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59 Summary The focus of this project was to better understand how resilience is being addressed by transportation agencies in their planning, engineering, operations management, policy, and administrative actions. The information provided detailed the evolution of policies that pro- mote highway resilience, definitions of risk and resilience and the relationship between these two concepts, and how agencies are incorporating resilience practices through project devel- opment, policy, and design. The information contained in this report was gathered through three primary sources: a literature review, a survey of state DOTs, and five case examples developed through interviews with infrastructure agencies incorporating resilience into their programs. The literature review was concentrated on the evolution of policies from risk identification and management toward understanding and assessing system resilience, meaning the ability of a system to absorb and recover from events that disrupt normal operations. Efforts were also made to review a range of definitions of resilience within and outside of the transportation sector, and an effort was made to provide information on the relationship between risk and resilience to help clarify the two concepts. Next, efforts were made to document resilience metrics that have been developed within the transportation sector, and it was noted that many of the documented examples lack in their ability to capture the full range of the Rs of resilience. A review of a few indices that have been used to reflect resilience was provided, and the literature review concluded with a summary of frameworks that have been developed to help agencies begin to assess the resilience of their systems through detailed processes. Next, the findings of a survey of 40 state DOTs were presented. Questions were developed to serve as a screening tool to identify agencies willing to participate in the case examples presented in chapter 5. Through the survey, information was gathered on the state DOTsâ use of resilience in their various management areas; the resilience assessments that have been conducted and at what level; information on metrics being used; and most importantly, what information state DOTs are seeking to better assess system resilience. Finally, five case examples were developed to demonstrate innovative approaches to resil- ience assessment and incorporation of resilient practices. The case examples were developed for ADOT, Colorado DOT, DelDOT, PANYNJ, and GTC. Each of the case examples reviewed the evolution of resilience analysis within each agency and included details on areas of applica- tion. Information also was included on changes to agency policy and procedures as related to resilience assessment. The case examples demonstrate various levels of maturity within the agen- cies for resilience assessment and capture the lessons learned from each agency with regard to resilience policy, modeling, inclusion in design standards and practice, and unique mechanisms being used to fund resilience practices. C H A P T E R 6 Conclusions
60 Resilience in Transportation Planning, Engineering, Management, Policy, and Administration Findings A review of national policies found that while resilience policies are becoming well estab- lished, there is a lack of integrating resilience into practice within transportation. With the recent requirements for risk-based asset management plans, it is possible that state DOTs have yet to fully complete those requirements and are struggling to address capturing resilience within their management approach. There also has yet to be strong guidance developed on the relationship between risk and resilience, which would be helpful to allow agencies to understand how their risk assessments can help support their system resilience analyses. In addition, although policy touts the need for resilient systems, the lack of monetary assessment of the value of system resilience makes it challenging for agencies to stretch limited dollars in another direction when already faced with challenges related to new performance metrics such as safety, infrastructure health, and operational reliability. The relationship between each of these metrics and system resilience has not yet been fully flushed out in an easy-to-use guidance or modeling tool to assess resilience and reflect the relationship between mandatory performance metrics and resilience, so implementation will continue to be a challenge at state DOTs. The literature review identified shortcomings in the definition of resilience, the quantitative relationship between risk and resilience, and metrics to measure resilience. Much of the focus of resilience definitions is on the ability to recover post event; however, a DHS study was reviewed that helped to define key discriminators for resilience definitions to address the full range of time periods in which resilience is needed to be addressed by asset managers and owners and reflect four goal areas (maintaining continuity of function, graceful degradation, recovery of function to desired function in designated time, and inhibiting basic state of change). The reflection of definitions against the key discriminators provided by DHS for infrastructure systems may be of use to state DOTs as they move forward with their resilience programs as a way to help identify resilient practices and policies that address a broader range of activities that can be implemented to provide more than quick recovery post event to transportation assets. Resilience metrics also appear to be lacking in quantitative measures that can be readily calculated and assessed. Much of the published peer-reviewed literature focuses on using existing operational metrics normally related to system reliability as surrogates to reflect recovery time as a measure of system resilience. Some researchers have attempted to measure characteristics such as the angle of deterioration and recovery triangles during weather events on interstate systems. This approach appears to have promise with the availability of histori- cal traffic performance data at the micro- and meso-scales. In general, however, it appears that agencies are struggling to measure system resilience, as was reflected in the state survey reviewed in chapter 4 of this report. The survey of state DOTs revealed that most respondents are working to incorporate resil- ience into their management programs; however, a closer look at their response to questions related to information needed revealed that agencies are seeking information on resilience met- rics and assessment methods, criticality assessment models, asset vulnerability, and the expected benefits from mitigation measures. Given the lack of documented metrics for resilience in the literature review and the request of additional data from states on how to measure and assess resilience, this appears to be a pressing need to fully address resilience in transportation systems. Conclusions Based on the information gathered through three distinct sources of data (literature review, state DOT surveys, and case examples), the three primary challenges for state DOTs for incor- porating resilience into their management programs appear to be the following:
Conclusions 61 ⢠A lack of understanding of how resilience is related to risk assessment; ⢠A lack of metrics to measure system resilience and the benefits expected from resilience investments; and ⢠A lack of clear direction as to how system resilience can affect mandated transportation performance measures such as safety, infrastructure condition, and system operations and vice versa. Much of the information related to highway system resilience appears to be disjointed in that climate change, risk assessment, asset deterioration as reflected in asset management plans, operational performance, and safety performance have yet to be fully integrated to demonstrate how each affects the other. In addition, the lack of clear metrics to measure system resilience leaves agencies to struggle to implement resilient practices. Finally, data to support such analy- ses, such as the expected performance or benefit derived from mitigation measures implemented to improve system resilience, make it difficult for agencies to justify investments as compared to model and data-rich areas such as operational or safety performance when competing from the same limited pool of funding. Simply stating that a design or maintenance activity will improve system resilience will not go very far in the funding allocation process when other management areas have well-established data sets, metrics, and models to forecast expected performance. National research could address these shortcomings to further advance the integration of resil- ient practices into highway programs.
