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Public Roads - January/February 2017

January/February 2017
Issue No:
Vol. 80 No. 4
Publication Number:
Table of Contents

Preparing for Change

by Heather Holsinger

Improving the resilience of transportation infrastructure to a changing climate involves integrating preparations throughout the decision making process from planning to design, construction, and beyond.


Hurricane Sandy caused this significant flooding at Battery Park Underpass in New York City. Climate change could lead to increased flooding from storm surge in coastal cities as sea levels continue to rise.


Will your State’s transportation infrastructure be affected by the impacts of climate change? If so, how resilient will it be? Officials at the Federal Highway Administration want to help you answer these questions.

The risks associated with climate change and extreme weather events have emerged as significant concerns for the transportation sector in the United States and around the world. The impacts of a changing climate--higher temperatures, rising sea levels, and changes in seasonal precipitation--are already affecting transportation systems and are expected to intensify. Extreme weather, including heat waves, wildfires, drought, flooding, tropical storms, storm surges, and heavy downpours, have the potential to become more frequent and severe as the climate changes, damaging transportation infrastructure and resulting in loss of service and expensive repairs.

“Although transportation infrastructure is designed to handle a broad range of impacts based on the historic climate,” says Michael Culp, team leader for sustainable transport and climate change in FHWA’s Office of Natural Environment, “preparing for uncertainties in a changing climate is prudent to protecting the safety and integrity of the transportation system and the people it serves.”

To better understand the risks of climate change, FHWA is working with its international, State, and local partners. The purpose is to develop tools and approaches to address these risks during all aspects of transportation decisionmaking--from planning and project design to construction, maintenance, and operations.

Read on for highlights of this ongoing work and some anticipated next steps.

The National Policy Context

In October 2009, President Obama signed Executive Order 13514 (Federal Leadership in Environmental, Energy, and Economic Performance) establishing the foundation for coordinated action on climate change preparedness and resilience across the Federal Government. The order directs all Federal agencies to develop climate adaptation plans and policies. Then in June 2011, the U.S. Department of Transportation released a Policy Statement on Climate Change Adaptation, directing the USDOT modal administrations to incorporate consideration of climate adaptation into their planning processes and investment decisions.

Building on the agency-level planning and action required by Executive Order 13514, President Obama issued Executive Order 13653 (Preparing the United States for the Impacts of Climate Change) in November 2013. This order directs Federal agencies “to improve the Nation’s preparedness and resilience” by promoting “(1)engaged and strong partnerships and information sharing at all levels of government; (2) risk-informed decisionmaking and the tools to facilitate it; (3) adaptive learning, in which experiences serve as opportunities to inform and adjust future actions; and (4) preparedness planning.”

Additional executive orders and guidance documents have followed, addressing climate change in specific sectors or through the actions of Federal agencies. For example, the White House Council on Environmental Quality released guidance in August 2016, describing how Federal departments and agencies should consider climate change adaptation in their National Environmental Policy Act reviews. Also, Executive Order 13690, issued in January 2015, established a Federal Flood Risk Management Standard with the goal of ensuring that federally funded buildings and infrastructure are sited and designed to be resilient to future conditions.

Understanding the Risks to Transportation Infrastructure

Since the early 2000s, FHWA has been working to better understand the potential impacts of climate change on the Nation’s transportation system. The initial efforts involved exploratory white papers and workshops followed by in-depth regional studies on the impacts of climate change on the Atlantic and gulf coasts. This research made it clear that one of the more difficult aspects of understanding the risks is obtaining and applying the relevant climate information in the format needed for transportation planning and design. To address this issue, FHWA initiated a number of projects to develop tools and technical assistance to help transportation agencies use relevant climate information to assess vulnerabilities specific to their State or region.

For example, the gulf coast project, in its second phase, focused on the metropolitan planning organization (MPO) region of Mobile, AL. The purpose of this focused study was to evaluate which components of the transportation infrastructure are most critical to economic and societal function in the region, and assess the vulnerability of these components to weather events and long-term changes in climate.

The study’s researchers also developed tools and approaches that transportation officials everywhere can use to determine which systems most need to be protected, and how best to adapt infrastructure to the potential impacts of climate change.

In 2010–2011 and again in 2013–2015, FHWA partnered with additional State DOTs and MPOs to conduct vulnerability assessments. The purpose of these pilots was to help the participating transportation agencies identify vulnerable assets and analyze options for adapting and improving their resiliency. Five teams participated in the first round of pilots, and 19 in the second round. The experiences and lessons learned from the first round helped inform FHWA’s Climate Change & Extreme Weather Vulnerability Assessment Framework, a guide designed to help transportation agencies to conduct vulnerability assessments. Currently, FHWA is updating and expanding this framework based on the results and lessons learned from the second round of pilots.

Moving From Knowledge to Action

Working with State DOTs and MPOs to assess the vulnerability of their transportation infrastructure to climate change remains a priority. Increasingly, however, FHWA is focusing on the integration of climate change vulnerability and risk into all aspects of transportation decisionmaking. In December 2014, FHWA issued Order 5520: Transportation System Preparedness and Resilience to Climate Change and Extreme Weather Events. The order establishes FHWA policy on preparedness and resilience to climate change and extreme weather events.

It also serves to comply with Executive Order 13653 and to further the USDOT Policy Statement on Climate Change Adaptation. FHWA Order 5520 states: “Climate change and extreme weather events present significant and growing risks to the safety, reliability, effectiveness, and sustainability of the Nation’s transportation infrastructure and operations.”

Order 5520 directs the agency to integrate consideration of the risks of climate change and extreme weather impacts and adaptation responses into the delivery and stewardship of the Federal-aid and Federal Lands Highway programs. The order includes a number of specific responsibilities, including developing and providing technical assistance to State DOTs, MPOs, and others in conducting vulnerability assessments. Other responsibilities include encouraging risk-based and cost-effective strategies to minimize climate and extreme weather risks to transportation infrastructure and updating planning, engineering, and operations guidance to include consideration of climate change and resilience to extreme weather events.

Vulnerability of WSDOT’s Transportation Assets
The Washington State Department of Transportation (WSDOT) developed this map of the State showing road segments that have a high, medium, or low vulnerability to climate change. To develop the map, the agency held workshops with maintenance and engineering staff in all regions of the State, asking, “What happens if the climate-related conditions get worse?” Leveraging the knowledge of local staff, the agency also used GIS overlays of climate and asset management data, FHWA’s Climate Change & Extreme Weather Vulnerability Assessment Framework, and climate data from a local university.


Planning for Climate Resilience

Transportation planning processes are comprehensive frameworks for making investment decisions and represent an important opportunity to consider climate change. Going forward, State DOTs and MPOs will be required to take resiliency needs into consideration in their planning processes, as a result of recent changes to transportation law.

The Fixing America’s Surface Transportation (FAST) Act, signed into law on December 4, 2015, expands the scope of the metropolitan planning process to “improve the resiliency and reliability of the transportation system.” It also requires that metropolitan transportation plans contain strategies that “reduce the vulnerability of the existing transportation infrastructure to natural disasters.” For the statewide transportation planning process, the FAST Act expands the scope of consideration to include projects, strategies, and services that will improve the resiliency and reliability of the transportation system.

Integration of Climate Change Into Transportation Decisionmaking


Some transportation agencies already have begun to consider climate change in their planning processes. For example, members of the MPO of Hillsborough County in Florida, as part of their participation in FHWA’s 2013–2015 pilot projects, identified cost-effective strategies to mitigate and manage the risks of coastal and inland inundation. The purpose was to incorporate those strategies into the Hillsborough MPO’s 2040 long-range transportation plan and other transportation planning and decisionmaking processes. The pilot project looked at several critical assets in the region and evaluated mobility and economic impacts if any of those facilities were to be out of service. Gandy Boulevard, part of an important link between Hillsborough and neighboring Pinellas County, was one of the assets evaluated.

The pilot project identified a 0.38-mile (0.6-kilometer) segment on Gandy Boulevard between the Selmon elevated expressway and the raised Gandy Bridge as a critical hurricane evacuation route from adjacent Pinellas County. Following the pilot project, the Hillsborough MPO coordinated with the Tampa Hillsborough Expressway Authority, the owner of the facility, to conduct a followup study. The study looked at additional risk evaluations specific to the vulnerable segment, refining strategies and providing conceptual designs and pre-engineering cost estimates to offer low-risk, high-benefit solutions for implementation. The followup assessment suggests that the approximately $1.9 million adaptation strategies recommended would show a positive return on investment compared to the more than $3million cost to replace the facility.

State DOTs increasingly use asset management plans to make decisions about where and when to invest State and Federal funds in infrastructure improvements to achieve a state of acceptable repair over the life cycle of transportation assets--representing another key opportunity for considering climate change. The Moving Ahead for Progress in the 21st Century Act (MAP-21) requires States to develop risk-based asset management plans for the National Highway System. In addition, MAP-21 section 1315(b)(1) requires the evaluation of reasonable alternatives for roads, highways, or bridges that repeatedly require repair and reconstruction activities.

On October 24, 2016, FHWA published a notice of final rulemaking in the Federal Register describing the process for developing these State risk-based asset management plans. That process includes addressing risks associated with current and future environmental conditions, including extreme weather events, climate change, seismic activity, and risks related to recurring damage and costs as identified through the evaluation of facilities repeatedly damaged by emergency events.

Transportation agencies already are exploring ways to integrate climate change risks into their asset management systems. For example, the North Central Texas Council of Governments participated in the most recent round of FHWA pilot projects on a study to assess how future climate will affect existing and planned transportation infrastructure. The study focused on roads, passenger rail, and the 19airports in Dallas and Tarrant Counties. In recognition of a substantial anticipated change in demand for transportation infrastructure, the project team evaluated the vulnerability of both current and projected mobility and decided to focus the analysis on extreme heat, rainfall and flooding, drought, and the urban heat island effect. The council plans to use the results of the pilot study and proposed strategies to improve the links between asset management and infrastructure resiliency in both project-level and metropolitan transportation planning processes.

Heat Risks Identified in North Central
The map on the left shows heat risks in 2050, and the map on the right shows expected heat risks in 2100. Significant future increases in temperature will accelerate pavement degradation, rutting, and joint failures. The North Central Texas Council of Governments will use this information in long-range planning and asset management.


“There is a widely known saying that ‘everything is bigger in Texas,’” says Jeffrey Neal, program manager at the North Central Texas Council of Governments (NCTCOG). “While the Dallas-Fort Worth Metroplex has consistently been the fastest growing metropolitan region in the United States for the past 5 years, the area has also experienced the tail end of one of the worst multiyear droughts in modern history, several crippling ice storms, the hottest summer on record, and the wettest year on record. The impacts and consequences to the regional transportation system are such that NCTCOG must work with providers and local governments to achieve an appropriate balance between expansion and preservation, because the pursuit of one without the other in mind will ultimately prove to be unsustainable.”

Adaptation at the Project Level

Given the long lifespan of many transportation assets, decisions made today related to the redesign and retrofitting of existing infrastructure, or design of new transportation infrastructure, will affect how resilient the system will be far into the future. To better understand how to account for the impacts of climate change in project development, FHWA is conducting a series of engineering-informed adaptation studies across multiple projects, asset types, and locations.

With the Transportation Engineering Approaches to Climate Resiliency Study, FHWA is refining a multistep process that was first developed under the second phase of the gulf coast project. The new study includes nine engineering-informed case studies of climate vulnerability and adaptation for specific highway facilities across the country. FHWA officials anticipate that the study will be completed in spring 2017.

Several of the 2013–2015 climate resilience pilots included project-level analyses. For example, the Minnesota Department of Transportation (MnDOT) looked at future precipitation and flood risk in developing and evaluating options for hydraulic facilities such as culverts. To evaluate options for two culverts due for replacement in the near term, MnDOT used the multistep engineering process developed during the gulf coast study. For a culvert on Silver Creek, MnDOT included input from climate models and determined that a slightly larger structure would be most cost effective in the long term when considering potential future damages.

In 2014, FHWA published Hydraulic Engineering Circular No. 25–Volume 2--Highways in the Coastal Environment: Assessing Extreme Events (HEC-25, Vol. 2; FHWA-NHI-14-006). The publication provides technical guidance on how to incorporate extreme events and climate change into coastal highway designs, with a focus on sea level rise, storm surge, and wave action. The circular includes case studies and examples of methods at three levels of effort to reflect projects of different magnitudes. The publication is available at

In June 2016, FHWA released a similar update to Hydraulic Engineering Circular No. 17–2nd Edition--Highways in the River Environment: Floodplains, Extreme Events, Risk, and Resilience (HEC-17; FHWA-HIF-16-018). It provides technical methods on how to incorporate floodplain management, risk, extreme events, resilience, and adaptation for highways in the riverine environment. The guidance inthe manual draws on the best action-able engineering and scientific methods and data. The publication is available at

Transportation Operations And Maintenance

Climate change and extreme weather events threaten the ability of transportation agencies to effectively manage, operate, and maintain a safe, reliable transportation system. For example, transportation agencies currently develop maintenance plans using historic climate information. Because of climate change, assumptions regarding the timing of freeze/thaw cycles, snow melt, vegetation growth, rates of weather-related degradation, and optimal times for construction work might need to be revisited.


For culvert 5648, shown here, which carries MN–61 over Silver Creek in Minnesota’s Arrowhead Region, the State used input from climate models indicating that a slightly larger replacement structure would be more cost effective in the long term.


FHWA’s Climate Change Adaptation Guide for Transportation Systems Management, Operations, and Maintenance (FHWA-HOP-15-026) provides specific guidance for integrating climate change adaptation and extreme weather responses into management operations and maintenance programs. For many of the already observed and anticipated weather events related to climate change, operations and maintenance workers, as well as the State DOT emergency responders with whom they coordinate, are the front line of the response. If agencies do not understand the risk to their operations, they can be caught off guard by an unexpected event, leading to significantly degraded capabilities when they are most needed. Additional information on this guide can be found at

Learning From a Disaster

Hurricane Sandy hit portions of the northeastern United States in October 2012. The storm was the largest Atlantic hurricane on record, as measured by diameter, with winds spanning 1,100 miles (1,770 kilometers). The hurricane caused significant loss of life as well as tremendous destruction of property and critical infrastructure.

In the aftermath of the storm and building on one of FHWA’s 2011 pilot projects in New Jersey, FHWA initiated the multimodal study Hurricane Sandy Follow-up Vulnerability Assessment and Adaptation Analysis. The study involves a large number of stakeholders, including State DOT and MPO partners in Connecticut, New Jersey, and New York, as well as the Metropolitan Transportation Authority, Port Authority of New York & New Jersey, andothers.

The study leverages lessons learned from Hurricane Sandy and other recent storms, as well as future climate projections, to develop feasible, cost-effective strategies to reduce and manage extreme weather vulnerabilities amid the uncertainties of a changing climate. These strategies include designing a protective seawall for a tunnel ventilation building so that it can be adapted to future sea level rise and storm surge conditions as needed, as well as relocating flood-vulnerable electrical and mechanical drawbridge equipment. The transportation agencies chose 10 regionally significant facilities--ranging from roads to bridges, rail, and ports--for engineering-informed adaptation assessments. They used results from the storm damage assessments and the engineering-based adaptation assessments to inform a multimodal transportation vulnerability and risk assessment for the region, as well as adaptation strategies for three critical subareas. The study provides lessons learned in addressing climate change risks across the entire transportation life cycle--from planning to operations and emergency response.

The agencies expected the project to be complete by the end of 2016.

The consideration of climate change is also included in guidance for FHWA’s emergency relief program. The May 2013 update to the program’s manual notes that “FHWA supports planning, designing, and constructing highways to adapt to current and future climate change and extreme weather events” when rebuilding a damaged facility with emergency relief funds. If an agency is considering moving a damaged facility, the new location should be evaluated to determine susceptibility to damage from climate change. The manual for FHWA’s emergency relief program is available at

Sharing Adaptation Strategies Across the World

In addition to learning from State and local partners, FHWA is exchanging information with the international community on how DOTs are adapting transportation infrastructure to the impacts of climate change.

For example, FHWA conducted a virtual review to study how transportation agencies worldwide are working to adapt highway infrastructure. The review team spoke with transportation agencies in eight countries, including Australia, New Zealand, the Republic of Korea, and the United Kingdom, among others, on all aspects of the delivery process for transportation projects, including policy development, planning, design, construction, operations, and maintenance. The findings from the review can be found in International Practices on Climate Adaptation in Transportation--Findings from a Virtual Review (FHWA-HEP-15-012).

In September 2015, FHWA cosponsored the Transportation Research Board’s first International Conference on Transportation System Resilience to Climate Change and Extreme Weather Events. The conference and live webcast convened more than 500 experts from across the world to explore state-of-the-art research and emerging practices and policies on adapting surface transportation networks to the potential impacts of climate change and extreme weather. The Transportation Research Board provided a synopsis of the event in its E-Circular 204: Surface Transportation System Resilience to Climate Change and Extreme Weather Events--First International Conference.

Next Steps

FHWA will continue to highlight best practices and develop guidance for incorporating climate risks into system planning, project design, and operations and maintenance.

In addition, the agency is expanding its existing portfolio of case studies highlighting adaptation and resilience activities in the transportation sector. These include information on the recently completed pilot projects as well as research projects conducted by FHWA and other transportation agencies.

Also, FHWA officials are looking across sectors to better coordinate efforts to address climate change resilience, as well as resilience to other potential risks. For example, the FHWA Office of Policy and Governmental Affairs is leading a project to look at the resilience of the National Highway System with respect to risks such as earthquakes and terrorism. The project will be developing metrics and indicators for assessing the resilience of the system and exploring how disruptions to other transportation modes would affect its operation. The project was expected to be completed by the end of 2016.

In addition, a new project called Green Infrastructure Techniques for Coastal Highway Resilience seeks to improve the resilience of coastal roads, bridges, and highways through implementation of green infrastructure and ecosystem-based approaches. The project will investigate techniques that could be implemented as part of transportation planning, construction, and maintenance to preserve and improve natural infrastructure functions, thereby increasing the resilience of highways to the effects of storm surges and sea level rise. Coastal green infrastructure includes dunes, wetlands, living shorelines, oyster reefs, beaches, and artificial reefs. These features can protect coastal transportation infrastructure from the brunt of storm surges and open water waves. Some can adapt to sea level rise by accumulating sediment or migrating inland.


Using FHWA emergency relief funds, the Colorado DOT contracted with FHWA’s Central Federal Lands Highway Division to rebuild this stretch of U.S. 36 between Lyons and Estes Park that was damaged by flooding in 2013. Shifting the road a few feet farther from the river and using grouted riprap and native vegetation to stabilize the riverbank will help make the road more resilient to future floods.


“Although scientists cannot predict precisely how the climate will change across the country, most agree that it will continue to change and cause a range of impacts,” says Emily Biondi, acting director, FHWA’s Office of Natural Environment. “Anticipating and preparing for climate change is essential to maximizing service while minimizing long-term costs. FHWA will continue to work with our partners and stakeholders to ensure that the United States has a resilient transportation system now and in the future.”

Heather Holsinger is an environmental specialist with the Sustainable Transport and Climate Change Team within FHWA’s Office of Planning, Environment & Realty, where she focuses on policy development and analysis in the areas of climate change adaptation, sustainability, and alternative fuel vehicles. She holds master’s degrees from Duke University in resource economics and public policy and a bachelor’s degree from the University of Virginia in economics and environmental science.

For more information, see Or contact Heather Holsinger at 202–366–6263 or