Transportation Infrastructure Resilience Research Articles

Estimating, and setting targets for, the resilience of transport infrastructure

To ensure that transport infrastructure provides acceptable levels of service with respect to extreme events, the resilience of the infrastructure needs to be estimated and targets for it need to be set. In this paper, the methodology proposed in the Foresee EU research project is presented. The methodology allows managers to measure, and set targets for, the resilience of transport systems in all situations. It requires clear definition of the transport system and how the service provided and the resilience are to be measured. The methodology allows consideration of the fact that transport infrastructure managers need to estimate resilience with various degrees of accuracy depending on the specific problem to be addressed, the time frame at disposition and the expertise available. These various levels of accuracy are covered by proposing the use of (a) simulations, (b) indicators whose values are directly related to increases in expected restoration intervention costs and reductions in service, and (c) the percentage of fulfilment of indicators. Once resilience has been estimated, the methodology provides guidance on how to set resilience targets with or without cost–benefit analysis. For demonstration, the explanation of the steps of the guideline is supported by their use for a simple transport system.

Methodical Procedure for Creating a New Methodology for Assessing the Resilience of Transport Infrastructure

An important part of risk assessment is the assessment of resilience. Resilience assessment leads to increased safety of the evaluated element. Resilience can be understood in different ways. In general, resilience is the ability of an element to resist, absorb, and adapt to adverse events. To unify the understanding of the area of resilience, it is appropriate to develop a uniform methodology for the assessment of resilience. Such a methodology can unify input and output information, thus facilitating resilience assessment. Transport and transport infrastructure are complicated technical systems that require a specific approach. This article aims to analyse the appropriate methodologies used in the assessment of resilience and to present a proposal for a uniform methodology for the assessment of resilience specific to the transport sector.

U.S. transportation infrastructure resilience: Influences of insurance, incentives, and public assistance

The U.S. economy and way of life are highly dependent on transportation systems, which move goods and people locally, regionally, nationally, and internationally. Major disruptions to transportation networks due to natural hazards, manmade hazards (notably terrorist and cyberattacks), accidents, or infrastructure failure can cause substantial social and economic impacts. Through qualitative and quantitative analyses, including an in-depth review of the literature and semi-structured interviews, we identify barriers to and opportunities for lowering transportation-related disaster losses and for improving infrastructure risk management including the need for better data and metrics to support resilience. Our analyses are supported by a review of transportation-related Public Assistance (PA) expenditures to understand the magnitude and variation of expenditures over time. PA is a U.S. Federal Emergency Management Agency (FEMA) program dedicated to partial reimbursement of hazard-related losses for public infrastructure. Our analyses show that the availability and significant outlays of PA after disasters inhibit risk-based loss reduction actions by infrastructure managers. Risk management tools, notably insurance and mitigation measures, can efficiently reduce disaster losses and speed recovery times. This paper concludes with recommendations for policy measures to facilitate improvements in transportation infrastructure resilience.

Multimodal transportation system protection against sea level rise

Transportation infrastructure resilience is an important component of a region’s ability to recover from natural disasters. While Sea Level Rise (SLR) is becoming inevitable with climate change, little is known of the impact of protection strategies on multiple modes of transport. The present paper proposes a framework where a range of coastal protection strategies are undertaken in the case of one meter of SLR (expected by the year 2100). The methodology incorporates high-resolution hydrodynamic simulations using the Coastal Storm Modeling System (CoSMoS) and traffic simulations using the Multi-Agent Transport Simulation (MATSim) to quantify the potential impact of SLR and protection strategies on both the highway and public transit systems in the San Francisco Bay Area.The results of the traffic simulations are analyzed at the regional and Transportation Analysis Zone (TAZ) levels. Modeling results show that coastal protection of one area will affect the transportation system (sometimes negatively) in areas beyond its vicinity. The improved spatial resolution, and the integration of highway and transit networks in a unified model, reveal transportation phenomena that were not identified in previous studies. By quantifying the impacts on commuters’ mobility in different TAZs, the methodology can be used to develop effective and inclusive strategies against SLR for a given region of interest.

The RESOLUTE project’s European Resilience Management Guidelines for Critical Infrastructure: development, operationalisation and testing for the urban transport system

Critical Infrastructure protection is an issue of priority in Europe, enabling numerous activities for rendering the European Critical infrastructure resilient. A framework for enhancing critical transportation infrastructure resilience could potentially serve as a roadmap for addressing some of the vulnerabilities and criticalities the Urban Transport System (UTS) is facing (e.g. ageing infrastructure, extreme weather conditions, terrorist attacks). Within RESOLUTE project, this need has been addressed, by defining European Resilience Management Guidelines tailored to UTS functions, by developing tools for their operationalisation, as well as by defining performance indicators for assessing their performance. The RESOLUTE pilot that took place in Florence has implemented this approach and the findings show that effective management and continuous monitoring of UTS, with the use of appropriate tools, facilitates the early identification of vulnerabilities and allows for the a priori enhancement of the system’s resilience.

Measuring Transportation Infrastructure Resilience: Case Study with Amtrak

AbstractThis paper describes a case study performed with the US passenger rail service provider Amtrak that developed a metrics framework to measure resilience to climate risk within their Northeas...

Conceptual framework of life-cycle performance measurement: Ensuring the resilience of transport infrastructure assets

Having efficient and effective transport infrastructure (e.g. bridges, roads, railways, airways and tunnels) in place is essential for supporting the economic and social well-being of an economy. External disturbances that emerge as a result of climate change, for example, are impacting its performance. Delivering, managing and maintaining transport assets that are resilient and adaptive to changing environmental conditions have become a priority for many governments worldwide. Central to ensuring that transport infrastructure functions at their optimum and is resilient to external changes is performance measurement, as it enables those processes that need to be modified and improved for enhancing the asset’s adaptability throughout their lifecycle to be identified. Despite the importance of performance measurement in ensuring the resilience of transport infrastructure, it has received limited attention by governments in their policy making. Therefore, this paper provides a review of the extant literature and proposes a life-cycle resilient performance measurement framework (PMF) within transport context. The developed PMF is robust in comprehensively capturing the underlying perspectives that are significant for: (1) understanding the current state of the resilient level of transport assets; and (2) enabling a higher ability of the assets to adapt to environment-related changes in the future. The implications of the proposed framework for transport policy development are also discussed in this paper.

Operational Perspectives Into the Resilience of the U.S. Air Transportation Network Against Intelligent Attacks

Protecting critical infrastructures has been deemed a natural security imperative by the U.S. Government for the past 20 years. The resilience of transportation infrastructures is of particular importance, as they serve a crucial rule in economic development and citizen mobility throughout the world. This paper presents a defender–attacker–defender model to analyze the potential impacts of intelligent attacks and worst case disruptions on the U.S. air transportation network, as well as possible protection steps that could be taken to minimize the negative outcomes of such disruptions. Furthermore, to analyze the effects of intermodal connections on the resilience of the air network, a second layer representing a hypothetical bus network is added to the model and studied. We use these models, supported by publicly available data, to identify routes likely to be attacked by intelligent adversaries and those critical to the resilient operation of the air network in such scenarios. We also demonstrate the potential benefits of intermodal linkages toward maintaining network operations and identify promising research directions for this type of integrated and intelligent transportation system.

Resilience in Intelligent Transportation Systems (ITS)

Many cities are adopting increasingly advanced Intelligent Transportation Systems (ITS). These systems combine connectivity, coordination, adaptivity, and automated response for transportation policy optimization, thus increasing “smartness” and efficiency. However, the control and sensing systems of implemented ITS can open new vulnerabilities, especially to cyber-attacks. Currently vulnerability is managed within the framework of traditional risk assessment that assesses potential failures of the system in response to specified threats. Emerging technologies by their nature have threats that are not fully known, therefore, resilience, defined as the system's ability to recover and adapt to both known and unknown threats, is an emerging area that holds promise for assessing threats to ITS. To illustrate the applicability of resilience to ITS, we conducted a study of network efficiency and resilience in response to random and targeted disruptions of ITS systems in 10 urban areas. Disruptions were generated to affect either intersections or roadways controlled by ITS under different threat scenarios. Modeled attacks, under worst case scenarios, disrupted 20% of intersections causing on average 14.6% more additional delays than the same severity attacks on roadways. Additionally, locking traffic signal states was found to cause more disruption than fully disabling signals. Thus, as cities adopt ITS and other smart systems resulting in potentially unknown vulnerabilities, it is important to consider resilience of transportation infrastructure affected by potential cyber-attacks.

Predicting the Performance of Highway Embankment Slopes

Resilience of transportation infrastructure, such as highway embankments, is critical to avoiding commuter delays and costly repairs. The majority of highway embankments in Louisiana and Texas are in marginal condition because the high-plasticity clays that are used during construction will moisten with time to significantly lower strengths. The ring shear tests demonstrate that the Gamez and Stark [1] empirical correlations are applicable to Texas and Louisiana soils. The soil water retention curves at each site were fitted to the Van Genuchten model [2]. For example, the air entry values vary from 0.013 to 0.053 kPa-1 in Louisiana and from 0.008 to 0.01 kPa-1 in Texas. The implications of this wide range of air entry values is that the matric suction pressure required to saturate and desaturate controls the pore-water pressure build-up during a rainfall event.

Ecosystem and Transportation Infrastructure Resilience in the Great Lakes

The impacts of climate change on transportation infrastructure and ecosystems have garnered growing attention over the past decades. Owing to systemic changes in average and extreme weather events,...

A resilience optimization model for transportation networks under disasters

Natural and/or man-made disasters have caused serious problems in transportation systems due to their unpredictable and destructive characteristics. Under disasters, transportation infrastructure plays an important role in emergency management; however, this infrastructure is also vulnerable because of disasters. One way to describe the vulnerable is through resilience. Resilience refers to the ability to recover from a disruption under unexpected conditions, such as natural and/or man-made disasters. How to enhance resilience of transportation infrastructure under disasters is an important issue when facing natural or man-made disasters. This study aims to measure and optimize transportation resilience under disasters. An optimization model for resilience under the constraints of budget and traversal time is proposed. One special feature is that preparedness and recovery activities are implicitly considered and incorporated within the optimization model. The mathematical model provides a good connection between preparedness/recovery activities and network-level resilience. In order to illustrate the proposed model, a real city network and assumptions on activities of emergency management are used in a series of numerical experiments. Traffic conditions before and after disasters are evaluated by the simulation-assignment model, DynaTAIWAN. Experiments and results illustrate advantages for network-level transportation resilience assessment and also prioritize preparedness and recovery activities under budget constraints.

Empirically quantifying city-scale transportation system resilience to extreme events

This article proposes a method to quantitatively measure the resilience of transportation systems using GPS data from probe vehicles such as taxis. The granularity of the GPS data necessary for the method is relatively coarse; it only requires coordinates for the beginning and end of trips, the metered distance, and the total travel time. The method works by computing the historical distribution of pace (normalized travel times) between various regions of a city and measuring the pace deviations during an unusual event. Periods of time containing extreme deviations are identified as events. The method is applied to a dataset of nearly 700 million taxi trips in New York City, which is used to analyze the city transportation infrastructure resilience to Hurricane Sandy. The analysis indicates that Hurricane Sandy impacted traffic conditions for more than five days, and caused a peak delay of two minutes per mile. Practically, it identifies that the evacuation announcements coincided with only minor disruptions, but significant delays were encountered during the post-disaster response period. Since the implementation of this method is very efficient, it could potentially be used as an online monitoring tool, representing a first step toward quantifying city scale resilience with coarse GPS data.

Static and dynamic resilience of transport infrastructure and demand: the case of the Athens metro

Abstract The paper conceptualises the resilience engineering of the urban transport system (UTS) using the example of the Athens metro. Resilience management guidelines for the UTS have been developed, whereas Athens metro pilots validate the former. The pilots are concerned with the metro attack risk and its consequences. The risk scenarios consider the static and the dynamic resilience of the UTS system with respect to metro threats. The identified actions have measurable impacts improving the UTS resilience in Athens.

Predicting the resilience of transport infrastructure to a natural disaster using Cox’s proportional hazards regression model

Transport infrastructure is at significant risk of direct damage from extreme climate events such as flooding, where the cost implications of delayed recovery are generally significant. Previous research in this regard has focused on the technical and engineering aspects of infrastructure construction. The risk management of resilient transport infrastructure is poorly considered, and little has been done to quantify the capacity of transport infrastructure to recover from the impact of natural disasters under varying conditions. This paper applies Cox’s proportional hazards regression model to determine the rate of recovery and cumulative probability that recovery occurs for transport infrastructure across regional areas in New South Wales, Australia. Data for post-disaster reconstruction projects over the period 1992–2012 are used to analyze recovery rate against geographic region, natural disaster type and post-disaster transport infrastructure reconstruction cost. Results demonstrate that transport infrastructure recovered slowest when the failure is the result of a flood rather than bushfire or storm, and in regions with a riverine geography. To validate the accuracy of the model, a bootstrap resampling technique is used. The bootstrap result confirms that the model is robust and reasonable.