Resilience Of Transportation Networks Research Articles

Policies towards the resilience of road-based transport networks to wildfire events. The Iberian case

Policies towards the resilience of road-based transport networks to wildfire events. The Iberian case

Two-Stage Stochastic Programming Model for Improving Transportation Network Resilience of Relief Supplies in Sequential Hazards Scenario

Cascading failure of road transport networks caused by complex sequential natural hazards adversely affects the use of pre-positioning relief supplies. Therefore, it is vital to improve the transportation network resilience of relief supplies by using an optimization model. The purpose of this paper is to pre-position and distribute relief supplies in uncertain scenarios of sequential hazards. A two-stage stochastic programming model to maximize the total resilience is proposed to provide an optimal plan against the uncertain impact of sequential natural hazards. The combined impact of the Jiuzhaigou 7.0 magnitude earthquake and its associated landslide is a prototype disaster scenario for the implementation of the method proposed in this paper. The model is solved by a neighborhood search-based genetic algorithm (NS-based GA), which has both the global search capability of a genetic algorithm and the local search capability of a large-scale neighborhood search algorithm, can improve the solution finding capability. A case study focusing on finding the optimal solution for the pre-position and distribution of relief supplies in the sequential hazard of Jiuzhaigou earthquake is conducted to illustrate the validity of the proposed model.

Resilience modeling and pre-hazard mitigation planning of transportation network to support post-earthquake emergency medical response

Earthquakes can cause traffic network disruption, extensive blacked-out traffic signals, considerable dislocation trips, and numerous injuries. To avoid injury-transporting private vehicles jamming on few routes on a first-come, first-served basis, existence of redundant routes is essential for transporting injured people to hospitals in a timely manner. To save as many lives as possible, a resilient transportation network with redundant paths between injured people and hospitals is crucial following major earthquakes. This study aims to support the emergency medical response through improving system resilience with a focus on redundancy by integrating post-hazard emergency response and pre-hazard mitigation planning holistically. First, a new methodology to quantify the resilience of transportation networks is developed with two main contributions: incorporating infrastructure fragility, seismic uncertainty, search-and-rescue activity, and life vitality decay of injured people to quantify the urgency of hospitalization trips; and introducing equivalent resistance theory to model the redundancy of road networks. Second, the feasibility of developing a resilience-based pre-hazard mitigation strategy of vulnerable infrastructures to proactively support post-earthquake emergency medical response is investigated. A comparison with existing resilience metrics is conducted to reveal the advantage of the proposed methodology. Shelby County, Tennessee, is selected as the prototype community to demonstrate the proposed framework.

Resilience Assessment of Traffic Networks in Coastal Cities under Climate Change: A Case Study of One City with Unique Land Use Characteristics

How to assess the risk of flood disasters and improve the resilience of coastal cities has become a scientific problem that must be solved urgently. This paper aims to construct a resilience assessment model for transport systems in the context of climate change based on an analysis of the spatial characteristics of regional transport networks and complex network theory, using the Pudong New Area in Shanghai, China as the empirical object. Other objectives of the developed model are to establish a system of homogeneity, efficiency, and stability indicators and to assess the impact of flood depth (up to 7 m) on the resilience of transport networks in terms of static network structure and dynamic network performance by designing flood inundation disturbance scenarios. Finally, the characteristics, change trends, and conceptual connotations of the resilience of transport networks in coastal cities are condensed. The results of this study provide a solid scientific basis for future flood disaster risk management in global coastal cities.

Editorial: The crux of bridge and transport network resilience – advancements and future-proof solutions

Editorial: The crux of bridge and transport network resilience – advancements and future-proof solutions

Identifying Topological Credentials of Physical Infrastructure Components to Enhance Transportation Network Resilience: Case of Florida Bridges

Identifying Topological Credentials of Physical Infrastructure Components to Enhance Transportation Network Resilience: Case of Florida Bridges

Freeway Incident Diversionary Behavior as a Measure of Transportation Network Resilience

Traffic flow disruptions caused by road incidents reduce the performance of transportation networks. Under such conditions, drivers often attempt to reduce delay by diverting to alternate paths, redistributing trips to less congested routes. In the absence of route guidance information, the speed and efficiency of network recovery are most significantly influenced by driver familiarity with a network and, in particular, its daily variability. The goal of this study was to propose metrics and a general formula to relate driver diversionary behavior during incidents to assess resulting actions and conditions from the perspective of network resiliency. Another key objective of the work was to assess the applicability of routine traffic volume data collected by the Louisiana Department of Transportation and Development (LA DOTD) for assessing both driver adaptation and local network resiliency during incidents. The findings from the study suggest that resiliency during incident conditions is not a fixed value for a facility but varies depending on the severity of the incident, opportunities for travel diversion, and the actions of network managers.

Resilience Assessment of Multimodal Urban Transport Networks

With the development of urbanization and the evolution of urban network systems, multimodal urban transport network (MUTN) systems play a vital role in improving network effects and operational efficiency. However, urban transport networks are easily affected by natural disasters and traffic incidents, which can lead to significant human and economic losses. Accordingly, it is vital to be able to assess the resilience of transport networks in the face of various disruptions. This study, therefore, utilizes complex network theory to analyze the resilience of multimodal urban transport networks, with the resilience accessed based on topological indices. The MUTN in Beijing is selected as a case study for simulation analysis. Based on the road network and subway network, a model MUTN is established, and the Monte Carlo method is used to simulate random attacks. The results show that the MUTN in Beijing has good resilience against disruptions. This study guides the evaluation of the overall resilience of multimodal urban transport networks and will be useful for transportation planners and decision-makers in dealing with emergencies and natural disasters in the future.

Seismic Resilience Assessment Strategy for Social and Sustainability Impact Evaluation on Transportation Road Network: A Seismic Liquefaction-Induced Damage Application

Transport networks play a critical role for living communities, as they facilitate the exchange of people and goods and foster economic growth. Improving their resilience against seismic hazards, among which liquefaction is by far one of the most significant and complex, is consistent with most of the Sustainable Development Goals pinpointed by the United Nations’ Agenda. In this paper, an original methodological framework, combining innovative Geo-statistical approaches to analyze soil properties, prediction models for soil liquefaction, and calibrated transport demand models providing the social and economic cost associated with seismic-induced road damages and closures within a renewed Geographical Information Systems (GIS) workspace, is proposed. In particular, based on traditional risk assessment evaluation, an innovative approach to evaluate the exposure in terms of economic loss due to lack of accessibility is presented. The methodology is applied to a district area in northern Italy that underwent a recent seismic event that caused several soil liquefaction phenomena. Results provided by a sensitivity analysis on a stochastic (return period) basis are derived: as the seismic intensity increases, the total social costs increase, but the trend of the rates due to traffic delays and the loss of accessibility are irregular. Although further simulation scenarios need to be undertaken, the proposed methodology seems to provide an effective planning tool to evaluate preventive strategies aimed at improving the resilience of transport networks against liquefaction risk.

An overarching framework to assess the life-time resilience of deteriorating transportation networks in seismic-prone regions

This study develops a comprehensive framework to assess the resilience of transportation networks consisting of deteriorating bridges subjected to earthquake events. For this purpose, the structural capacity of highway bridges is estimated during their service life using a set of detailed finite-element models that simulate the progress of deterioration. The developed models take into consideration the main environmental stressors and determine the extent of capacity loss as a function of time. Based on the degraded state of structural components, seismic fragility analyses are performed to obtain a probabilistic evaluation of the extent of damageability of the existing bridges under seismic events. Since each transportation link normally consists of a number of bridges, the state of damage in the individual bridges is mapped to the corresponding links and a scenario-based approach is employed to estimate the resilience of the entire transportation network. To demonstrate how the consequences of structural degradation can be integrated into the developed framework, the large-scale transportation network of Los Angeles and Orange counties is investigated under a series of aging and earthquake scenarios. The outcome of this study indicates how the estimates associated with the functionality measures of a transportation network can be improved if the age factor is properly integrated into the framework used for resilience assessment.

Resilience Enhancement Strategies For and Through Electric Vehicles

Electric vehicles (EVs) have the potential to reduce emissions from the transportation sector and are also capable of providing several services to the power system including resilience during power outages. However, transportation electrification has increased the interdependence of transport and power networks, which could become challenging during periods of extended outages. Consequently, the analysis of the existing literature on the resilience of power systems and EVs is carried out in two parts in this study. In the first part, the use of EVs as a resilience resource for buildings, microgrids, and power systems is discussed. In addition, the use of exhausted EV batteries (second life) for resilience enhancement purposes and collective resilience of power and transport networks are also discussed. In the second part, strategies used for enhancing the resilience of EVs are discussed, which comprise onsite storage deployment, integration of renewable energy sources, design of off-grid charging stations, energy allocation to EVs during outages, and the use of EVs for evacuation during emergencies. Especially, the need to include EVs in making public policies on disaster management is emphasized. Then, the prevailing challenges for realizing these services are discussed along with the research gaps in the existing literature. Finally, several potential research directions are presented to carry out future research based on the existing studies.

Resilience model and recovery strategy of transportation network based on travel OD-grid analysis

Transportation is the key to a city's prosperity, however, there is possibility that the development and expansion of city make the transportation system complicated, uncertain and vulnerable, especially when in the face of damage. Although resilience is a critical factor for understanding and managing the damage and recovery of the transportation system, study on model of transportation resilience, which is able to effectively utilize actual data and is based on real cases, is still not enough. Therefore, this paper proposes a resilience model and investigates the optimization of the recovery strategy according to this model. It constructs a modeling framework based on the OD-grid network and provides a brand-new performance metric for transportation network resilience analysis based on grid capacity. It also develops two resilience assessment models and compares their characters. Focusing on the recovery of transportation resilience process, it presents two recovery strategies considering recovery sequence and resource allocation respectively and uses the GA algorithm to optimize them and solve the problem. It then demonstrates the effectiveness of the proposed model and the recovery algorithm through the resilience analysis and recovery strategy optimization of a city's transportation network model, which is built according to the real GPS data.

Local impacts on road networks and access to critical locations during extreme floods

Floods affected more than 2 billion people worldwide from 1998 to 2017 and their occurrence is expected to increase due to climate warming, population growth and rapid urbanization. Recent approaches for understanding the resilience of transportation networks when facing floods mostly use the framework of percolation but we show here on a realistic high-resolution flood simulation that it is inadequate. Indeed, the giant connected component is not relevant and instead, we propose to partition the road network in terms of accessibility of local towns and define new measures that characterize the impact of the flooding event. Our analysis allows to identify cities that will be pivotal during the flooding by providing to a large number of individuals critical services such as hospitalization services, food supply, etc. This approach is particularly relevant for practical risk management and will help decision makers for allocating resources in space and time.

Resilient perimeter control for hyper-congested two-region networks with MFD dynamics

Understanding the resilience of transportation networks has received considerable research attention. Nevertheless in the field of network traffic flow control, few control approaches target the mitigation from hyper-congestion, and the control objective has rarely touched the system resilience requirement which focuses on system recovering from hyper-congested state. This paper sheds light on a resilience-oriented network control. We firstly define the traffic resilience as the integral of deviation against optimal state from disturbance generation moment t0 to recovery moment tf. Then, we propose a control method under hyper-congested situations by formulating the analytical problem using a two-reservoir transportation system with parabola-shaped Macroscopic Fundamental Diagrams (MFDs), using phase diagram analysis, attraction region derivation and switched controller design. Afterwards, we evaluate the system resilience performances between two classic perimeter control schemes (constant perimeter control (CPC) and state-feedback control (SFC)) and the proposed resilient control scheme. Results show that proposed controller can ensure the system to recover from hyper-congestion to the optimal state while existing studies failed to recover. This resilience is confirmed in various case study scenarios, e.g., when the level of hyper-congestion is different. More promisingly, the proposed control shows high compatibility with the form of the MFDs, e.g., the recover can be achieved under hysteresis conditions which are common for network-level traffic dynamics. These findings will help to design an intelligent transportation system with enhanced resilience.

Resilience of Transport Networks: A Review of Interpretations and Computational Metrics for Policy Making

Resilience of Transport Networks: A Review of Interpretations and Computational Metrics for Policy Making

Editorial Special Section on Robustness and Resilience of Transport Networks

Editorial Special Section on Robustness and Resilience of Transport Networks

Urban Transportation Networks Resilience: Indicators, Disturbances, and Assessment Methods

Due to a surge in the frequency and intensity of disruptive events, such as natural disasters, the Covid-19 pandemic, and intentional attacks, the concept of resilience has attracted increased attention in recent years. Many scholars have focused on transportation network resilience because of its importance in society's well-being and recovery efforts after disturbances. Existing studies have suggested various definitions, indicators, and methods for assessing the resilience of transportation networks. This variation is due to differences in the nature, scale, and impact of disturbances. This systematic literature review presents resilience assessment methods for transportation networks, indicators, and disturbance categories. A new representation is suggested for the relationships between performance, time, and resilience, emphasizing other network characteristics and their association with resilience. Resilience indicators are categorized, and disturbance categories are analyzed. Approaches are grouped based on their methodologies and presenting their strengths and limitations. This paper directs future studies toward investigating emerging threats, including climate change, pandemics, cybersecurity, failure propagation, and the impacts of new technologies and paradigms on urban transportation resilience. Additionally, it highlights the benefits of identifying a reference metric. Finally, this paper promotes resilience-based thinking to address challenges facing cities worldwide as a cornerstone for creating lasting sustainable development.

Bridge and transport network resilience – a perspective

Bridges and critical transport infrastructure are primary assets and systems that underpin human mobility and activities. Loss of bridge functionality has consequences on entire transport networks, which are also interconnected with other networks. Cascading events then unfold in the entire system of systems, leading to significant economic losses and societal disruption to business and society. Recent natural disasters have revealed the vulnerabilities of bridges and critical assets to diverse hazards (e.g. floods, blasts, earthquakes), some of which are exacerbated due to climate change. The assessment of bridge and network vulnerabilities by quantifying their capacity and functionality loss and adaptation to new requirements and stressors is thus of paramount importance. The aim of this work was try to understand the main compound hazards, stressors and threats that have short- and long-term impacts on the structural capacity and functionality of bridges and the impact of bridge closures on network operability. The main drivers of bridge restoration and reinstatement were also considered. Loss of performance, driven by redundancy and robustness of a bridge, is the first step to be considered in the overall process of resilience quantification. Resourcefulness is the other main component of resilience analysed in this work.

REINFORCE: rapid augmentation of large-scale multi-modal transport networks for resilience enhancement

With the recent and continuous growth of large metropolis, the development, management and improvement of their urban multi-modal transport networks become a compelling need. Although the creation of a new transport mode often appears as a solution, it is usually impossible to construct at once a full networked public transport. Therefore, there is a need for efficient solutions aimed at prioritizing the order of construction of the multiple lines or modes that a transport operator might want to construct to increase its offer. For this purpose, we propose in this paper a simple and quick-to-compute methodology, called REINFORCE, to prioritize the order of construction of the lines of a newly designed transport mode by maximizing the transport network performances and enhancing the transport network resilience, as described by complex networks metrics. REINFORCE could also be helpful to support the rapid and quick response to disruptions by setting up or reinforcing an adapted emergency transport line (e.g., bus service) over a set of predefined itineraries.

Enhancing network resilience by adding redundancy to road networks

In this paper, we develop a new tool to enhance the resilience of transportation networks by optimizing route diversity redundancy from travelers’ perspective. The decision of where to add new links is made to generate as many origin–destination (O-D) pairs with alternative distinct routes as possible to potentially alleviate the impact of disruptions. Mathematically, we formulate the problem as a binary integer bi-level program (BLP), where the upper-level subprogram maximizes the total number of O-D pairs with alternative distinct routes subject to a budgetary constraint, and the lower-level subprogram counts the maximum number of distinct routes between each O-D pair under a given design scheme. Computationally, the BLP model can be equivalently reformulated as a single-level mixed-integer linear program (MILP) by using the equivalent continuous relaxation and optimality conditions of the lower-level subprogram and linearization techniques for the complementarity conditions. The globally optimum solution of the MILP structure of the reformulated model can be obtained using existing algorithms in commercial software packages. Numerical examples are provided to demonstrate the validity, features, and flexibility of the proposed route diversity-oriented network design model in terms of optimizing the network redundancy. The proposed route diversity redundant network design contributes toward enhancing network resilience against disruptions in the pre-disaster stage of transportation network planning and assists in redundancy-oriented time-dependent network growth. It can also serve as an upper-bound solution for the long-term network design problem when travelers’ route choice behaviors and travel demands are considered in the design process.