Transportation system demand and performance immediately after an earthquake

Rahimian, Sekine.
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University of Delaware
Transportation systems are a class of critical civil infrastructure systems that must be able to respond to disruptions while continuing to provide mobility as well as reduce both human and property loss when disasters occur." In the aftermath of these catastrophic events, emergency response trips are among those most sensitive to delay. Considering the importance of the emergency trips and the special case of a damaged network after a disaster, the goal of this research is to develop a method to evaluate the performance of the transportation system, specifically for emergency response trips, after an earthquake. The first step in reaching this goal is to understand the particulars of the hazard itself and how the transportation system should be prepared. A limited number of earthquake scenarios, representing specific historical data and the possible events that occur in the aftermath, have been chosen to represent the hazard. The impact of each of these scenarios on the transportation components - specifically, bridges - is estimated in this research. In the following step, models predicting a number of emergency response trips have been developed, followed by both supply and demand side is simulated with a macro simulation software. Travel delay and other measures to evaluate the performance of the transportation system are also calculated. Lastly, areas susceptible to the greatest delay for emergency response trips are identified and countermeasures to reduce the delay are proposed. This method is used for two case studies: one in Newark, Delaware, and one in the San Fernando Valley of California. The Newark case study is used to understand the application of the methodology using a familiar network even though the area is not inherently vulnerable to earthquakes. The results of the analysis are as expected with relatively minor impacts. The San Fernando Valley case study used forty-nine earthquake scenarios. The analysis underscored the difficulties of accessing some of the more remote parts of the network, identifying areas underserved by medical and fire centers, and identified bridges that could impact the effectiveness of emergency response. While emergency response trips are relatively small in number, the analysis demonstrates that in some areas these trips may be significantly impacted by disruption to the transportation network. These disruptions require understanding the demand for emergency response trips and understanding how these trips use the transportation network.