Abstract
Problem statement: Resilient infrastructure systems are able to continue to provide the expected service levels following disruptive events. Implementing resiliency in infrastructure systems requires knowledge of the current resiliency of the system and a methodology by which different resiliency strategies can be evaluated. In the transportation infrastructure in particular, disruptions cause delays, which will in turn incur substantial economic losses and environmental damages. Approach: The Networked Infrastructure Resiliency framework (NIRA) is proposes to assess the resiliency of the road network that connects Manhattan in New York City to the rest of the regions. The framework proposes to create a network model of the system onto which hypothetical disruptions can be introduced and then to measure resiliency as the impact of disruptions on the performance measures of the system. One of the key performance measures of the transportation infrastructure system is the travel time; hence, the base resiliency of the system is measured as the ratio of the travel time preceding a disruption to the travel time following a disruption. Different resiliency strategies that improve the system’s resiliency can be evaluated through the use of decision tree analysis. Results: The proposed NIRA framework is a novel approach for assessing the resiliency of networked infrastructure system by measuring the impact of disruptions on the system’s performance measures. In road transportation networks, such as that connecting Manhattan entry points, resiliency is achievable through reducing the vulnerability of the system and increasing its adaptive capacity. Conclusion: One vulnerability reduction strategy is the clever assignment of vehicles to other routes in the network. The adaptive capacity of the system is enhanced through the deployment of other parallel systems such as ferries.
Highlights
The issue of infrastructure resiliency has been receiving an increasing amount of interest as a result of the devastating events of September 11th and Hurricane Katrina
Capacity disruptions result in an increase in choose between the alternative strategies and to travel time, which reduces the value of the network evaluate the cost effectiveness of the strategy
The graph shows that a reduction of road capacity of only 20% has an impact on the node-to-node travel time
Summary
The issue of infrastructure resiliency has been receiving an increasing amount of interest as a result of the devastating events of September 11th and Hurricane Katrina. Capacity disruptions result in an increase in choose between the alternative strategies and to travel time, which reduces the value of the network evaluate the cost effectiveness of the strategy. This result indicates that the network with its current capacity is extremely vulnerable to disruptions In some cases such as the Holland Tunnel, reducing the capacity by 20% results in a resiliency value of 0.55, this means that the travel time almost doubles. If no resiliency strategy is knowledge of the disruption, vehicles travelling into implemented and a disruption occurs, the financial loss due to the disruption is Cs. The decision tree is used to calculate the net present value NPV at the decision node over a number of N periods using the dicscount rate r is shown in Eq 14: Manhattan Holland Tunnel will choose to travel over other entry points. It is important to note that the selected values for evaluating the resiliency strategies are not intended to obtain accurate figures for the cost of resiliency but rather to demonstrate the evaluation procedure
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