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5 Meeting the Challenges A daptation to climate change would be necessary even if drastic mitigation measures were taken immediately to stabilize or even eliminate greenhouse gas (GHG) emissions (IPCC 2007). The effects of such global climate changes as warming temperatures and sea level rise occurring today reflect emissions of GHGs released into the atmosphere over the past century. Because of these long-lasting effects, the actions taken by transportation professionals today have implications for how the trans- portation system will respond to climate change in the near and long terms. The first section of this chapter is organized on the basis of timescales that transportation decision makers must consider in determining how best to adapt to climate change. In the short term (i.e., the next several decades), transportation professionals are likely to have operational responses to changing climate conditions and climate extremes. Operators of transportation systems already react to many climate changes, particu- larly extreme events (e.g., intense precipitation, intense tropical storms) and can rapidly adapt operating and maintenance practices for those cli- mate conditions projected to increase in frequency or intensity. Rehabilitating or retrofitting infrastructure requires a longer time hori- zon because engineers design many infrastructure facilities with long service lives in mind (see Chapter 4), thereby providing fewer opportunities for adapting to changing climate conditions without incurring significant costs. Adapting facilities for climate change may also involve the reevaluation and development of design standardsâa process that typically entails a lengthy research and testing program. Finally, constructing new transportation infrastructure or providing major additions to existing transportation systems requires the longest time horizon. Transportation systems shape land use and development 148
Meeting the Challenges 149 patterns, and in turn, population growth and economic development stimulate demand for new infrastructure facilities to support growth. In both cases, decisions made today about where to locate or expand trans- portation infrastructure establish development patterns that persist for generations and are difficult to change. These decisions should be weighed carefully to ensure that people and businesses are not placed in harmâs way as projected climate changes unfold. Following discussion of these topics, the chapter turns to many cross- cutting issuesâflood insurance; monitoring technologies and new materials; data, models, and decision support tools; and new partnerships and organizational arrangementsâthat can help facilitate adaptation to climate change or bring climate change issues into the decision-making process. The chapter ends with the committeeâs findings. ADAPTATION STRATEGIES Annexes 5-1A through 5-1C summarize a wide range of adaptation mea- sures that can be used to address many of the climate change impacts discussed in Chapter 3 (see Annex 3-1). Potential adaptations are identi- fied for land, marine, and air transportation, respectively, by response category: (a) changes in operations, (b) changes in infrastructure design and materials, and (c) other. No attempt is made to estimate the relative costs or effectiveness of these measures, although such analyses would be necessary to evaluate specific infrastructure investment alternatives. The remainder of this section addresses the key issues and opportunities for adaptation in each response category. Operational Responses The most rapid response to the impacts of climate change is likely to come through changes in transportation operating and maintenance practices.1 Every U.S. transportation provider already experiences the adverse impacts of weather on operations under a diverse range of climate conditions. For example, approximately 75 percent of air travel delays in the National Airspace System are weather related (L. Maurice and M. Gupta, presenta- tion to the committee, Jan. 4, 2007). Slick pavement and adverse weather 1 This section draws heavily on the paper by Lockwood (2006) commissioned for this study.
150 Potential Impacts of Climate Change on U.S. Transportation contribute to nearly one-quarter of all highway crashes and about 7,400 fatalities annually.2 In addition, snow, ice, rain, and fog cause about 15 per- cent of total delays on the nationâs highways (FHWA 2004; NRC 2004b). Weather also causes delays and interruptions in service for railroad and marine transportation.3 Transportation agencies expend considerable resources to address these conditions. For example, snow and ice control accounts for about 40 percent of annual highway operating budgets in snowbelt states (FHWA 2006a). Hurricane response is a major focus of transportation operations in states bordering the Gulf Coast. Collaboration between departments of transportation (DOTs) and emergency response personnel has improved, particularly in those areas of the country subject to recurring natural disastersâthe Gulf Coast (hurricanes) and California (earthquakes and wildfires)âbut still has a long way to go. Climate change is altering the frequency, intensity, and incidence of weather events. Changes in Frequency of Extreme Weather Events With changes in the frequency of extreme weather events, operational responses treated today on an ad hoc, emergency basis are likely to become part of mainstream operations. One could imagine, for example, that if strong (Category 4 and 5) hurricanes increased in frequency as is likely, widespread establishment of evacuation routes and use of contraflow operations4 in affected areas might become as commonplace as snow emergency routes in the Northeast and Midwest. Mainstreaming such responses will require expanding the scope of the traditional operating focus of DOTs on traffic and incident management to include weather management, as well as improved training for operating personnel. Increases in Intensity of Weather Events Climate change is expected to trigger more extreme weather events, such as more intense precipitation, which are likely to produce areawide emergen- 2 Based on averages from 1995â2004 data collected by the National Highway Traffic Safety Administration and analyzed by Mitretek Systems. 3 See, for example, Changnon (2006) on the impacts of weather and climate on American railroading and a report by the Office of the Federal Coordinator for Meteorological Services and Supporting Research on the impacts of weather on surface transportation modes (OFCM 2002). 4 Contraflow involves the reversal of traffic flow on one or more of the inbound lanes and shoulders of roads and highways for use in the outbound direction to increase evacuation capacity in an emergency by using both sides of a roadway.
Meeting the Challenges 151 cies and may require evacuation of areas vulnerable to flooding and storm surge. In the wake of September 11, 2001, and Hurricanes Katrina and Rita, the U.S. Department of Homeland Security has mandated an all-hazards approach to emergency planning and response and encouraged better evacuation planning (DHS 2006). Coordination among state and local emergency managersâthe first responders in an emergencyâhas improved, and emergency operations centers (EOCs) have been estab- lished in many metropolitan areas as command posts that can be activated rapidly in an emergency. Typically, transportation is a support function, but the critical role it plays in emergency response and especially in evac- uationâa role that is likely to become more important as the climate changesâshould be strengthened through increased collaboration between emergency managers and transportation providers and more representa- tion of transportation agencies and private transportation providers at EOCs. Operators of transportation systems also need to work more closely with weather forecasters and emergency response planners to convey their own lead-time requirements for providing the necessary personnel and equipment in an evacuation and protecting their own assets. Finally, a greater emphasis on emergency management as a separate functional responsibility within DOTs and other transportation providers is needed. Regional transportation management centers (TMCs) provide one location through which collaboration between transportation providers and emergency managers can occur (see Box 5-1). TMCs are currently focused on traffic monitoring and incident management through rapid deployment of police, fire and rescue, and emergency medical services. In some metropolitan areas, new functions are being added, such as better weather information and greater use of real-time traffic advisories, as well as links with emergency managers. Some TMCs are also serving as EOCs. However, integration of weather and emergency management functions in TMCs is still in its infancy according to a recent U.S. Department of Transportation assessment (FHWA 2006b). Changes in Incidence of Weather Patterns Climate changes will bring new weather patterns to previously unaffected areas of the United States. These changes, however, may not necessarily require the development of new operating and maintenance strategies. The United States has a diverse climate, ranging from subtropical to arctic
152 Potential Impacts of Climate Change on U.S. Transportation BOX 5-1 Transportation Management Centers Improving the efficiency of the existing highway network involves the appli- cation of technologies, such as intelligent transportation systems (ITS), and control strategies, such as ramp metering, dynamic message signs, and incident management. In many large metropolitan areas, these devel- opments have been accompanied by establishment of regional transportation management centers (TMCs), which are seen as the cockpit or nerve center for monitoring traffic incidents and providing rapid police response, crash clearance, and travel advisories. Many TMCs are manned by staff from mul- tiple agencies and jurisdictions working as a team. Some TMCs are focused primarily on traffic and incident management. Others, such as Houston TranStar, have a broader scope. Opened in 1996, Houston TranStar is a consortium partnership of transportation and emer- gency management agencies in the greater Houston area housing engineers, law enforcement personnel, information technology specialists, and emer- gency managers. In addition to traffic monitoring and incident control, emergency management personnel from the Harris County Office of Emer- gency Management monitor potential emergencies due to severe weather using state-of-the-art technology, such as flood warning monitors, Doppler radar, satellite imagery, and weather data from the National Weather Service, to provide the public with real-time information. The city of Chicago recently opened a new City Incident Center (CIC), which integrates the cityâs homeland security efforts with traffic services, among other activities. CIC follows on the creation of a Traffic Management Authority in 2005, dedicated to improving traffic flow through ITS technol- ogy and centralized control systems. The new facility will have positions dedicated to traffic management but will also provide a central location for communication among dispatch operators from all the relevant city depart- ments so they can respond rapidly and effectively in the event of an emergency (Inside ITS 2006). and from arid to wet, with several regions being subject to temperature extremes and such events as blizzards, hurricanes, tornadoes, floods, wild- fires, avalanches, and mudslides. As climate patterns change, the transfer of best practices from one location to another will be essential. A mecha- nism is needed to encourage such information exchange, involving all
Meeting the Challenges 153 transportation modes. This effort should build on existing technology transfer mechanisms, such as the Technology Implementation Group of the American Association of State Highway and Transportation Officials (AASHTO).5 Design Strategies Operational responses are geared to addressing near-term impacts of climate change. To make decisions today about rehabilitating or retro- fitting transportation facilities, especially those with long design lives (see Table 4-2 in the previous chapter), transportation planners and engineers must consider how climate changes will affect these facilities 50 years or more from now. Adapting to climate change will also require reevaluation, development, and regular updating of design standards that guide infrastructure design. The purpose of design standards is to provide engineers with guidance on how to construct infrastructure for safe and reliable performance.6 These standards represent the uniform application of the best engineering knowledge, developed through years of experimental study and actual experience. Often they become embedded in regulatory requirements and funding programs.7 Design standards embody trade-offs between per- formance (e.g., safety, reliability) and cost. Faced with a myriad of factors that can affect performance, engineers typically select the most demand- ing parameterâthe 100-year storm, the heaviest truck, the most powerful wind speedâas the basis for design, thereby building in a safety margin to minimize the chances of failure. Environmental factors are integral to the design of transportation infrastructure. Conditions such as temperature, freezeâthaw cycles, and duration and intensity of precipitation determine subsurface and founda- 5 The primary objective of AASHTOâs Technology Implementation Group, which grew out of an AASHTO task forceâs successful effort to implement products of the Strategic Highway Research Program, is to provide leadership to state DOTs, local governments, and industry in the selection and promotion of ready-to-implement technologies. 6 This section draws heavily on the paper by Meyer (2006) commissioned for this study. 7 To be eligible for federal funding, for example, state and local governments must comply with federal standards with respect to lane and shoulder widths on highways and bridge clearances over navigable waterways. If the infrastructure is damaged or destroyed, federal agencies and insurers typically allow renovation or rebuilding only to replacement standards; upgrading is not a reimbursable cost.
154 Potential Impacts of Climate Change on U.S. Transportation tion designs, choices of materials, and drainage capacity. The issue is whether current design standards are adequate to accommodate the cli- mate changes projected by scientists. Table 5-1 provides an assessment by Meyer (2006) of the principal climate-induced changes and their implica- tions for infrastructure design in both the short and long terms. Looking across all climate changes, the author notes that the most dominant impact is on those design elements most associated with forces resulting from water flows. This finding is not surprising in view of the extensive damage to transportation infrastructure and buildings caused by flooding and storm surge in Hurricanes Katrina and Rita. Climate changes, however, will not affect the design of all infrastructure modes equally, a second important observation. For example, wave action is more critical than temperature changes for coastal bridge design. Finally, climate extremes, such as stronger wind speeds, increased storm surges, and greater wave heights, will place the greatest demands on infrastructure because they are likely to push the limits of the performance range for which facilities were designed. How should engineering design decisions be modified to address cli- mate change, particularly for longer-lived infrastructure for which the uncertainties are greater regarding the magnitude and timing of climate changes? One option is to build to a more robust standard, assuming a greater frequency and magnitude of extreme events, without a full under- standing of future risks and presumably at greater cost. This strategy could be appropriate for major facilities in vulnerable locations (e.g., critical bridges and evacuation routes), but its high costs necessitate a highly selective approach. Another option is to upgrade parallel routes, but this alternative depends on the availability of right-of-way and the cost of upgrading. A third option is to build infrastructure with shorter design lives, presumably at lower cost, to be retrofitted as more knowledge about future climate conditions is gained. This alternative probably is not viable in the United States because of the disruption and negative public reaction resulting from more frequent retrofits of major facilities. Most states are adopting a âfast in, fast out, and stay outâ approach to major reconstruc- tion projects. A final option is to hedge by building to current standards or making marginal improvements, recognizing that the infrastructure remains at risk and may require major improvements in the future. This alternative poses many of the same problems as the previous one. All four options involve important costârisk reduction trade-offs that engineers
TABLE 5-1 Climate-Induced Changes That Could Influence Transportation Infrastructure Design Climate-Change Changes in Phenomenon Environmental Condition Design Implications Temperature Rising maximum Over the short term,a minimal impact on change temperature; lower pavement or structural design; potential minimum tem- significant impact on road, bridge scour, and perature; wider culvert design in cold regions temperature range; Over the long term, possible significant impact on possible significant pavement and structural design; need for new impact on permafrost materials and better maintenance strategies Changing Worst-case scenario, Over the short term, could affect pavement and precipitation more precipitation; drainage design; need for greater attention to levels higher water tables; foundation conditions, more probabilistic greater levels of approaches to design floods, more targeted flooding; higher maintenance moisture content Over the long term, definite impact on foundation in soils design and design of drainage systems and culverts; impact on design of pavement subgrade and materials Wind loads Stronger wind speeds Over the short term, design factors for design and thus loads on wind speed might change; wind tunnel bridge structures; testing will have to consider more turbulent more turbulence wind conditions Over the long term, need for materials of greater strength; impact on design considerations for suspended and cable-stayed bridges Sea level rise Rising water levels in Over the long term, greater inundation of coastal coastal areas and areas; need for more stringent design stan- rivers; increases in dards for flooding and building in saturated severe coastal soils; greater protection of infrastructure flooding needed when higher sea levels combine with storm surges Greater storm Larger and more fre- Over the short term, need for design changes to surges and quent storm surges; bridge height in vulnerable areas; need for wave heights more powerful wave more probabilistic approach to predicting action storm surges Over the long term, need for changes to bridge design, both superstructure and founda- tions; changes in materials specifications; and more protective strategies for critical components a For purposes of this table, short term is defined as the next 30 to 40 years; long term is from 40 to 100 years. Source: Meyer 2006, Table 1.
156 Potential Impacts of Climate Change on U.S. Transportation and planners can best address through a more strategic, risk-based approach to design and investment decisions, such as that described in the previous chapter. The approach taken by Transit New Zealand to deter- mine the necessity and feasibility of taking action now to protect the state highway network from the potential future impacts of climate change could also be instructive (see Box 5-2). More fundamentally, the scientific community and professional associ- ations must reevaluate design standards for transportation infrastructure that take climate change into account and begin the lengthy process of developing new standards where appropriate. Reexamination of design standards can be prompted by a single event, such as the damage to coastal highway bridges from Hurricane Katrina, when it became evident that the current state of practiceâdesigning bridges for a riverine environment and a 50-year stormâwas inadequate. The Federal Highway Admin- istration (FHWA) not only approved and shared in the cost of rebuilding the damaged bridges to a higher design standard but also recommended the development of more appropriate bridge design standards in general for a coastal environment that would take into account the combined effects of storm surge and wave action and assume a more severe storm event (e.g., a 100-year or even 500-year storm) (FHWA 2005a).8 Typically, however, the development of design standards follows a time-consuming and systematic process that involves professional organi- zations in an extensive research and testing program over a period of decades. Once the standards are in place, engineers are understandably reluctant to change them. A combination of the length of time required to modify or develop new standards, the institutional procedures for approval of standards (vetting any changes through professional committees of practicing engineers), and the use of well-established standards as evi- dence of âgood practiceâ in litigation leads to a conservative approach to change. Developing standards to address climate change in a timely manner thus will require leadership by the scientific community and professional associations and, given the scope of potential impacts, a broad-based, federally sponsored research program that must begin soon. A good model is the congressionally mandated National Earthquake 8 AASHTO and state DOTs are leading this initiative, and research on wave forces and wave load design practices is now being undertaken by universities and the U.S. Department of Transportationâs TurnerâFairbank Highway Research Center, among others.
Meeting the Challenges 157 BOX 5-2 Climate Change and Asset Management: New Zealand Transitâs Approach to Addressing Impacts of Climate Change Under the 2004 Resource Management (Energy and Climate Change) Amendment ActâNew Zealandâs principal legislation for environmental managementâTransit New Zealand was required to take into account the effects of climate change as it plans, constructs, and maintains the state highway network (Kinsella and McGuire 2005). The key climate changes of concern to state highways are sea level rise, coastal storm surges, and increased frequency and intensity of heavy rainfall events. The primary assets at risk are bridges, culverts, causeways and coastal roads, pavement sur- faces, surface drainage, and hillside slopes. Transit New Zealand proceeded with a two-stage assessment to identify those areas requiring action. Stage 1 involved assessing the need to act now to manage future potential impacts of climate change. Three criteria were used: â¢ Level of certainty that the climate change impact will occur at the magnitude predicted in the specified time frame, â¢ Intended design life of the state highway asset, and â¢ Capacity of the agencyâs current asset management practice to man- age the impact. The results of the Stage 1 assessment revealed that current asset manage- ment practice is generally adequate to deal with impacts of climate change for most of the network, but that bridges and culverts with an intended design life of more than 25 years may require case-by-case consideration to ensure protection (Kinsella and McGuire 2005). Stage 2 involved assessing the economic feasibility of acting now to man- age future potential impacts of climate change and was focused on bridges and culverts with design lives of greater than 25 years. Making several sim- plifying assumptions, the analysis examined three options: (a) doing nothing, (b) retrofitting all existing bridges and culverts now to avoid future climate change impacts, and (c) designing all new bridges and culverts to accommo- date future climate changes to 2080. The analysis revealed that it would not be economical to retrofit the existing stock of bridges and culverts, but it (continued)
158 Potential Impacts of Climate Change on U.S. Transportation BOX 5-2 (continued) Climate Change and Asset Management: New Zealand Transitâs Approach to Addressing Impacts of Climate Change would be preferable to repair the assets when a specific loss or need became evident. The primary reasons for this conclusion were uncertainties about where and when the impacts of climate change will manifest themselves and the historical number of bridges and culverts lost prematurely because of other events. Retrofitting all new bridges and culverts to take climate change into account was also determined not to be economical. Nevertheless, the agency decided that, where possible, provision should be made for subse- quent retrofitting (either lifting or lengthening the bridge) in the event impacts are experienced. For major bridges (and culverts) where retrofitting is not practical, the structure should be designed for projected future impacts of cli- mate change on the basis of the best available information (Kinsella and McGuire 2005). Transit New Zealand has amended its Bridge Manual to include consid- eration of relevant impacts of climate change as a design factor. In addition, the agency will continue to monitor climate change data and developments and review its policy when appropriate. Hazard Reduction Program, begun in 1977, which has provided much of the underlying research for seismic standards (see Box 5-3). New Infrastructure Investment, Transportation Planning, and Controls on Land Use One of the most effective strategies for reducing the risks of climate change is to avoid placing people and infrastructure in vulnerable locations, such as coastal areas. Chapter 3 described the continuing development pressures on coastal counties despite the increased risk of flooding and damage from storm surge and wave action accompanying projected rising sea levels. Many areas along the Atlantic, Gulf, and Pacific coasts will be affected. Once in place, settlement patterns and supporting infrastructure are difficult to change. In New York City, for example, a major concern of emergency planners is handling the evacuation of some 2.3 million New Yorkers from flood-prone areas in the event of a Category 3 or greater hurricane (New York City Transit 2007). Continued development of such vulnerable areas
Meeting the Challenges 159 BOX 5-3 Development of Seismic Standards in the United States In 1977 Congress passed the Earthquake Hazards Reduction Act, which established the National Earthquake Hazard Reduction Program (NEHRP)â a long-term earthquake risk reduction program. Member agencies include the United States Geological Survey, the National Science Foundation, the Federal Emergency Management Agency, and the National Institute of Standards and Technologyâagencies engaged primarily in research and development. The mission of NEHRP is broad and includes understanding the science of earthquakes and their effects, improving earthquake hazard identification and risk assessment methods, and developing effective prac- tices (e.g., model building codes) and policies to reduce earthquake losses (NEHRP 2007). One of the primary accomplishments of NEHRP has been the develop- ment of design standards for the seismic safety of buildings, both new and existing, which serve as a basis for national model building codes. Seismic standards and guidelines have also been developed for lifelinesâ telecommunications, transportation, water, sewage, electric power, gas, and liquid fuel lines. Adoption of the standards is voluntary, but some states, such as California, have incorporated the model national codes into state regulations, and the federal government has adopted the standards for its own buildings and as a prerequisite for obtaining federal funds. FHWA, for example, requires that federally assisted bridge and highway projects meet minimum seismic standards. The development of seismic specifications for bridges began in the 1970s with the San Fernando earthquake and was spurred by the occurrence of sub- sequent major earthquakes. For example, the 1989 Loma Prieta earthquake led the American Association of State Highway and Transportation Officials to adopt a standard seismic specification for bridges in 1990. In response to the limitations of a âone-size-fits-allâ approach, a modified performance- based standard was proposed in 1997, but it was rejected as being too complex and having too high a return frequency (2,500 years) relative to other hazards (Buckle 2006). (A performance-based national consensus standard has been developed for buildings.) Nevertheless, revisions are under way, and the performance-based approach, which takes into account different performance requirements and levels of risk, could be a model for the development of standards to address the impacts of climate change. A program such as NEHRP would be essential to fund the necessary support- ing research and testing.
160 Potential Impacts of Climate Change on U.S. Transportation will only place more communities and businesses at risk and increase the difficulty of evacuation in the event of a major storm. Why do transportation planners fail to consider development patterns in making investment decisions? The short answer is that they do, but not from the perspective of land use control. Public-sector transportation planners typically forecast expected land use patterns over a 25- to 30-year period as the basis for modeling future travel demand and infrastructure investment needs (Meyer and Miller 2001). However, they rarely consider whether such investments are desirable, or what development may result from building or expanding transportation networks (Amekudzi and Meyer 2005).9 Although the long-term capital improvement and budgeting process is different in the private sector (see Chapter 4), it suffers from the same limitations. One of the main reasons for the disconnect between transportation investment decisions and land use and development deci- sions can be traced to governance arrangements. Decisions concerning large-scale transportation infrastructure investments are the responsibility of states, regional authorities, and the private sector. Local governments and a few states (e.g., Florida, California) control land use decisions through comprehensive plans, zoning ordinances, permitting, and building codes. Locally controlled land use planning, the typical situation in the United States, has too limited a perspective to account for the broadly shared risks of climate change. Local governments are interested primarily in the jobs and economic development that growth may bring to their communities, although in many localities, the costs of uncontrolled growth in terms of crowded roads and schools are being recognized. In some locations, greater integration of transportation and land use planning is resulting from smart growth policies, which recognize the impact of transportation investments on regional development and economic growth and vice versa; such inte- gration is not common, however. Transportation planners cannot resolve these issues single-handedly. The developers of any strategy that involves imposing land use controls to address climate change would need to build consensus among key deci- sion makers in both transportation and land use, probably at the regional levelâa challenging proposition. Nevertheless, if transportation planners 9 Meyer (2006) notes two locationsâLake Tahoe, Nevada, and Cape Cod, Massachusettsâwhere transportation planners have identified environmentally sensitive areas that are off limits to new infrastructure and development, but these are the exceptions rather than the rule.
Meeting the Challenges 161 were required to work more closely with land use planners and consider potential impacts of climate change in the development of long-term invest- ment plans, the issues would become more visible. At present, the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) encourages greater collab- oration and partnership among transportation planners and state and local agencies responsible for land use management, among others, in plan development.10 In the reauthorization of this legislation, such collabora- tion should be required, as should consideration of climate change impacts and their effects on infrastructure plans and investments, particularly in vulnerable locations. At the local level, some metropolitan planning organizations (MPOs) have already begun to adopt more flexible, scenario-based approaches in developing their long-range transportation investment plans (see Box 5-4). The impetus has come in part from the desire to provide local communities with a framework within which to better understand the impacts of growth and the difficult trade-offs among social, economic, and environmental goals in planning future transportation investments. Use of geographic information systems and modeling has enabled planners to illustrate and quantify the impacts of a range of regional growth scenarios on land use and area traffic, among other factors. At the end of the planning process, one sce- nario typically is selected as the preferred option. Development and monitoring of performance measures enable local planners to examine the effects of their choices and revisit the plans periodically to take into account new developments and changes in local priorities. Scenario planning could be adapted to take potential climate changes into account in the development of future regional transportation plans. For example, projections of current development patterns and supporting transportation infrastructure, when overlaid on maps showing current ele- vations and expected sea level rise, could illustrate the increased risks of allowing uncontrolled development in vulnerable coastal areas and the desirability of managed growth policies and protection of critical infra- structure. Climate scientists, perhaps at local universities, could assist in the 10 More specifically, Section 6001 and the Final Rule on Statewide and Metropolitan Transportation Planning (Federal Register 2007) require that long-range transportation plans be developed in consultation with agencies responsible for land use management, natural resources, environmental protection, conservation, and historic preservation, and that state conservation plans or maps and inventories of natural or historic resources be consulted.
162 Potential Impacts of Climate Change on U.S. Transportation BOX 5-4 Scenario Analysis in Transportation Planning Scenario analysis as practiced by transportation planners is a process through which public agencies, private entities, and citizens work together to envi- sion the long-term future of their communities (FHWA 2005b). Scenario planning starts with a business-as-usual baseline scenario, incorporating cur- rent plans or trends for a region. Then, a range of alternative future scenarios is identified on the basis of community input, through the use of tools and transportation models incorporating geographic information to identify im- pacts both quantitatively and visually. Typically, one scenario is chosen as the preferred alternative and is adopted as the regionâs vision for the future. According to a recent survey, MPOs are the lead sponsors of scenario plan- ning, followed by nonprofit organizations (e.g., environmental groups) and local governments (Bartholomew 2005). Numerous localitiesâSalt Lake City, Houston, Sacramento, Portland, Los Angeles, and Chicago, among othersâhave adopted this approach. The recently released 2035 Regional Transportation Plan for Greater Houston is a good example of the use of scenarios to examine the impacts of different land development choices on travel congestion, transit use, and population growth in floodplains and hurricane evacuation zones (Houstonâ Galveston Area Council 2007). Facing a projected 75 percent increase in population and a 60 percent increase in employment over the next 30 years, the council of governments for the greater Houston areaâthe Houstonâ Galveston Area Councilâspearheaded the Envision Houston Region initiative in 2005 to engage elected officials, residents, and other stakeholders in planning and creating a long-term growth strategy to 2035. Four scenarios were considered, ranging from the status quo to a scenario assuming high- density mixed-use development along transit corridors and town centers; the latter is the selected Envision scenario, which planners believe offers a rea- sonable path forward and has considerable community support. The regional plan also is notable for taking the first steps toward integrat- ing climate change into the transportation planning process. The planners noted the vulnerability of the region to tropical storms and flooding, likely to be intensified by climate change and land subsidence, and the scenarios considered compared population growth in sensitive floodplains and hurri- cane evacuation areas. The chosen Envision scenario showed a reduction in population in both areas, alleviating demand on evacuation routes as com- pared with the baseline, status quo scenario.
Meeting the Challenges 163 planning process by identifying plausible impact scenarios. University of Washington climate scientists, for example, developed projections of sea level rise for Seattle that became a consideration in designing a major reha- bilitation of the Alaskan Way Seawall.11 In those major metropolitan areas highly vulnerable to the impacts of climate change, where projected sea level rise combined with storm surge could threaten already densely developed areasâparts of New York City, Miami, and San Francisco, for exampleâoptions such as levees and storm barrier systems are likely to be considered to protect valuable real estate. These options are costly, they can create environmental problems, and they may provide a false sense of security.12 Moreover, as was the experi- ence in New Orleans, levees can encourage development in âprotectedâ flood risk areas (ASFPM 2007). In small communities, exposure to impacts of climate change may necessitate abandoning homes, businesses, and infrastructure and relocating inland. For example, reduced sea ice along Alaskaâs Arctic coast is already eroding shoreline and exposing coastal areas to the action of winter storm surges and waves, a pattern that will be exac- erbated by further sea level rise. Some 200 Native American villages are at risk and may soon be abandoned for inland locations (ACIA 2004). CROSSCUTTING ISSUES Flood Insurance Private insurers may be able to accomplish what government cannot in terms of land use control. Some major insurers, for example, are refusing to write new or renew existing homeownersâ policies in areas already vul- nerable to hurricanes and other severe storms, which are likely to intensify in a warming climate (Adams 2006). Florida, Texas, Louisiana, Mississippi, Hawaii, New York City, and Long Island are among the affected areas thus 11 Sea level projections from the climate impacts research group at the University of Washington suggested that the cityâs current design standards for the new seawall did not adequately account for the potential projected rise in sea level. Given the magnitude of the long-term financial and transportation impacts of the Alaskan Way Seawall project, the City Auditorâs Office recommended that the city obtain a comprehensive, independent analysis that would consider all available scientific sources in estimating the probabilities of expected increases in sea level and their rate (Soo Hoo and Sumitani 2005). 12 Levees interfere with the natural attenuation of flows from floodwaters, cause backwaters, generally increase the depth and velocity of floodwaters, and encourage channel degradation and eventual bank erosion (ASFPM 2007).
164 Potential Impacts of Climate Change on U.S. Transportation far. Some states, such as Florida, have stepped up to become insurers of last resort for coastal homes and businesses, but the high costs of providing coverage are unlikely to be sustainable or would result in prohibitive pre- mium increases in many cases if the costs were passed on to homeowners. Moreover, the provision of insurance in hazard-prone areas that is not actuarially sound is bad public policy. The federal government is already the insurer of last resort for home- owners and businesses that cannot secure affordable private flood insurance in flood hazard areas. In 1968 Congress authorized the National Flood Insurance Program (NFIP) to mitigate increasing taxpayer-funded flood relief. The Federal Emergency Management Agency (FEMA) admin- isters the program and maps the nationâs floodplains; these maps serve as the basis for determining the eligibility of homeowners and businesses for NFIP funding. To become eligible, a community must adopt and enforce floodplain management ordinances and building code requirements to reduce future flood damage.13 In exchange, NFIP makes federally backed, affordable flood insurance available to homeowners, renters, and busi- nesses in mapped Special Flood Hazard Areas (SFHAs) through licensed agents and insurance companies. Flood insurance is required to secure financing for buying, building, or improving a structure in SFHAs. New buildings must be elevated to or above the predicted 100-year flood level, and foundations must be designed to resist flood loads (Elliott 2005). Buildings that are repaired or improved after floods must be brought into compliance with these ordinances if the repair costs 50 percent or more of the market value of the structure. Over the years, NFIP has been criticized for encouraging more devel- opment in these flood-prone areas than would have occurred without the program (Elliott 2005; Burby 2006). Others suggest that the program has had little impact because many properties (e.g., beach houses) are pur- chased without a mortgage and thus need not comply with floodplain ordinances. Communities have also been slow to enact and enforce flood- plain management measures. Finally, flood insurance is not required of properties located behind levees that have been certified for 100-year storms, even though such properties are at enhanced risk for any flood that exceeds the 100-year storm. Because climate change is projected to 13 Details of the program were accessed from the FEMA website at www.fema.gov/about/programs/ nfip.shtm on May 9, 2007.
Meeting the Challenges 165 trigger more intense storms and sea level rise will extend the areas of flood damage in some SFHAs, FEMA and congressional oversight com- mittees should reevaluate the risk reduction effectiveness of the program. FEMA is engaged in a multiyear map modernization program to pro- vide reliable digital flood hazard data and maps in support of NFIP. However, the maps are based on historical data and thus do not take account of climate change. The SFHA boundaries are keyed to the 100-year storm, the base elevation data are inadequate (NRC 2007), and the pace of updating is slow. In fact, some states have taken over the task of updating to speed up the process. Further additions to flood zone maps may be needed and are particularly important to transportation engineers because these maps have become a quasiâdesign standard for determining appro- priate drainage capacity, for example, for transportation infrastructure in coastal areas. Monitoring Technologies and New Materials Better monitoring technologies and new materials could offer engineers alternatives to costly infrastructure retrofit or replacement in advance of climate change. For example, better systems for monitoring impacts of climate change on infrastructure could provide engineers with an early warning of problems, buying time for making the necessary modifications. This approach would also provide a good solution for less critical infra- structure facilities for which the costs of retrofitting in anticipation of climate change are not economical. In Alaska, where climate warming is occurring more rapidly than in the lower 48 states, engineers are closely monitoring bridge foundations for scour. Hotter, dryer summers have led to increased glacial melting and longer periods of high stream flows, lead- ing to both increased sediment transport on rivers and scour at bridge crossings. A network of sonars has been installed on several scour-critical bridges around the state. The monitoring data are sent regularly to the Alaska Department of Transportation and Public Facilities (J. Conaway, United States Geological Survey, personal communication, March 8, 2006), an approach that could be adapted for use in other states.14 Sensors and other âsmartâ technologies yet to be developed could also be used more widely to monitor changing climate conditions and issue 14The FHWA scour program requires bridge owners to evaluate bridges for potential scour associated with the 100-year storm and a 500-year superflood event (FHWA 2005a).
166 Potential Impacts of Climate Change on U.S. Transportation warnings when thresholds are exceeded. Sensors are already available that monitor changing pressures on a building or bridge and issue a warning when the pressures become abnormal (Meyer 2006). Sensors could also be embedded in pavements and bridge decks, for example, to monitor stress and strain as temperatures change, enabling remedial action to be taken before failure occurs. The collapse of the Minneapolis Interstate 35W bridge in August 2007 brought renewed attention to the need for better technolo- gies to monitor bridge conditions. Numerous technologies are available: X-ray machines can spot hidden cracks in girders, computerized monitors can track minute changes in stresses on steel beams, and sensors embedded in concrete can track corrosion of steel reinforcing beams. The costs are not smallâone estimate to install monitoring equipment on a large bridge was $250,000âbut relative to retrofitting or replacing a failed structure, the costs are marginal (Inside ITS 2007). Advances in material sciences (appli- cations of nanotechnologies),15 computer processing, and communications capabilities, as well as in sensor technologies, could provide a fertile field for the development of devices for monitoring climate changes and communi- cating the results to the appropriate infrastructure owners. New materials also hold promise for addressing some climate changes. For example, temperature extremes, particularly increases in very hot days and heat waves, are likely to affect both pavements and rails. Changnon et al. (1996) report that highways and railroads were damaged by heat- induced heaving and buckling of joints during the 1995 heat wave in Chicago. Extreme heat can also cause misalignment of rail lines and derail- ments, although the use of continuous welded rail should prevent kinks from occurring (Changnon 2006). Continued research and development of materials that can withstand high temperatures would be productive, as would effective mechanisms for sharing new knowledge. Data, Models, and Decision Support Tools Data systems for monitoring the impacts of climate change can be an effective tool for determining appropriate adaptation strategies. One such system is the Alaska Engineering Design Information System (AEDIS), described in Chapter 3. AEDIS provides geographic-specific data on tem- 15Nanotechnology is a field of applied science focused on control of matter on a scale smaller than 1 micrometer, normally 1 to 100 nanometers, as well as the fabrication of devices on this same scale.
Meeting the Challenges 167 peratures, precipitation levels, permafrost, and snow depth collected from weather stations located around the state. The data are intended to help in deriving engineering design parameters (e.g., load-bearing capac- ity), scheduling maintenance and repairs, and selecting optimum locations for transportation infrastructure (T. Douglas, Cold Regions Research and Engineering Laboratory, personal communication, March 9, 2006). As trend data accumulate, AEDIS could provide a useful repos- itory of information on the longer-term impacts of climate change on infrastructure that could be linked with a database of response strategies and costsâfrom changes in maintenance practices, to use of new mate- rials, to design changes. Improving information on weather for transportation infrastructure applications is another important area for development, particularly in view of the potential for more climate extremes. The national needs assessment report of the Weather Information for Surface Transportation initiative (OFCM 2002)âa joint effort of the National Oceanic and Atmospheric Administration (NOAA) and FHWAâidentifies as a par- ticular need more accurate information at higher spatial (e.g., surface temperatures) and temporal resolutions (OFCM 2002). The information must also be provided with sufficient lead time (for forecasts) and cur- rency (for observations) to guide operational decisions. Providing the data will require improved weather detection and forecasting; better understanding of thresholds for precipitation, temperature, winds, and the like, which affect transportation operations and, if exceeded, could cause significant interruptions in operations or infrastructure failure; and improvements in data integration and real-time communication to both transportation operators and system users (Lockwood 2006). Clarus, a major initiative of FHWAâs Surface Transportation Weather Program,16 is already working to develop and demonstrate an integrated nationwide surface weather observing, forecasting, and data management system. A range of observational technologies, from remote to fixed sensors to vehi- cle probes, are being tested as sources of real-time data, as is a suite of tools to make use of the data. Such efforts could have application for other transportation modes. 16 The Surface Transportation Weather Program was authorized in SAFETEA-LU for $5 million annually for 4 years. The primary focus is on alleviating the impacts of adverse weather on the safety and reliability of the nationâs highways.
168 Potential Impacts of Climate Change on U.S. Transportation The 2004 and 2005 hurricane seasons provided a vivid illustration of the need for improvements in modeling of the effects of storm surge and wave action, which will be aggravated by sea level rise. NOAAâs Sea, Lake, and Overland Surge from Hurricanes model and, more recently, the Advanced Circulation Model (ADCIRC) (described in Chapter 2) have been used to estimate the threat from storm surge.17 These models use historical input data that are infrequently updated. For example, when ADCIRC was run with input data through the 2005 hurricane sea- son, it was found that the magnitude of the 100-year storm-surge flood would now reoccur at an interval of 75 years. After Hurricane Katrina, con- siderable research was also conducted on wave action on bridges (J. Krolak, briefing, Wave Force Symposium, TurnerâFairbank Highway Research Center, July 27, 2006); the results of this research should help in revising coastal bridge design standards. If extreme weather events require evacuation of affected areas, better modeling to support evacuation efforts will be needed. Some MPOs are using travel demand models to estimate the time required to evacuate regional areas for different types of emergencies, but this is not common practice. For example, according to modeling estimates provided after Hurricane Rita by the HoustonâGalveston Area Council, the council of gov- ernments for the Houston metropolitan area, it would take 80 to 120 hours to evacuate 3 million residents from Galveston, Houston, and other coastal areas, assuming use of contraflow and optimum flow conditions. The nec- essary lead time far exceeds the ability of meteorologists to predict the landfall and trajectory of hurricanes (HoustonâGalveston Area Council 2007), and this has led local governments to consider hardening public facilities on higher ground and encouraging residents in nonvulnerable coastal areas to shelter in place. Simulation models are also being used to help identify optimal evacuation routes, compute estimated evacuation times, and determine traffic management needs for an emergency planning area (Goldblatt and Weinisch 2005). However, these models must be upgraded to provide more real-time information to assist emergency man- 17 ADCIRC is being applied in southern Louisiana by the U.S. Army Corps of Engineers New Orleans District to design levee heights and alignments, by FEMA to establish flooding probabilities for insurance purposes, by the State of Louisiana at the Center for the Study of Public Health Impacts of Hurricanes to operationally predict hurricane inundation, and by the Louisiana State Department of Natural Resources to assess coastal restoration projects (information from the ADCIRC website, accessed at www.adcirc.org on October 10, 2007).
Meeting the Challenges 169 agers and transportation providers in responding to an incident (e.g., by changing routing instructions and notifying emergency response teams). New Partnerships and Organizational Arrangements Adapting successfully to climate change will require forging new partner- ships and organizational arrangements that better align with the impacts of climate change, which do not follow modal, jurisdictional, or corporate boundaries. As discussed earlier, decision making in the transportation sector is structured around these boundaries. Transportation planning is conducted primarily at the regional level, often in a bottom-up process that starts with local jurisdictions. Railroads, trucking, and waterborne commerce are largely private enterprises with varying levels of federal participation. Partnerships could involve closer collaboration between transportation agencies and emergency responders. Tabletop exercises, for example, in which emergency managers and critical transportation agencies, among others, role play their responses to hypothetical emergency situations (e.g., a terrorist attack, a major hurricane), provide an opportunity for such coor- dination and contact. Other relevant partnerships could involve local collaboration between university climate scientists and regional transporta- tion planners; greater interaction between transportation planners and those who control land use (both described previously); and creation of a more formal process for better communication among transportation pro- fessionals, climate scientists, and other relevant scientific disciplines, along with a repository for transportation-relevant climate change information. The creation of regional and multistate organizational arrangements to address climate change is a formidable challenge but could yield enormous payoffs in the ability to respond not only to climate change but also to other natural and man-made disasters (e.g., earthquakes, terrorist inci- dents). The transportation sector has some models for cross-jurisdictional arrangements, such as regional authorities for specific facilities (e.g., the Alameda Corridor in California).18 Regional and multistate emergency 18 Created as a Joint Powers Authority by affected cities, the Ports of Los Angeles and Long Beach, and the Los Angeles County Metropolitan Transportation Authority, the Alameda Corridor Transportation Authority guided the development of a 20-mile-long rail cargo expressway. The expressway separates freight rail from street traffic and passenger trains while linking the ports to the transcontinental rail network near downtown Los Angeles.
170 Potential Impacts of Climate Change on U.S. Transportation response operations that include transportation are beginning to emerge in the wake of hurricanes and other disasters, such as the events of September 11, 2001. These might serve as the nucleus for multistate regional compacts to address other issues, such as the impacts of climate change (Deen 2006). State-mandated regional compacts for addressing regional air quality issues offer another model.19 One could imagine the emergence of similar arrangements to address such problems as the impact of sea level rise on coastal real estate and infrastructure in the tristate New York area or other coastal areas, the effects of drought on shipping along inland waterways, or the impact of hurricanes in the Gulf Coast region. The development of organizational arrangements âright-sizedâ to address the problems for transportation infrastructure created by cli- mate change may require state or federal action. The California Coastal Commission is a good example of a state initiative designed to resolve a regional problem. In the early 1970s, many Californians became alarmed that private development was cutting off public access to the shore and by voter initiative petitioned the state to exert its stewardship role to protect coastal assets for future generations. In 1976 the state legislature enacted the California Coastal Act and established a permanent California Coastal Commission, which plans and regulates development and use of natural resources along the coast in partnership with local governments and in keeping with the requirements of the Coastal Act (California Coastal Commission 2007). One could imagine a similar arrangement to mediate land use and development issues in vulnerable coastal areas in light of projected climate changes. FINDINGS Adaptation is unavoidable to address the impacts of climate change due to GHG emissions released into the atmosphere decades ago or longer. The prudent strategy is for transportation professionals to begin now to take a 19In the eastern half of the United States, for example, where regional ozone is an important concern, organizations such as the Ozone Transport Commission and the ad hoc Ozone Transport Assessment Group were established, the former in 1991 under the auspices of the federal Clean Air Act Amendments. In the west, where degrading visibility in scenic areas is a growing problem, the Grand Canyon Visibility Transport Commission and its successor, the Western Regional Air Partnership, were established as voluntary organizations representing western states, tribes, and the federal government. The main purpose of these groups is to recommend and implement multi- state mitigation strategies for air pollution that extend beyond any one state border (NRC 2004a).
Meeting the Challenges 171 more proactive approach in addressing both past and potential future impacts of climate change. A wide array of adaptation options is available. The most immediate response is likely to come through changes in transportation operating and maintenance practices. These changes will involve incorporating responses to more extreme weather events into routine operations, improving collaboration with emergency managers, recognizing weather and emergency management as integral functions of transportation agency operations, and widely sharing best practices. To make decisions about rehabilitating or retrofitting transportation infra- structure with long service lives, transportation planners and engineers will need to consider how climate change will affect these facilities 50 years or more into the future. Design changes may also be required to harden long- lived infrastructure in locations particularly vulnerable to climate changes. The development of new standards to address climate change will be a time-consuming process, requiring research and testing and the consensus of practicing engineers. In view of the myriad of potential climate change impacts to be considered, the scientific community and relevant profes- sional organizations should take the lead in initiating a program soon, with federal support for the necessary research and testing. Relocation of some transportation systems, such as coastal roads and rail lines, may ultimately prove necessary. Costly levees or storm barrier systems may be considered to protect valuable real estate in selected densely populated exposed areas. One of the most effective strategies for reducing the risks of climate change is to avoid placing people and infrastructure in vulnerable loca- tions. This is not always possible in highly developed areas, but more stringent land use controls and flood insurance requirements could help curb further development. Federal planning regulations should require that transportation planners take climate change into account in develop- ing long-range plans, as well as collaborate with agencies responsible for land use, so that the consequences of infrastructure investment decisions for land use and vice versa can be more clearly identified. FEMA should reevaluate the risk reduction effectiveness of NFIP. At a minimum, updat- ing of flood zone maps to account for sea level rise (incorporating land subsidence) should be a priority in coastal areas. Better monitoring technologies and new materials could also provide alternatives to costly upgrading of some infrastructure. More widespread use of sensors for monitoring impacts of climate change and new heat- resistant paving materials are examples. More refined data (e.g., better
172 Potential Impacts of Climate Change on U.S. Transportation elevation data for floodplain mapping, more accurate data on surface temperatures) and improved modelingâfrom weather forecasting to modeling of expected storm surge and real-time evacuation scenariosâ are needed as well. Adapting to climate change will also require new partnerships and organizational arrangements that better align with climate impacts than do current modal, jurisdictional, and corporate boundaries around which decision making in the transportation sector is structured. Some models for regional and multistate cooperation exist in regional emergency response initiatives and in regional authorities and compacts for air quality, but state or federal incentives may be necessary to ensure the development of organizations âright-sizedâ to address the problems for transportation infrastructure raised by climate change. At the federal level, an interagency working group could be created, focused solely on adaptation issues for the transportation sector, to help shape existing agency research programs. The U.S. Department of Transportation would be the natural lead for this activity. Embracing these adaptation strategies would require overcoming many of the barriers outlined in Chapter 4. First and foremost, trans- portation leaders would need to agree that climate change is a problem that warrants action. Thinking longer term, adopting more risk-based approaches to investment decisions, and forging new partnerships and organizational arrangements are among the greatest challenges. The next and final chapter provides the committeeâs recommendations for moving forward. REFERENCES Abbreviations ACIA Arctic Climate Impact Assessment ASFPM Association of State Floodplain Managers DHS U.S. Department of Homeland Security FHWA Federal Highway Administration IPCC Intergovernmental Panel on Climate Change NEHRP National Earthquake Hazards Reduction Program NRC National Research Council OFCM Office of the Federal Coordinator for Meteorological Services and Supporting Research
Meeting the Challenges 173 ACIA. 2004. Impacts of a Warming Arctic. Cambridge University Press, United Kingdom. Adams, M. 2006. Strapped Insurers Flee Coastal Areas. USA Today, April 26. Amekudzi, A., and M. Meyer. 2005. NCHRP Report 541: Consideration of Environmental Factors in Transportation Systems Planning. Transportation Research Board of the National Academies, Washington, D.C. ASFPM. 2007. National Flood Policy Challenges. Levees: The Double-Edged Sword. White paper, April 17. www.floods.org/PDF/ASFPM_Levee_Policy_Challenges_ White_Paper_021907.pdf. Bartholomew, K. 2005. Integrating Land Use Issues into Transportation Planning: Scenario Planning, Summary Report. University of Utah. Buckle, I. 2006. Development of Earthquake Engineering Standards for Transportation Structures. Presented to the Committee on Climate Change and U.S. Transportation, Washington, D.C., Jan. 5. Burby, R. J. 2006. Hurricane Katrina and the Paradoxes of Government Disaster Policy. Annals of the American Academy of Political and Social Science, Vol. 604, No. 1, March, pp. 171â191. California Coastal Commission. 2007. Why It Exists and What It Does. www.coastal. ca.gov. Accessed Oct. 2, 2007. Changnon, S. A. 2006. Railroads and Weather: From Fogs to Floods and Heat to Hurricanes, Impacts of Weather and Climate on American Railroading. American Meteorological Society, Boston, Mass. Changnon, S. A., K. Kunkel, and B. Reinke. 1996. The Impacts and Responses to the 1995 Heat Wave: A Call to Action. Bulletin of the American Meteorological Society, Vol. 77, No. 7, July. Deen, T. B. 2006. Preliminary Remarks Outline, Rapporteur. Conference on Climate Change Impacts on U.S. Transportation, Transportation Research Board and Division on Earth and Life Studies, Oct. 12. DHS. 2006. Nationwide Plan Review, Phase 2 Report. June 16. Elliott, D. J. 2005. Federal Flood Insurance After Katrina. Center on Federal Financial Institutions, Washington, D.C. Federal Register. 2007. Statewide Transportation Planning; Metropolitan Transportation Planning; Final Rule. Section 450.322. Vol. 72, No. 30, Feb. 14, pp. 7275â7277. FHWA. 2004. Traffic Congestion and Reliability: Linking Solutions to Problems. Executive Summary. FHWA-HOP-05-004. U.S. Department of Transportation, July. FHWA. 2005a. Coastal Bridges and Design Storm Frequency. Interim Guidance. Office of Bridge Technology, Washington, D.C., Sept. 28. FHWA. 2005b. Scenario Planning: A Holistic Approach to Integrating Land Use and Transportation. Successes in Stewardship, Nov. FHWA. 2006a. Highway Statistics 2005. U.S. Department of Transportation. FHWA. 2006b. Integration of Emergency and Weather Elements into Transportation Management Centers. FHWA-HOP-06-090. U.S. Department of Transportation, Feb. Goldblatt, R. B., and K. Weinisch. 2005. Evacuation Planning, Human Factors, and Traffic Engineering: Developing Systems for Training and Effective Response. TR News, No. 238, MayâJune, pp. 13â17.
174 Potential Impacts of Climate Change on U.S. Transportation HoustonâGalveston Area Council. 2007. The 2035 HoustonâGalveston Regional Trans- portation Plan. Draft Executive Summary, revised May 9. Inside ITS. 2006. Chicago Opens New City Incident Center to Coordinate Communi- cations. Dispatch. Vol. 16, No. 6, March 15. Inside ITS. 2007. Bridge Monitoring Devices Unused. Vol. 17, No. 18, Sept. 15. IPCC. 2007. Summary for Policymakers. In Climate Change 2007: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (M. L. Parry, O. F. Canziani, J. P. Palutikof, P. J. van der Linden, and C. E. Hanson, eds.), Cambridge University Press, Cambridge, United Kingdom and New York. Kinsella, Y., and F. McGuire. 2005. Climate Change Uncertainty and the State Highway Network: A Moving Target. Transit New Zealand. Lockwood, S. A. 2006. Operational Responses to Climate Change Impacts. PB Consult, Dec. 29. Meyer, M. D. 2006. Design Standards for U.S. Transportation Infrastructure: The Implications of Climate Change. Georgia Institute of Technology, Dec. 18. Meyer, M., and E. Miller. 2001. Urban Transportation Planning: A Decision-Oriented Approach. McGraw-Hill, New York. NEHRP. 2007. National Earthquake Hazards Reduction Program: Working to Reduce Earthquake Losses. www.nehrp.gov/about/index.htm. Accessed May 8, 2007. New York City Transit. 2007. Hurricane Evacuation Service Plan and Attachments. June revision. NRC. 2004a. Air Quality Management in the United States. National Academies Press, Washington, D.C. NRC. 2004b. Where the Weather Meets the Road: A Research Agenda for Improving Road Weather Services. National Academies Press, Washington, D.C. NRC. 2007. Base Map Inputs for Floodplain Mapping. National Academies Press, Washington, D.C. OFCM. 2002. Weather Information for Surface Transportation: A National Needs Assessment Report (WIST). FCM-R18-2002. National Oceanic and Atmospheric Administration, Washington, D.C. Soo Hoo, W. K., and M. Sumitani. 2005. Climate Change Will Impact the Seattle Department of Transportation. Office of City Auditor, Aug. 9.
ANNEX 5-1A Potential Climate Changes, Impacts on Land Transportation, and Adaptation Options Impacts on Land Transportation (Highways, Rail, Pipeline) Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Temperature: Limitations on periods Impacts on pavement and Shifting construction Development of new, increases in very of construction concrete construction schedules to cooler heat-resistant hot days and activity due to health practices parts of the day paving materials heat waves and safety concerns; Thermal expansion on Greater use of heat- restrictions typically bridge expansion joints tolerant street and begin at 29.5Â°C and paved surfaces highway landscaping (85Â°F); heat exhaus- Impacts on landscaping in Greater use of continu- tion possible at highway and street ous welded rail lines 40.5Â°C (105Â°F) rights-of-way Vehicle overheating and Concerns regarding pave- tire deterioration ment integrity, e.g., softening, traffic-related rutting, migration of liq- uid asphalt; sustained air temperature over 32Â°C (90Â°F) is a significant threshold Rail-track deformities; air temperature above 43Â°C (110Â°F) can lead to equipment failure (continued)
ANNEX 5-1A (continued) Potential Climate Changes, Impacts on Land Transportation, and Adaptation Options Impacts on Land Transportation (Highways, Rail, Pipeline) Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Temperature: Regional changes in Decreased utility of Reduction in snow and decreases in very snow and ice removal unimproved roads that ice removal cold days costs and environ- rely on frozen ground for Extension of construc- mental impacts from passage tion and main- salt and chemical tenance season use (reduction over- Shortening of season all, but increases in for use of ice roads some regions) Fewer cold-related restrictions for main- tenance workers Temperature: Thawing of permafrost, Shortening of season Use of insulation in the Relocation of sec- increases in causing subsidence of for use of ice roads road prism tions of roads and Arctic tempera- roads, rail beds, bridge Lengthening of poten- Use of different types rail lines to more tures supports (cave-in), and tial construction of passive refrigera- stable ground pipelines season tion schemes, Shorter season for ice Increased use of sonars including thermo- roads to monitor stream- siphons, rock bed flow and bridge galleries, and âcold scour culvertsâ
Temperature: later Changes in seasonal Reduced pavement Relaxation of seasonal onset of seasonal weight restrictions deterioration result- weight restrictions freeze and earlier Changes in seasonal ing from less Shortening of season onset of seasonal fuel requirements exposure to freezing, for use of ice roads thaw Improved mobility and snow, and ice, but safety associated possibility of more with a reduction in freezeâthaw condi- winter weather tions in some Longer construction locations season Sea level rise, More frequent inter- Inundation of roads Elevation of streets, Relocation of sections added to storm ruptions in travel on and rail lines in bridges, and rail of roads and rail surge coastal and low- coastal areas lines lines inland lying roadways and More frequent or severe Addition of drainage Protection of high- rail service due to flooding of under- canals near coastal value coastal real storm surges ground tunnels and roads estate with levees, More severe storm low-lying infrastruc- Elevation and protec- seawalls, and dikes surges, requiring ture tion of bridge, Strengthening and evacuation Erosion of road base tunnel, and transit heightening of and bridge supports entrances existing levees, Bridge scour Additional pumping seawalls, and dikes Reduced clearance capacity for tunnels Restriction of most under bridges vulnerable coastal Loss of coastal wet- areas from further lands and barrier development shoreline Increase in flood Land subsidence insurance rates to help restrict devel- opment (continued)
ANNEX 5-1A (continued) Potential Climate Changes, Impacts on Land Transportation, and Adaptation Options Impacts on Land Transportation (Highways, Rail, Pipeline) Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Return of some coastal areas to nature Precipitation: Increases in weather- Increases in flooding of Expansion of systems Protection of critical Greater use of sen- increase in related delays roadways, rail lines, and for monitoring scour evacuation routes sors for intense precipi- Increases in traffic dis- subterranean tunnels of bridge piers and Upgrading of road monitoring water tation events ruptions Overloading of drainage abutments drainage systems flows Increased flooding of systems, causing back- Increase in monitoring Protection of bridge Restriction of devel- evacuation routes ups and street flooding of land slopes and piers and abutments opment in Disruption of construc- Increases in road scouring, drainage systems with riprap floodplains tion activities road washout, damages Increases in monitoring Increases in culvert Changes in rain, snow- to railbed support struc- of pipelines for expo- capacity fall, and seasonal tures, and landslides sure, shifting, and Increases in pumping flooding that affect and mudslides that scour in shallow capacity for tunnels safety and mainte- damage roadways and waters Addition of slope reten- nance operations tracks Increases in real-time tion structures and Impacts on soil moisture monitoring of flood retaining facilities levels, affecting struc- levels for landslides tural integrity of roads, Integration of emergency Increases in the stan- bridges, and tunnels evacuation proce- dard for drainage dures into operations capacity for new
Adverse impacts of stand- transportation infra- ing water on road bases structure and major Increases in scouring of rehabilitation projects pipeline roadbeds and (e.g., assuming a damages to pipelines 500-year rather than a 100-year storm) Precipitation: Increased susceptibility Increased susceptibility to Vegetation manage- increases in to wildfires, causing wildfires that threaten ment drought condi- road closures due to transportation infra- tions for some fire threat or reduced structure directly regions visibility Increased susceptibility to mudslides in areas deforested by wildfires Precipitation: Benefits for safety and Increased risk of floods changes in reduced interrup- from runoff, landslides, seasonal precipi- tions if frozen slope failures, and tation and river precipitation shifts damage to roads if pre- flow patterns to rainfall, depend- cipitation changes from ing on terrain snow to rain in winter and spring thaws Storms: more fre- More debris on roads Greater probability of infra- Emergency evacuation Changes in bridge Strengthening and quent strong and rail lines, inter- structure failures procedures that design to tie decks heightening of hurricanes rupting travel and Increased threat to stability become more routine more securely to levees (Category 4â5) shipping of bridge decks Improvements in ability substructure and Restriction of further More frequent and Increased damage to signs, to forecast landfall strengthen founda- development in potentially more lighting fixtures and and trajectory of tions vulnerable coastal extensive emergency supports hurricanes locations evacuations (continued)
ANNEX 5-1A (continued) Potential Climate Changes, Impacts on Land Transportation, and Adaptation Options Impacts on Land Transportation (Highways, Rail, Pipeline) Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Decreased expected life- Improvements in moni- Increases in drainage Increase in flood time of highways toring of road capacity for new insurance rates to exposed to storm surge conditions and transportation infra- help restrict issuance of real-time structure or major development messages to rehabilitation proj- Return of some motorists ects (e.g., assuming coastal areas to Improvements in mod- more frequent return nature eling of emergency periods) evacuation Removal of traffic bot- tlenecks on critical evacuation routes and building of more system redundancy Adoption of modular construction tech- niques where infra- structure is in danger of failure Development of modular traffic features and road sign systems for easier replacement
ANNEX 5-1B Potential Climate Changes, Impacts on Marine Transportation, and Adaptation Options Impacts on Marine Transportation Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Temperature: Impacts on shipping increases in very due to warmer water hot days and in rivers and lakes heat waves Temperature: Less ice accumulation Improvement in operat- decreases in very on vessels, decks, ing conditions from cold days riggings, and docks; less ice accumula- less ice fog; fewer tion, fog, and jams ice jams in ports Temperature: Longer ocean transport Longer ice-free ship- increases in season and more ping season and Arctic tempera- ice-free ports in increased access to tures northern regions more ice-free ports Possible availability of and resources in a Northern Sea Route remote areas or a Northwest Longer season for Passage barge transport (continued)
ANNEX 5-1B (continued) Potential Climate Changes, Impacts on Marine Transportation, and Adaptation Options Impacts on Marine Transportation Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Temperature: later Extended shipping Increases in summer Design of shallower- More dredging, but onset of seasonal season for inland load restrictions bottom vessels for environmental and freeze and earlier waterways (especially seaway travel institutional issues onset of seasonal the St. Lawrence Shifts to other trans- thaw Seaway and the portation modes Great Lakes) due to reduced ice coverage Sea level rise, More severe storm Changes in harbor and port More frequent bridge Raising of dock and More dredging of added to storm surges, requiring facilities to accommo- openings to handle wharf levels and some channels surge evacuation date higher tides and shipping retrofitting of other Raising or construc- storm surges facilities to provide tion of new jetties Reduced clearance under adequate clearance and seawalls to bridges Protection of terminal protect harbors Impacts on navigability of and warehouse channels: some will be entrances more accessible (and Elevation of bridges farther inland) because and other structures of deeper waters, while others will be restricted because of changes in sedimentation
Precipitation: Increases in weather- Impacts on harbor infra- Strengthening of harbor More dredging on increase in related delays structure from wave infrastructure to pro- some shipping intense precipita- damage and storm tect it from storm channels tion events surges surge and wave Changes in underwater damage surface and silt and Protection of terminal debris buildup can affect and warehouse channel depth entrances from flooding Precipitation: Impacts on river trans- Restrictions on ship- More dredging on increases in portation routes and ping due to channel some shipping drought condi- seasons depth along inland channels and tions for some waterways and on harbors regions other river travel Release of water from upstream sources Shifts to other trans- portation modes Precipitation: Periodic channel clos- Changes in silt deposition Restrictions on ship- More dredging on changes in ings or restrictions if leading to reduced depth ping due to channel some shipping seasonal precipi- flooding increases of some inland water- depth along inland channels tation and river Benefits for safety and ways and impacts on waterways and on flow patterns reduced interrup- long-term viability of other river travel tions if frozen some inland navigation precipitation shifts routes to rainfall (continued)
ANNEX 5-1B (continued) Potential Climate Changes, Impacts on Marine Transportation, and Adaptation Options Impacts on Marine Transportation Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Storms: more fre- Implications for emer- Greater challenge to robust- Emergency evacuation Hardening of docks, quent strong gency evacuation ness of infrastructure procedures that wharves, and termi- hurricanes planning, facility Damage to harbor infra- become more routine nals to withstand (Category 4â5) maintenance, and structure from waves storm surge and safety management and storm surges wave action Damage to cranes and other dock and terminal facilities
ANNEX 5-1C Potential Climate Changes, Impacts on Air Transportation, and Adaptation Options Impacts on Aviation Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Temperature: Delays due to excessive Heat-related weathering Increase in payload Development of new increases in very heat and buckling of pave- restrictions on air- heat-resistant run- hot days and Impact on lift-off load ments and concrete craft at high-altitude way paving materials heat waves limits at high-alti- facilities or hot-weather air- Extension of runway tude or hot-weather Heat-related weathering of ports lengths at high- airports with in- vehicle stock Increase in flight can- altitude or hot- sufficient runway cellations weather airports, if lengths, resulting in feasible flight cancellations or limits on payload (i.e., weight restric- tions), or both More energy consump- tion on the ground Temperature: Changes in snow and Reduction in snow and decreases in very ice removal costs ice removal cold days and environmental Reduction in airplane impacts from salt deicing and chemical use Reduction in need for deicing (continued)
ANNEX 5-1C (continued) Potential Climate Changes, Impacts on Air Transportation, and Adaptation Options Impacts on Aviation Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Fewer limitations on ground crew work at airports, typically restricted at wind chills below â29Â°C (â20Â°F) Temperature: Thawing of permafrost, Development of new Relocation of some increases in undermining runway runway paving mate- landing strips Arctic tempera- foundations rials tures Major repair of some runways Temperature: later onset of seasonal freeze and earlier onset of seasonal thaw Sea level rise, Potential for closure or Inundation of airport run- Elevation of some run- Construction or rais- added to storm restrictions for sev- ways located in coastal ways ing of protective surge eral of the top 50 areas dikes and levees airports that lie in
coastal zones, Relocation of some affecting service to runways, if the highest-density feasible populations in the United States Precipitation: Increases in delays due Impacts on structural More disruption and Increases in drainage increase in to convective integrity of airport facili- delays in air service capacity and intense precipita- weather ties More airport closures improvement of tion events Storm water runoff that Destruction or disabling of drainage systems exceeds the capacity navigation aid instru- supporting runways of collection sys- ments and other paved sur- tems, causing Runway and other infra- faces flooding, delays, and structure damage due to airport closings flooding Implications for emer- Inadequate or damaged gency evacuation pavement drainage planning, facility systems maintenance, and safety management Precipitation: Decreased visibility at increases in airports located in drought condi- drought-susceptible tions for some areas with potential regions for increased wild- fires (continued)
ANNEX 5-1C (continued) Potential Climate Changes, Impacts on Air Transportation, and Adaptation Options Impacts on Aviation Adaptation Options Changes in Potential Climate Operations and Infrastructure Design Change Interruptions Infrastructure Changes in Operations and Materials Other Precipitation: Benefits for safety and Inadequate or damaged Increases in drainage changes in reduced interrup- pavement drainage capacity and seasonal precipi- tions if frozen systems improvement of tation and river precipitation shifts drainage systems flow patterns to rainfall supporting runways and other paved sur- faces Storms: more fre- More frequent interrup- Damage to landside facili- Hardening of terminals quent strong tions in air service ties (e.g., terminals, and other facilities hurricanes navigation aids, (Category 4â5) fencing around perimeters, signs)