Strategic Issues Facing Transportation, Volume 2: Climate Change, Extreme Weather Events, and the Highway System: Practitioner’s Guide and Research Report (2014) / Chapter Skim
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Research Report P A R T I I
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117 S U M M A R Y This report presents the findings of a research project that explored the potential impacts of climate change and extreme weather on the U.S. highway system.
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118 • Increasing population growth will create new demands for transportation infrastructure and services, once again in areas that are vulnerable to changing climate conditions. • The nation's highway system will be facing increasing demands for reconstruction and rehabilitation over the next 40 years (to 2050)
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119 Step 5: Conduct risk appraisal of asset(s) given vulnerabilities.
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120 for this uncertainty, most studies have relied on qualitative or subjective assignment of risk. Thus, "high," "medium," or "low" is often used to indicate the level of risk associated with individual assets.
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121 1.1 Introduction Climate change has received increasing attention worldwide as potentially one of the greatest challenges facing modern society. This attention has focused particularly on two topics.
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122 In addition to the direct effects on road infrastructure, changing climate conditions can affect many of the ecological functions of lands surrounding roads, and possibly influence existing wetland and habitat banks and environmental mitigation strategies that are commonly considered today by state transportation agencies as part of the project development process. Thus, future highway projects might face very different environmental mitigation requirements than they do today.
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123 significant a challenge in most coastal parts of the country. Thus, projections of sea-level rise were provided for both years 2050 and 2100.
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124 2.1 Introduction This chapter describes the approach followed in conducting the research. Given the multidisciplinary nature of the topic, the research utilized expertise in transportation engineering/ operations, systems analysis, planning, climate science, policy, and construction/maintenance in a multi disciplinary research design.
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125 was used to target potential components of road infrastructure design that could be affected by changes in environmental conditions (Meyer 2008)
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126 conditions. Changes in pore water pressure can have significant effects on the shear strength of soils, and in fact it is a change in soil shear strength that has caused many failures in ground slopes (e.g., mud slides)
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127 Structures In the context of this report, structures will primarily refer to bridges. Consistent with the previous discussion on how engineers account for different physical forces when developing a design, civil engineering has a long history of research and practical experience with understanding how such forces act upon buildings and bridges [see Ellingwood and Dusenberry (2005)
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128 frequently or channel flows were to become more turbulent, the engineer would potentially have to rethink the design of such foundations (Sturm 2001)
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129 related to specific design components. Most of these concerns relate to either maintenance practices or environmental mitigation and/or avoidance strategies.
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130 interconnections among different modes serving a variety of purposes. Examples of such interconnections include inter modal passenger and freight terminals, park and ride lots, access roads to freight intermodal facilities, and pedestrian/ bicycle facilities connecting to transportation stations or ter minals.
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131 out over an entire state, the need to be cognizant of changing local environmental conditions and their potential impact on the agency's assets could be an important concern to future managers. 2.4 Summary This chapter presented a multilevel perspective on potential impacts of climate change on the built and yet-to-bebuilt highway system.
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132 3.1 Introduction The Intergovernmental Panel on Climate Change (IPCC) Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation discussed how combining knowledge about climate science, disaster management, and adaptation can inform discussions about managing the risks of extreme events and disasters in a changing climate (IPCC 2012)
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133 Framework General Infrastructure Country Agency/Organiza on Climate Change Risks to Australia's Coast: A First Pass Na onal Assessment Australia Department of Climate Change (2009) Climate Change Risks for Coastal Buildings and Infrastructure: A Supplement to the First Pass Na onal Assessment Australia Department of Climate Change and Energy Efficiency (2011)
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134 the planning, operations, policies, and programs of the agency (U.S.
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135 Source: FHWA (2012a) Figure II.4.
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136 The policy suggests multiple approaches for comparing and selecting desirable alternatives, including: 1. Use a single scenario and identify the preferred alternative under that scenario.
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137 California In response to a gubernatorial executive order, the California Department of Transportation (Caltrans) developed guidelines for considering sea-level rise in project planning documents (Caltrans 2011)
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138 rising water levels)
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139 elevations will need to be designed to withstand colder temperatures and icing events." The types of climate change–related impacts anticipated in the region include the following: 1. Increase in flooding occurrence and intensity, especially tied to severe storms.
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140 for climate adaptation over and above the benefits associated with the project justification process were indicated on the prioritization list. King County, Washington King County developed its Preparing for Climate Change: A Guidebook for Local, Regional, and State Governments in conjunction with its Climate Plan (Center for Science in the Earth System and King County 2007)
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141 disaster preparedness plan, were used to estimate losses from storm flooding (based on the facility's location in flood zones)
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142 Key provisions of the act specific to adaptation are: • A requirement for the government to report at least every 5 years on the risks to the United Kingdom of climate change and to publish a program setting out how these will be addressed; • The introduction of powers for the government to require public bodies and statutory undertakers to carry out their own risk assessment and make plans to address those risks; and • An Adaptation Subcommittee of the Committee on Climate Change, providing advice to, and scrutiny of, the government's adaptation work. The United Kingdom has produced the Climate Change Risk Assessment (CCRA)
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143 understand the climate change itself, needing to better understand the impact of climate change on operations, or to better understand and evaluate the treatment options)
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144 Stage 3: Identify Highways Agency Vulnerabilities. Vulnerabilities are the Highways Agency activities that could be affected -- positively or negatively -- by climate change.
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145 3.4 Diagnostic Framework A diagnostic framework provides highway agency staff with a general step-by-step approach for assessing climate change impacts and deciding on a course of action. A framework can be applied from the systems planning level down to the scale of individual projects.
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146 threat, the impact to the integrity and resiliency of the system will vary. Given limited resources and thus a constrained capacity to modify an entire network, some agencies might choose to establish policies that limit their analysis to only those assets that are critical to network performance or are important in achieving other objectives (e.g., protecting strategic economic resources, such as major employment centers, industrial areas, etc.)
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147 Step 6: Identify Adaptation Options for High-Risk Assets and Assess Feasibility, Cost Effectiveness, and Defensibility of Options Identifying and assessing appropriate strategies for the challenges facing critical infrastructure assets is a core component of the process shown in Figure 8. Such strategies might include modifying operations and maintenance practices (such as developing and signing detour routes around areas at a heightened risk of road closure)
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148 4.1 Introduction The impact that climate change could have on the future transportation system depends on both the changes to society and the transportation system that supports it, and the magnitude and nature of the climate changes that will take place. This chapter provides an overview of potential demographic, land use, and transportation system changes in coming years, and projections for key climate change drivers based on up-todate climate modeling.
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149 particularly high vulnerabilities to projected sea-level rises and potential changes to hurricane intensity and frequency. Similar to other western nations, the U.S.
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150 In summary, five major "contextual" messages have been identified in this research that relate to how socioeconomic and transportation system characteristics could affect the magnitude and direction of climate change impacts on the transportation system: • Message 1: The U.S. population will continue to grow, with most of this growth occurring in urban areas and in parts of the country expecting notable changes in climate.
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151 Note: This figure presents change in temperature across the United States. It is based on output from MAGICC/SCENGEN, which reports data in 2.5 degree grid boxes.
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152 from the GCMs to estimate climate changes quickly for GHG emissions scenarios, as well as other parameters for any region of the world. It is generally considered better to use multiple GCM outputs rather than a single model because the range of results across an array of models gives a better indication of possible changes in climate than a single model or even an average of models (Barsugli et al.
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153 box (which captures the 25th and 75th percentiles) is almost equally above and below zero.
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154 (and beyond) , there is significant uncertainty about the magnitude.
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155 and relatively drier summers. Note that higher temperatures will increase water evaporation and consumption by vegetation (transpiration)
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156 subcontinental scale; for example, the IPCC reports that sealevel rise in the Northeast may be about 3 inches (0.1 meter) higher than in the Southeast.
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157 Table II.3. Total relative sea-level rise by 2050 (relative to 2010)
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158 Louisiana is projected to subside by about 1 foot (0.3 meter) , whereas Alaska is projected to have uplift of almost 1 foot.
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159 5.1 Introduction The study of impacts of climate change on the U.S. transportation system has emerged as an important area of research in recent years (Committee for Study on Transportation Research Programs to Address Energy and Climate Change 2009)
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160 agencies can better protect their most vulnerable infrastructure and reduce the risk of system failure, with its impact on human life and economic activity. This section reviews the range of climate impacts on infrastructure and operations/maintenance activities that may require the use of adaptation strategies.
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Table II.5. Summary of climate change impacts on the highway system.
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162 Climac/ Weather Change Impact to Infrastructure Impact to Operaons/Maintenance Increased intense precipitaon, other change in storm intensity (except hurricanes) Heavy winter rain with accompanying mudslides can damage roads (washouts and undercung)
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163 affect highway operations and maintenance in several ways. The first is the probable limit on construction activities and the number of hours road crews can work due to health and safety concerns for highway workers (Karl et al.
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164 costs, lessen adverse environmental impacts from the use of salt and chemicals on roads and bridges, extend the construction season, and improve the mobility and safety of passenger and freight travel through reduced winter hazards (Karl et al.
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165 months are likely to increase the flood damage to tunnels, culverts, and coastal highways (CNRA 2009)
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167 "Safety: Make safety a critical component in the development, implementation, operation and maintenance of the transportation system: • Develop contingency plans for a wide variety of climate impacts to be implemented as data/information becomes available; • Utilize information technology to inform stakeholders during times of emergency; • Educate the public and other stakeholders on the threats posed by climate change and fluvial erosion hazards; • Increase inspection of infrastructure if warranted by climate change indicators; "Planning: Optimize the movement of people and goods through corridor management, environmental stewardship, balanced modal alternatives, and sustainable financing: • Apply a decision-making framework to incorporate cost–benefit analyses into adaptive plans and policy; • Increase adaptive capacity among stakeholders so that adaptive planning can be quickly implemented upon realization of risk; "Environmental Stewardship: Build, operate, and manage transportation assets in an environmentally responsible manner: • Work to protect essential ecosystem functions that mitigate the risks associated with climate change; • Educate individuals within the agency to use best practices during recovery periods to avoid ecological damage that may further exacerbate risk; • Recognize the interconnected nature of our built environment with ecological processes. "Preservation: Protect the state's investment in its transportation system.
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168 (e.g., regional planning, programming, and project planning) (Caltrans 2012)
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169 Infrastructure Retrofit Some plans show an awareness of the need to integrate planning policy into the decision to retrofit, rather than approaching the issue from a purely engineering perspective. For instance, the Maryland plan identifies several engineering strategies for retrofitting coastal infrastructure to protect against sea-level rise, such as structural bulkheads, seawalls, or revetments.
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170 of adaptation strategies an individual transportation agency might consider: • Replacing or rehabilitating bridges in order to improve floodwaters conveyance and to avoid scour during high flows • Using pervious pavement and other low-impact development methodologies to manage stormwater through reduced runoff and on-site flow control • Modifying existing seawalls to avoid failures in transportation facilities • Evaluating roadways to minimize their vulnerability to potential risk from landslides, erosion, or other failure triggers • Developing new strategies to effectively respond to increasingly intense storms, including providing alternative transportation access • Managing construction and operations to minimize effects of seasonal weather extremes • Identifying opportunities to incorporate habitat improvements that buffer the effects of climate change on ecosystem health into project designs. 5.4.2 International Adaptation Strategies Of the international reports reviewed, only three provided strategies for dealing with climate change impacts to roadway networks.
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171 Scotland The Scottish Road Network Climate Change Study also emphasizes this point in its discussion of the impacts of predicted climate change factors on the road network. The impact of heat on roadway rutting is frequently mentioned as a climate change concern.
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172 impacts are wide ranging, as are the types of adaptation strategies that can be considered. As shown in the Vermont case, and indeed in examples from other states, climate change and extreme weather events can be considered in many of the traditional agency functions -- planning, environmental analysis, design, infrastructure retrofit, construction, operations, maintenance, emergency response and public outreach and communications.
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173 6.1 Introduction Most agencies that are concerned about adaptation begin by conducting a risk assessment of existing assets. Most of these risk assessments remain largely qualitative and based on professional judgment.
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174 value, or loss of life)
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175 costs to arrive at a better representation of user costs if there is a failure. Restoration times might be as little as a day or two for temporary flooding where permanent damage is not expected or weeks for assets like tunnels and electronic rail infrastructure that require major restoration efforts.
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176 Most of the risk assessments reported in the literature have primarily focused on the water-related impacts: sea-level rise, flooding, intense tropical storms, and intense precipitation. Threats to evacuation routes have also been assessed in many coastal locations.
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177 changes as an improved understanding of risks develops; and (4) considering adaptation for new projects to increase their resiliency to potential climate impacts.
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178 to the expected increase in sea levels at existing tidal gauges. A state-wide digital elevation model was developed by combining information from four existing digital elevation model databases for the state.
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179 by risk element, that is, discrete elements or areas facing the organization (Commonwealth of Australia 2006)
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180 of failure are traumatic or result in huge economic costs. By considering these factors and the role that assets play in the transportation systems, transportation officials can identify where investment should occur to limit the risk associated with such failure.
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181 7.1 Introduction During the course of this research, the United States experienced several extreme weather events that caused severe disruption to the transportation system and in several cases significant damage (e.g., Superstorm Sandy, Hurricane/Tropical Storm Irene, extreme heat events in the Midwest and Southwest, flooding in the Midwest, and unexpected major snow storms in New England and the Mid-Atlantic)
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182 Strategy or Acon State Pre-event Planning Develop meline of likely agency response acons. Establish clear command and control structure for emergency response; develop lines of authority with other agencies.
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183 Strategy or Acon State During-Event System Management (con nued) Establish corridor DOT staff patrols to monitor road damage.
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184 for their consequences to agency operations. Although transportation agencies have decades of experience in responding to extreme storms, recent years have seen a larger than average number of record weather events that have significantly affected transportation systems, and have placed increasing demands on transportation officials to respond quickly and efficiently.
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185 8.1 Introduction This chapter presents the major conclusions of this research study and recommends research topics that could further climate adaptation practice in the United States. The conclusions focus on the current practice of adaptation planning and likely future characteristics.
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186 U.S. regions are projected to increase in temperature, the amounts will vary by location and season.
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187 however, be an excuse for inaction. Some governments, such as New York City, realize the data shortcomings issue and have put forth alternative approaches (e.g., flexible adaptation pathways)
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188 where future problems might occur. Planning is usually data focused and relies on analysis and evaluation processes to identify the most cost-effective set of strategies that will improve transportation system performance.
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189 as will preliminary and final engineering. Research in the following project development areas deserves attention: 9.
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190 with highway dollars to channel flood river flow away from a downstream bridge. This project would examine different non-transportation strategies that could be used to protect transportation assets.
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191 20. Response strategies for extreme weather events: Data on extreme weather events suggest that the last several decades have seen an increase over historical patterns of such events.
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192 8.3.5 Other Research into the following areas would also be beneficial: 26. Institutional Change and Capacity Building: In many ways, considering adaptation within the planning and project development context requires a very different approach to project development than what has been done previously.
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193 Alfaro, M
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194 Regional, and State Governments. Seattle: University of Washington.
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195 Galbraith, R
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196 globalchange.gov/download/NCAJan11-2013-publicreviewdraftchap25-coastal.pdf. National Oceanic and Atmospheric Administration (NOAA)
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197 U.S. Army Corps of Engineers (USACE)
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198 The projections of temperature and precipitation changes in this research were developed using a tool called "MAGICC/ SCENGEN" (M/S; Wigley 2008)
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199 A P P E N D I X B Projected Climate Changes by Region
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Abbreviations and acronyms used without definitions in TRB publications: A4A Airlines for America AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers MAP-21 Moving Ahead for Progress in the 21st Century Act (2012) NASA National Aeronautics and Space Administration NASAO National Association of State Aviation Officials NCFRP National Cooperative Freight Research Program NCHRP National Cooperative Highway Research Program NHTSA National Highway Traffic Safety Administration NTSB National Transportation Safety Board PHMSA Pipeline and Hazardous Materials Safety Administration RITA Research and Innovative Technology Administration SAE Society of Automotive Engineers SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (2005)
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