Micro-simulation of large scale evacuations utilizing metrorail transit

Public transit plays an important role in emergency evacuations, particularly for areas where public transit serves as a major commute mode for commuters. Micro-simulation techniques provide great flexibilities in assessing different scenarios in emergency situations. Assuming a sudden attack on the Pentagon, this study employs micro-simulation techniques to investigate the performance of the Washington Metropolitan Area Transit Authority's Metrorail for a large-scale evacuation. This study aims to identify the evacuation demand for individual Metrorail lines and the corresponding evacuation times under three different scenarios. Based on 2000 Census Transportation Planning Package Part 3 Journey-to-Work data, this study determined the number of commuters who worked at the Pentagon. Based on this population, this study designed a base scenario in which 1,371 Pentagon workers need to be evacuated using the Metrorail service. To accommodate additional workers who might choose to use Metrorail for evacuation, this study evaluated another two scenarios. The evacuation population was doubled in Scenario 2 (2,742) and tripled in Scenario 3 (4,113). Scenario 3 could represent a worst-case scenario in which almost 20 percent of the Pentagon's total workforce needs to be evacuated.;A network-based analysis was performed to estimate the number of riders in association with each metro line and station. VISSIM, a multi-mode micro-simulation software package, was employed to evaluate the performance of the Metrorail for the three scenarios. Results revealed that total evacuation time for Scenario 1 is about an hour. It took an hour and 14 minutes in Scenario 2 and an hour and 22 minutes in Scenario 3. Comparing the performance measures across three scenarios, this study found that the primary determinant in evacuation clearance time appears to be the rate at which evacuees arrive at Pentagon Station. Overall, the simulation results suggested that none of the scenarios caused any delays worthy of attention for the Metro system. The Metrorail is fully capable of accommodating the large-scale Pentagon evacuations in this study. My findings indicate that if the potential of rail transit is effectively utilized, rail transit could be very efficient for evacuations. This study reduced the void in the literature addressing the specific roles of rail transit in emergency evacuations. It also helps shed light on how to design effective evacuation plans based on public transit systems.