
Vulnerability of Transportation Networks
INTRODUCTION
Subway disruptions can lead to major delays with far-reaching impacts on urban economies, security, and quality of life. It is crucial to measure and compare the vulnerability of subway systems of varying network size and
structure.
Objective
Evaluate the impacts of different levels of disruptions in subway system.
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Single node disruptions
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Paired disruptions
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Synergistic effects arising from multiple disruptions
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“the whole is greater than the sum of its parts”.
A Tale of 5 Cities
New York City
London
Singapore
Taipei
Washington, DC


RESULTS
Network Structure
The subway system is modeled as a directed network, weighted by time.
Nodes:
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stations (master nodes)
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lines within each station (sub nodes)
Edges:
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travel time
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transfer time
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wait time

Constructed Network




AM Travel Flow
London and Washington, DC
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Clear home-to-work flow.
Singapore and Taipei
Passenger flow in more evenly distributed across the network.

Criticality Score
