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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
×
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
×
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
×
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
×
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
×
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
×
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Suggested Citation:"Chapter 5 - Common Benefits." National Academies of Sciences, Engineering, and Medicine. 2020. Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook. Washington, DC: The National Academies Press. doi: 10.17226/25744.
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41 Losses Avoided For hazard mitigation and resilience projects, benefits are typically avoided damages and losses, as shown in Equation 7. Equation 7. Determining project benefits. BENEFITS Pre PROJECT EVENT DAMAGES AND LOSSES Post PROJECT EVENT DAMAGES AND LOSSES Σ Σ ( ) ( ) = − − − Avoided damages and losses are physical damage and service losses that would occur as the result of a hazard or incident if the project were not undertaken. For example, if a 100-year flood event will cause $1 million in damages, a resilience project that will protect against the 100-year flood event with no residual damages has avoided losses valued at $1 million, which is consid- ered a project benefit. Project benefits occur over a future period of time, while most project costs are incurred up front and in the present. For this reason, benefits are more difficult to estimate than costs. Furthermore, many benefits that come with avoidance are difficult to quantify. Zillow’s analysis provides one indication of costs of the current (business-as-usual) path and thus some indication of the savings that may be achieved by avoiding it. Yet, Zillow analyses apply only to residen- tial property, not to the residential streets, arterials, local and state highways, and interstates connecting them, or to the other public resources such as schools, parks, libraries, government buildings, and more (not to mention the private sector businesses providing much of an area’s employment). The National Climate Assessment (USGCRP, 2014) also points out that we are currently pursuing a path whereby the consequences of climate change could be beyond adaptation: 18°F Arctic warming, sea levels rising 1 foot per decade, and widespread drying—or Dust-Bowlification as Joe Romm (2017) called it in Scientific American and the scientific journal Nature—along with 8°F to 10°F warming over the interior of this country (Figure 14) (NASA, 2015). These are averages; the temperature extremes that occur annually are higher already and would be much higher in the future, continuing on our current path. In that case, global sea levels may rise 8 feet, inundating every major coastal city in the United States and around the world by century’s end. (The Intergovernmental Panel on Climate Change estimated 2 meters of sea level rise [SLR] could occur this century on the current path. NASA scientists and others have said that over 3 meters of SLR by 2100 is possible.) Seas would keep rising by more than 1 foot a decade thereafter, making adaptation all but impossible. The unaffordability and impossibility of adapting to the degree of climate, food system, security, and economic change in store makes a rapid shift to new technologies our best, lowest-risk, C H A P T E R 5 Common Benefits

42 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook most cost-effective bet. However, because these technologies are new and not completely proved, quantifying the benefits from their implementation could be challenging. Further, some technologies still in development could become available at some point in the future; these technologies cannot be accounted for in CBAs performed today. CBAs can be completed based on the best available information at the time then re-calculated in the future based on newly available information as appropriate. Most climate adaptations are incorporated with the objective of reducing damage from future natural hazard events; however, some projects might also seek to improve existing conditions under normal operations, and as such the project has direct benefits. Both losses avoided and direct benefits are considered to be benefits in a CBA; however, care needs to be taken not to double-count benefits. Double-counting occurs most frequently with transfer payments and counting the same economic impact twice. An example of double-counting a transfer payment is when a toll is reduced and the analysis also includes lower vehicle-operating costs, even though the cost of collecting the toll remains unchanged (bca.transportationeconomics.org). The toll is a transfer payment between the transportation agency and the user and therefore is not included in a CBA. An example of counting the same economic impact twice is the construction of a noise barrier. If the cost of constructing the barrier is included in the project costs, the disbenefit (or negative benefit) of noise from the project without the wall would not be included in the CBA. Damage Reduction Damages from a natural hazard event (such as a flood) can include physical damages to facili- ties as well as related costs. Avoiding or reducing these damages by implementing adaptation measures to accommodate future expected conditions is considered a benefit in a CBA. Benefits that can be realized by avoiding damages are grouped into the following five categories. (One category, transportation service losses, can be a significant source of damages/losses for trans- portation agencies, and is therefore described in greater detail.) Figure 14. Gradual warming of the atmosphere over the interior of the United States will decrease soil moisture (NASA, 2015).

Common Benefits 43 • Physical damages include the cost of permanent repair or replacement of fixed facilities (roads, bridges, structures) and associated equipment (movable signs, agency vehicles, equip- ment, and contents of structures). Physical damages can occur to buildings that support transportation operations; building contents; infrastructure, including utility and transpor- tation elements; vehicles; equipment; and site features such as landscaping, environmental contamination, or erosion. Physical damages are often the largest component of the total damages resulting from a natural hazard event. Physical damages to transportation assets could include damages to roads, bridges, and tunnels; support structures such as culverts, embankments, guardrails, and signs; and support facilities such as administrative offices, toll plazas, and weigh stations. • Response and recovery costs include initial emergency protective measures and other temporary facilities established in response to natural hazard events to facilitate recovery of basic transportation service. Some examples of response and recovery costs include sand- bagging to protect entrances and openings to facilities, deploying flood barriers and flood gates, and pumping floodwater out of facilities. Transportation agencies might also tempo- rarily close vulnerable parts of the system such as roads susceptible to flooding or bridges affected by high winds, and put up temporary signs to guide network users through detours and evacuation routes. Such costs may include DOT or agency force account labor, invoiced contractor labor, or volunteer labor estimated based on local average hourly wages. The costs may also include the materials used, such as sandbags and sand. • Other damage costs are miscellaneous costs associated with natural hazard events, including lost revenue, debris removal, and cleanup costs needed to restore transportation service to pre-event conditions. Loss of revenue could occur for toll roads, tunnels, and bridges; bus routes; ferry service; and train or subway fares if these systems are rendered temporarily inoperable as a result of the hazard event. Records will likely indicate how long the system component was out of service, the fare structure, and average daily traffic (ADT) for the time the system was inoperable. • Losses to the local economy can occur as a result of a loss of the transportation systems serving the impacted communities. Losses occur when consumer spending decreases as a result of the hazard event affecting accessibility to primary industries served by the transportation network. Examples include decreased levels of tourism and decreased attendance at sporting events, theater performances, arts events, and restaurants. When considering if losses to the local economy will be included in a CBA for grant applications, applicants need to review the requirements of the particular grant program; not all grant programs allow economic losses outside of the transportation network itself to be included in the analysis. However, economic losses can be significant if a particular segment of the transportation network is rendered inoperable for a period of time, which can be considered when analyzing project alternatives. • Transportation service losses are the economic losses and additional mileage costs associated with the loss or delay of damaged transportation systems as well as with the secondary impacts on alternate transportation services, such as increased time and traffic caused by detours around a disaster-damaged road or bridge. These losses may be particularly considered for freight, as the impacts of events such as extreme heat can result in vehicle weight restrictions for certain roadways. These losses are discussed further in the following section. Transportation Service Losses Transportation service losses have a variety of impacts that can be avoided or reduced by the implementation of climate-adapted projects. For example, the loss of a key road or bridge could require the use of additional temporary bus or mass transit services that increase traffic and

44 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook travel times while repairs are made. However, a climate adaptation could lessen or eliminate damage to the road or bridge, which would in turn reduce the use of additional bus or mass transit services, since the required repairs could presumably be made more quickly or might not be required at all. Common service losses that can be included for consideration of losses avoided in a CBA include • Cost of road or bridge service. The unit cost of road or bridge service can be based on a standard value reflecting the value of people’s time. U.S. DOT published values of national averages in its annual BUILD guidance and continues to do so in relation to its discretion- ary grant programs (US DOT 2020). Regional values can be determined using Bureau of Labor Statistics values for average hourly wages; the FEMA Benefit-Cost Analysis Toolkit (Version 5.3.0) and the FTA Hazard Mitigation Cost-Effectiveness Tool (Version 2.2) use standard national average values that can be adjusted to reflect regional cost differences where appropriate. Standard values are based on national average values reflecting loss of regional economic impacts; therefore, no adjustments to the number of trips are required to account for residential versus commercial or emergency vehicles. • Delay or extra travel time. The delay or extra travel time associated with road or bridge damage is usually recorded as hours of delay per trip and can be documented by the respon- sible agency or by using maps with detour travel times and associated mileages from online sources. When no alternative route or detour is available, the extra travel time can be set to a maximum of 12 hours per one-way trip and supported by a map showing no detour is available. • Number of affected vehicles. The number of affected vehicles for roads is generally based on ADT counts prepared by the state or local DOT. The number of affected vehicles for bridges can be based on ADT counts prepared by the state or local DOT or by ADT data collected by the transportation agency that owns or operates the bridge. For grant appli- cations, whenever possible, the ADT counts will be provided by the responsible agency or included in a signed letter from a local official. For smaller subdivision roads or crossings where traffic counts are unavailable, users can estimate one-way trips using the TRB Highway Capacity Manual (2016) or other recognized sources. • Loss of function durations. The duration of service losses or reductions is based on the number of hours, days, or weeks that the transportation asset is out of service. The service losses associated with each historic event can be obtained from state or local DOT records, other agency records, disaster damage worksheets (i.e., FHWA Damage Assessment Forms or FEMA Project Worksheets), or news articles citing credible sources where the date of the article can be linked to the date of the event. • Additional mileage. The additional mileage associated with traveling around a flood- damaged road or bridge can be documented by the responsible agency or by using copies of maps with detour travel times and associated mileages from online sources. This additional mileage can then be multiplied by the number of affected vehicles and the standard mileage rate for privately owned vehicles, which can be found on the General Services Administration website (https://www.gsa.gov/travel/plan-book/transportation-airfare-rates-pov-rates-etc/ privately-owned-vehicle-pov-mileage-reimbursement-rates). Once the additional mileage data are collected, the additional loss of service for each event can be determined based on the formula in Equation 8. Equation 8. Calculating loss of transportation service to be included in a CBA. $ ( ) ( ) Additional Loss of Service Vehicle Mile Number of Affected Vehicles Loss of Function Duration Additional Mileage Vehicle( ) ( )= × × ×

Common Benefits 45 Sources of Data Sources of data for determining these benefits can include historic information as well as predicted costs based on planning and engineering studies. Some common data sources include • Historic records. Agencies can use data from previous incidents to develop estimates of physical damages, response and recovery costs, and other damages. – Disaster damage worksheets. Disaster damage worksheets such as FHWA Damage Assess- ment Forms or FEMA Project Worksheets are useful for documenting historic damages to transportation facilities from presidentially declared disaster events. Such damage worksheets may include permanent repair and restoration of physical damages as well as response and recovery costs. – Repair records. Repair records from a state or local DOT or Department of Public Works may be useful for documenting historic damages to various transportation facilities from flood events. Such repair records may include records of expenditures in financial data- bases, receipts for repairs or equipment rental, or force account labor records, and may be supported by other documentation such as news articles or community and agency board meeting minutes. Complete copies of records need to be included in grant applications, with costs organized in a spreadsheet. – Flood insurance claims. Insurance claim data may be useful for documenting physical damages to insured properties from various flood events. Flood insurance claim data on all properties insured under the National Flood Insurance Program are available through BureauNet (https://nfipservices.floodsmart.gov/home/reports). Transportation agencies can register to obtain information on the various properties insured under the National Flood Insurance Program within their community. Additional benefits may be estimated from flood claims data when other event information is available. For example, if the flood claim lists only building damages, but the building type and size and the depth of flooding in the building are known, then FEMA depth-damage functions can be used to extrapolate contents damages and even displacement costs for that event. – News articles citing credible sources. News articles can include nationally or locally published newspapers or newsletters that are printed or posted online. Articles are most useful if they indicate the specific dates and impacts to facilities to be addressed by the proposed project. • Engineering reports. These reports can indicate estimated damages to various types of transportation facilities based on similar historic events or detailed engineering analysis. • Transportation agency studies. Agency studies provide another good source of estimated damages to transportation facilities. • Software estimates. For transportation structures such as administration buildings and storage facilities, expected flood damages can be estimated using software such as the BCA software or HAZUS-MH, both offered by FEMA: – Flood damages to buildings can be estimated using depth-damage functions based on structure information (building type, number of stories, foundation type, size and building replacement value) as a function of flood depth above the first-floor elevation. It is impor- tant to establish the correct reference point for the first-floor elevation before applying the depth-damage functions. – Depth-damage functions can be documented from the FEMA BCA software or the HAZUS-MH output, or transcribed into a separate document or spreadsheet. – Structure information can be documented from various sources, including tax records, struc- ture plans with dimensions, site photographs, engineering reports, and building cost data. Other software such as the U.S. Army Corps of Engineers’ HEC-FIA and HEC-WAT may also be used to estimate damages to buildings from flooding.

46 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook Once these historic flood damages are determined, the total damage cost for each event can be determined based on the formula in Equation 9: Equation 9. Calculating total damages. ( )Total Damage Physical Damage Response and Recovery Other Damage( ) ( )= + + System Costs DOTs have less experience including systemwide costs and other more indirect costs, but estimates of these costs are sometimes available from insurance partners and past disasters. For example, business closure and continuity costs, business loss costs, job loss costs, and cumulative individual and community impacts may all stem from lack of transportation system access or availability. These costs are substantial. They are tied to the DOT’s core mission and may affect more than one mode of transportation. In some cases, the magnitude of system costs can tip the balance toward the importance or necessity of avoiding disruption, and this is when adap- tation planning projects present the clear economic benefits of avoiding climate change in the first place. System costs can even be deemed a necessity when considering unpayable costs. For this reason, transportation system costs typically involve different decisions than the ones used to determine the size of infrastructure. Rational and comprehensive planning will extend to these real-life, systemwide impacts, and consider how they can or should be avoided and how the agency or jurisdiction can contribute. Additional flood-related costs beyond increased heavy storms (see Figure 15) or sea level rise come from increasing “sunny day” or “nuisance” flooding from tides, which are also higher with rising seas (USGCRP, 2014). What are the tipping points for cities or other areas? NASA (2015) and Sweet et al. (2017) looked at property and city areas subject to repeat inundation 26 times per year or more, making some parts of the city inaccessible (e.g., areas that could be abandoned earlier). What are the thresholds for habitation? When cars and trucks can no longer be insured? Currently, 60,000 miles (96,561 kilometers) of roadways are exposed to coastal storms (Douglass et al., 2014). In the future, rising seas will cause more severe events and more frequent disruptions and damage, and storm-surge impacts will extend further inland. For example, the Figure 15. An increasing number of heavy precipitation events will increase flood-related costs for transportation agencies (USGCRP, 2014).

Common Benefits 47 storm-surge extent from Hurricane Sandy in 2012 matches or is exceeded by the chronic (twice a month) inundation by 2100 (Dahl, 2017). Over the past 20 years, the frequency of nuisance floods has nearly doubled and is projected to continue to increase at all locations; the total induced vehicle hours of delay caused by nuisance flooding currently exceeds 100 million hours annually and could exceed 1 billion vehicle hours by 2060 (Jacobs et al., 2018). In fact, Schrank et al. (2015) estimated that in 2014, total travel delay for the United States was 6.9 billion hours. Vehicle hours of delay from nuisance flooding on the East Coast alone will exceed that level by 2100 for the intermediate scenario, and by 2060 for the extreme scenario in Jacobs et al. (2018). On November 5, 2017, many cities marked where the highest king/astronomical tide of the year reached; that is where they can expect the water to be most days by 2050, meaning, for example inundating low-lying areas throughout Charleston, South Carolina, and Hampton Roads, Virginia, with water peaking at 2 feet above mean sea level. Scientists have now docu- mented a record number of “nuisance flooding” events during high tides. During high tides in 2014, nearly half of residents in Hampton Roads, Virginia, could not get out of their neighbor- hoods at least once because of tidal flooding (Virginia Institute of Marine Science, 2017). Environmental Benefits Most often, environmental benefits incorporated into a transportation CBA are “losses avoided” from a reduction in emissions to the atmosphere (i.e., improved air quality). In addi- tion to the financial benefits that can be realized from avoided losses, some transportation climate adaptation projects also provide environmental/ecosystem services that add, expand, or improve beneficial goods and services provided by nature for people and the environment. Such beneficial environmental/ecosystem services include providing food, air quality, water quality, wildlife habitat, regulation of natural processes (i.e., flood, drought, and wildfire control), climate, and open space for recreation or other beneficial uses. For example, a bioswale or rain garden can delay and decrease the flow of stormwater runoff, reducing nuisance flooding across a key road while improving water quality, air quality, and aesthetics (Figure 16). Trees planted to help control stormwater runoff could also help improve air quality, which might be considered a co-benefit. Co-benefits are additional benefits that result from an implemented action or policy above and beyond the primary intended benefit. Some other common co-benefits of climate adaptation measures include improved health and wellness, improved water quality, and reduced erosion. Figure 16. Green infrastructure techniques such as bioswales can reduce the velocity and volume of stormwater runoff while also capturing and biologically degrading pollutants carried by stormwater runoff (figure courtesy of Dewberry).

48 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook Greenhouse Gas Emissions As discussed in Chapter 3, GHGs are one of the major contributors to climate change. These gases are composed primarily of CO2, which accounts for over 80 percent of all GHGs in the United States, but also include methane (CH4), nitrous oxide (N2O), and fluorinated gases (from air conditioning, refrigeration, and industrial processes). In fact, the CO2 concentration has risen about 40 percent to 403 parts per million (ppm) over the past 150 years, with an average growth of 2 ppm per year in the last 10 years (and 3 ppm over the last year) (World Meteoro- logical Organization, 2017). Unfortunately, the residence time of GHGs in the atmosphere is expressed in terms of centuries rather than years or even decades, as shown in Figure 17. According to the EPA’s U.S. Greenhouse Gas Inventory Report: 1990–2014 (https://www.epa.gov/ ghgemissions/us-greenhouse-gas-inventory-report-1990-2014) (U.S. EPA, 2016c), the trans- portation sector accounts for approximately 26 percent of GHGs in the United States as the result of burning fossil fuels such as gasoline and diesel in vehicles. The EPA’s Motor Vehicle Emission Simulator (MOVES) program (https://www.epa.gov/moves) can be used to esti- mate emissions for mobile sources at the national, county, and project levels. California also has models that can estimate emissions, such as the EMFAC model and the California Air Resources Board’s Greenhouse Gas Inventory. Figure 17. Greenhouse gases remain in the atmosphere for centuries after they are emitted (Solomon et al., 2009).

Common Benefits 49 Many attempts have been made to monetize the value of GHGs so that their impacts to the economy can be calculated and incorporated into economic models. The social cost of carbon is the monetized value of damages caused by a 1 ton increase in GHG emissions in a given year (Brookings Institution, 2017). Current monetized estimates used in the United States come from the Interagency Working Group (IWG) on the social cost of carbon (SC-CO2). They produce four estimates: • Cost per metric ton avoided for a 5 percent discount rate and the average of SC-CO2 model estimates • Cost per metric ton avoided for a 3 percent discount rate and the average of SC-CO2 model estimates • Cost per metric ton avoided for a 2.5 percent discount rate and the average of SC-CO2 model estimates • Cost per metric ton avoided for a 3 percent discount rate and the 95th percentile of the frequency distribution of SC-CO2 model estimates. The IWG states that ranges of 7 to 23 percent should be used to adjust the global values to domestic values. The values per metric ton of CO2 current as of this writing are available on the EPA’s Social Cost of Carbon technical support document (2010b). From a cost-benefit perspective, a key element in the analysis is the consideration of trade-offs between a business-as-usual approach and an adaptive approach to addressing GHG-reduction concerns. Many DOTs are charged with GHG-mitigation efforts, such that sometimes reduc- tions in GHGs are incorporated into capital-improvement projects as a benefit, often qualita- tively, as the losses or benefits produced by GHGs affecting the atmosphere cannot be reliably quantified in dollars for a CBA estimate. Nonetheless, when transportation agencies are endeav- oring to make a choice between two options with similar CBAs, they may find it useful to also consider whether one option better meets the agency’s GHG-mitigation goals and qualitatively “weight” that option. For example, a DOT is considering two adaptation projects, one that has little impact on GHGs and the other that reduces GHGs in accordance with the agency’s long- term goals. The project having little impact on GHGs has a BCR of 1.05, while the project that reduces GHGs has a BCR of 1.01. Both projects are considered cost-effective, with the project that does not reduce GHGs being slightly more cost-effective than the project that does reduce GHGs. Because the DOT has GHG-reduction goals and the project is cost-effective, the agency might qualitatively state the project that reduces GHGs also helps to meet other program goals, and hence is considered the better option. In essence, with close CBA estimates, the potential for GHG reduction (or comparatively lower emissions) could be used as a tiebreaker for agencies that also have GHG-mitigation missions. Other Emissions/Air Pollution In addition to GHGs, transportation system assets can release other gases that are harmful to the atmosphere and human health. Chief among these are nitrogen oxides (NOx), which form when fuel is burned at high temperatures. NOx play a major role in mixing with other volatile organic compounds in the air to form smog on hot summer days (U.S. EPA Region 1, 2019). The IWG also developed a monetized estimate for the value of NOx reductions in the United States. The estimate range varies by a factor of 10 (Interagency Working Group, 2016). FHWA’s Benefit-Cost Analysis Guidance for Discretionary Grant Programs provides recommended values to use in CBAs for NOx and other emissions (available from https://www.transportation.gov/ office-policy/transportation-policy/benefit-cost-analysis-guidance). Air pollution is now the world’s largest single environmental health risk, and combustion motor vehicles are a contributor. The science is significantly more established than that on climate change, according to Dr. George Thurston, co-author of the World Health Organization’s Global

50 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook Burden of Disease air pollution report (GBD 2015 Chronic Respiratory Disease Collaborators, 2017), who says, “The relationship between ambient air pollution exposure and human mortality is even more definitively quantified, with a broad scientific consensus, than the relationship between human activity and climate change, likely because death is a more definitively defined endpoint than climate change” (Howard, 2017). Many of our key transportation challenges are interrelated. Air pollution has driven many of the fastest movers (London, Paris, China) to accelerate the phaseout of fossil fueled vehicles. Further, health and well-being is one of Americans’ highest areas of concern and interest across the political spectrum, and health and well-being turns out to be more affected by traffic and air pollution than previously realized. Doctors and researchers are quantifying much more extensive mental and physical implications than the “old set” typically cited (i.e., asthma, emer- gency room visits, lung cancer, stroke, and early death). In Los Angeles, for example, more than 5,000 people die prematurely from air pollution every year, more than from traffic accidents and crime combined (SCAQMD and CARB, 2011). The “right to public health” and life free of these pollutants are emerging themes among the public, doctors, and health advocates that will increasingly affect transportation agencies. Already agency executives in multiple countries have made announcements to this effect. A recent report by the American Lung Association estimates the costs of climate and air pollution from passenger vehicles in California to be $15 billion annually (Holmes-Gen and Barrett, 2016). Noise As was briefly discussed in Chapter 4, noise can be annoying and even harmful to humans by impairing hearing, increasing stress, and disturbing sleep. Projects that significantly reduce ambient noise from transportation operations are considered beneficial and can be included in a CBA. Conversely, significant increases in ambient noise from transportation operations are considered a disbenefit in a CBA. It can be difficult to assign a monetary value to noise impacts. As previously discussed, noise abatement measures are typically included as a project cost. In some cases, though, significant noise differences can affect surrounding property values such that the difference can be included in the CBA as a benefit (or a negative benefit, depending on the circumstance). Incorporating Environmental Benefits into Cost-Benefit Analysis Based on the data from the IWG, U.S. DOT publishes values of emissions with their discre- tionary grant application materials. Values for volatile organic compounds, NOx, particulate matter, and sulfur dioxides (SOx) are fixed. GHG values vary with time and discount rate; TIGER provided tables for the 3 percent discount rate, but FY 2018 guidance does not include a recom- mended value because the guidance documents on which the TIGER tables were based have been rescinded. The FY 2018 guidance indicates that any such discounts should be at the same rates as costs and other benefits quantified in the CBA and should be based on the domestic damages of such emissions, rather than on global values. Social Benefits Not all adaptation measures will be developed and designed solely for the purpose of avoid- ing future damages and losses. Some might also be designed to provide a specific benefit. While these measures might not be incorporated solely for climate adaptation, their benefits can be included in a CBA.

Common Benefits 51 Increase in Active Transportation Implementation of active transportation modes such as bicycle lanes provides social benefits in terms of health and livability, in addition to environmental benefits associated with decreased GHGs. A bicycle lane designed and constructed to decrease traffic congestion can lead to fewer vehicles on the road, which results in lower vehicle-operating costs for people who choose to use the bicycle lane rather than drive, also resulting in permanent decreases in GHGs and other emissions. Individuals who use the bicycle lanes might also experience health benefits associ- ated with exercise. See Table 16-123, “Summary of Findings on Direct Relationships Between the Non-Motorized Travel Environment and Measures of Adult Exercise and Health” in TCRP Report 95: Traveler Response to Transportation System Changes Chapter 16—Pedestrian and Bicycle Facilities (http://www.trb.org/Publications/Blurbs/167122.aspx). Environmental Justice Low-income and minority neighborhoods and communities may be more significantly affected by climate change and extreme weather events than the general population because they have fewer resources available to cope with these impacts. For example, some low-income households do not have private automobiles and must rely on public transportation. During natural hazard emergencies such as hurricanes and floods, their ability to evacuate depends on the availability of public transportation. During heat waves, public transportation users may need to wait outside in the extreme temperatures, which could adversely affect their health as a result of heat-related illnesses or poor air quality. Low-income neighborhoods are often located in areas with lower property values associated with greater risk, such as in floodplains (Lee and Jung, 2014). Climate adaptation strategies for transportation systems can contribute positively or negatively to environmental justice. Care needs to be taken to minimize adverse impacts, such as designing transportation improvements to direct surface water runoff away from communities in low-lying areas. Including these susceptible populations in the planning process can result in positive impacts such as the development of more walkable communities, which could decrease adverse health impacts associated with exposure to poor air quality and actually improve health impacts from exercise. Expanding low-cost transportation options could also provide greater mobility for low- income households. Green infrastructure projects such as bioswales or tree planting can not only decrease flooding but also improve water quality, improve aesthetics, and provide shade on hot days. FHWA and EPA have several publications available to help transportation agencies minimize adverse impacts from climate change on communities while providing transportation benefits. Stress and Anxiety Disasters that cause loss of transportation function can increase stress and anxiety on system users as they are forced to find alternative means of getting to and from various locations such as work. This added stress can result in lost productivity. In some cases, the anxiety induced by a disaster can require people to seek mental health treatment. Several agencies, such as FEMA, allow the mental stress prevented by an adaptation project to be included in a CBA. FEMA’s Final Sustainability Benefits Methodology Report (2012) provides additional information about estimating the values of avoided mental stress. Much is not covered in climate change cost and impact estimates. Climatewise, a volun- tary group made up of 28 of the some of the world’s biggest insurance companies, has warned extreme weather disasters have put this year on track to be one of the most expensive on record, urging the insurance industry to redouble efforts to tackle the huge shortfall in global coverage. Climatewise has found that extreme weather disasters over the past decade have contributed

52 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook to a global climate risk protection gap of $1.7 trillion, the majority of which has been borne by governments and civil society (Holder, 2017). In a recent update, Climatewise has detailed how a growing “climate risk protection gap” has been exposed by 2017 events such as Hurricane Har- vey in Texas, which alone cost the United States $180 billion in losses. This does not begin to assess mental stress resulting from losses of (or difficult interruptions in) transportation, work and employment, and housing and other familial disruptions. Aesthetics and Other Difficult-to-Quantify Benefits Some transportation improvements, particularly vegetative improvements intended to help lessen the impacts of heavy precipitation and flood, are also aesthetically pleasing to trans- portation system users and the local community. The aesthetic value, while real, is difficult to quantify, as each individual places a different value on it. Often, aesthetic benefits and other difficult-to-quantify benefits are included in a CBA as qualitative benefits and such improve- ments to public space are increasingly acknowledged and valued. A written description of the measure and the benefit it provides is included with the quantitative CBA so that all benefits offered by a particular approach are captured and compared with the evaluation criteria during the project selection process. Safety Safety is of paramount importance to transportation systems; as part of the FAST Act of 2015, over $2 billion per year is budgeted to the Highway Safety Improvement Program to improve highway safety on public roads to achieve a significant reduction in traffic fatalities and serious injuries. Projects that will reduce losses by improving safety need to include these reduced losses in the CBA. Some significant safety considerations include • Loss of life. Flooded roadways pose a safety hazard to vehicles as wheels lose contact with the road, resulting in vehicles crashing or being washed away. Adaptation projects that reduce risks from flooding and other natural hazards can help reduce loss of life. The value of statistical life (VSL) can be determined using the most current discretionary grant guidance, which is updated annually and available from the U.S. DOT Office of Transportation Policy website (https://www.transportation.gov/policy/transportation-policy). While loss of life is currently calculated only in connection to impacts to vehicles and accidents, there are loss of life impli- cations for other transportation decisions (emissions and resulting health and safety issues); fossil fuel emissions have short-term, well-established loss-of-life impacts caused by inflamma- tion and disease, as well as longer range impacts via climate change. • Injuries. Improving passenger and pedestrian safety is a primary objective of many trans- portation resilience projects; other projects realize safety as a secondary benefit. For example, elevating a roadway or bridge above the predicted 100-year flood level for 2090 will not only help protect the bridge from future flood damage but it will also protect the safety of bridge users. Ultimately this safety improvement results in fewer injuries to asset and system users. The reduction in expected injuries owed to transportation resilience projects needs to be included as a benefit (loss avoided) in a CBA. In addition to the VSL, U.S. DOT pub- lishes values for five different levels of severity of injuries and includes these values with its discretionary grant BCA Resource Guide (Table 9). • Property damage only from crashes. In many cases car crashes may not injure occupants or pedestrians but do damage the vehicles involved. Transportation resilience projects could improve safety such that the number of crashes is reduced. The reduction in property damage from crashes resulting from safety improvements can be included in a CBA as a benefit (loss avoided). U.S. DOT includes a value for damage to property only from crashes in its BCA Resource Guide.

Common Benefits 53 Maximum Abbreviated Injury Scale (MAIS) Level Severity Fraction of VSL MAIS 1 Minor 0.003 MAIS 2 Moderate 0.047 MAIS 3 Serious 0.105 MAIS 4 Severe 0.266 MAIS 5 Critical 0.593 Fatal Not Survivable 1.000 Table 9. U.S. DOT–recommended values of injuries (2018). • Delays from crashes. Vehicle crashes often delay other transportation system users. The magnitude of the impact depends on the location, time of day, physical extent, duration of crash investigation, and number of system users at the time the crash occurs and immediately after. By improving system safety and reducing the number of crashes that occur at a site or along a corridor, system users will avoid increased costs associated with the value of their time and decreased vehicle-operating costs. On the positive side, reduction in emissions and air quality improvements lead to health- related safety benefits. Health and safety are primary public responsibilities and health is begin- ning to be included in the safety mandate, to which DOTs also adhere. Economic Impact Analysis versus Cost-Benefit Analysis As discussed in Chapter 2, an EIA differs from a CBA in that a CBA evaluates the value of a project’s benefits and costs to society while an EIA considers a project’s impact on the economic activity within a locality or region. Common economic impacts include retail spending, tax revenues, jobs, and property values. EIAs typically evaluate only the positive impacts a policy or project has on a locality or region rather than the net effect. For example, an EIA will evaluate the positive impacts a transportation project has on one region, but will not take into account any adverse effects it might have on a neighboring region, nor does it consider the cost of the investment to the government (or other project sponsors). Emissions are a classic case of this discrepancy. Those living in less-desirable areas closest to high-traffic corridors also suffer the greatest health effects from emissions, controlling for other variables; people everywhere suffer from climate change impacts regardless of whether they drive and contribute to emissions through fossil fuel combustion.

Update to the Scenario The Virginia DOT evaluated the benefits associated with implementing adaptation strategies to increase the capacity of the culvert. They identified losses that would be incurred if none of the adaptation strategies is implemented. The losses include • Damage to physical structures, • Increased maintenance costs, • Debris removal and other disaster incidental costs, • System-user delays associated with road closures, and • Loss of fish habitat. A summary of the losses associated with the 100-year and 500-year events is included in Table 10. Some of these losses would be avoided if adaptation strategies were implemented under current conditions. Depending on the design level of protection, some residual damages could occur after the projects are implemented if the design level of protection is exceeded. The design level of effectiveness for climate- adapted conditions and the associated losses avoided are discussed in Chapter 7. Data needed at this stage include • Estimates of damages sustained from the hazard of concern, • Estimates of additional benefits resulting from the project, separated by physical, social, and environmental benefits if using multiple discount rates, and • Identification of any non-quantifiable benefits associated with the project. BENEFITS Benefit Data Input Event return period, Tc (years) 50 100 500 Associated return period, Tc Tcnd Tcmod Tcmax Associated flow, Qc 000,9)sfc( 10,505 13,982 Assumed level of damage to culvert (%) 0% 50% 100% -)trevluc(segamadlacisyhP $ 200,000$ 400,000$ -)daor(segamadlacisyhP $ 400,000$ 800,000$ -segamaDlacisyhP-latotbuS $ 600,000$ 1,200,000$ 000,3000,30 1100.0)sruoh(emitruoteD 02020selimlanoitidda-ruoteD -)yad/$(noitcnuffossolcimonocE $ 132,420$ 132,420$ 4170.0 -noitcnuFfossoL-latotbuS $ 926,940$ 1,853,880$ Clean up/debris removal -$ 60,000$ 120,000$ Traffic control -$ 10,000$ 20,000$ Casualties (injuries, loss of life) -$ -$ -$ Damages to vehicles -$ -$ -$ -segamaDrehtO-latotbuS $ 70,000$ 140,000$ -serca2-tatibahnomlasotsseccA $ 2,428$ 2,428$ -stcapmIlatnemnorivnE-latotbuS $ 33,508$ 33,508$ -)000,1(tnemtsujdAffodnuoR $ 1,630$ 3,227$ -)ffodnuoR(segamaDtnevElatoT $ 1,630,000$ 3,227,000$ DAMAGES BEFORE MITIGATION - SAME FOR ALL THREE PROJECT TYPES Traffic - one-way trips per day Duration of roadway loss (days) Table 10. Potential annualized losses for example scenario under current climate conditions without implementing adaptation options for the current 50-, 100-, and 500-year recurrence intervals using a 7 percent discount rate.

Next: Chapter 6 - Conducting a Cost-Benefit Analysis »
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Extreme weather events and a changing climate increasingly boost costs to transportation agencies and to the traveling public. While Departments of Transportation (DOTs) are taking into account changing climate and extreme weather when making infrastructure decisions, they typically are not using a formal set of tools or cost-benefit analyses (CBAs) to address climate resilience because they may be too time-consuming and expensive to conduct routinely.

The TRB National Cooperative Highway Research Program's NCHRP Research Report 938: Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change—Guidebook was developed to try to fill the gaps identified by DOTs. It is intended to provide a consolidated resource for transportation practitioners to be able to more readily consider CBAs as a tool in their investment-decision making processes when considering different climate and extreme weather adaptation alternatives.

This report has additional resources, including a web-only document NCHRP Web-Only Document 271: Guidelines to Incorporate the Costs andBenefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change, a Power Point presentation that describes the research and the results, a spreadsheet tool that provides an approximate test to see if it would be cost-effective to upgrade assets to the future conditions posed by climate change, and a spreadsheet tool that uses existing conditions without climate change only to calculate the new return period for future conditions with climate change.

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