTHQUAKES

Discussion of seismic performance standards for engineered structures and systems involves the issue of how to best measure performance. Moreover, summary measures of post-disaster system disruption and recovery are useful for evaluating the ensuing economic impact and for making comparisons across events. Measurement of lifeline system performance is particularly complex because of network and spatial characteristics, the multiplicity of users, and the critical nature of lifeline services for post-disaster response and recovery. This paper addresses the measurement of lifeline system performance by focusing on highway system disruption in three recent urban earthquake disasters in the U.S. and Japan-- the 1989 Loma Prieta, 1994 Northridge, and 1995 Hyogoken-Nanbu (Kobe) earthquakes. Several alternative measures of the physical performance of highway systems are proposed, implemented, and compared. The paper further analyzes the correlation between these measures and observed traffic conditions in Northridge and Kobe. Results suggest that some measures may be used advantageously in further study of the economic impact of highway damage in earthquakes