Transportation problems faced after big earthquakes
Transportation facilities and services provide the cornerstones to the rescue and response operations after a big earthquake. This study appraises the transportation actions taken by the authorities in the immediate aftermath of the Loma Prieta Earthquake of October 17, 1989. The failure of several transportation structures had a significant impact on rescue operations, traffic congestion and change in travel patterns in the San Francisco Bay Area. Emphasis is placed on travel demand management strategies adopted to meet the travel needs in the Bay Area and to return traffic to normalcy. The short-term and long-term impacts of closures of certain highways due to a 7.5 magnitude earthquake are also addressed in this research.
Recent predictions by the United States Geological Survey show that there is a 67 percent chance of a big earthquake of 7.5 magnitude happening in the Bay Area before the year 2020. Therefore, there is a dire need to look at the transportation problems that the Bay Area might face if the "Big One" really hits. It is also important to note that certain bridges play a major role in the cross-bay transportation. Hence, the failure of such critical links would greatly influence the mobility of the citizens in the region. A macro-level measure referred to as "Weighted Roadway Congestion index" (RCIW) is developed to assess the severity of the closures of these links. To fulfill this objective, scenario analysis is performed for the expected closures in the San Francisco Bay Area. It is important to note that the macro-level measure developed is applicable only to urban areas. This research also aims at identifying the key network parameters, such as number of lane-miles per freeway exit and freeway network connectivity that impact roadway congestion after earthquakes.