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Environmental Assessment of Air and High-Speed Rail Corridors (2013)

Chapter: Chapter Seven - Unifying Frameworks

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Suggested Citation:"Chapter Seven - Unifying Frameworks ." National Academies of Sciences, Engineering, and Medicine. 2013. Environmental Assessment of Air and High-Speed Rail Corridors. Washington, DC: The National Academies Press. doi: 10.17226/22520.
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Suggested Citation:"Chapter Seven - Unifying Frameworks ." National Academies of Sciences, Engineering, and Medicine. 2013. Environmental Assessment of Air and High-Speed Rail Corridors. Washington, DC: The National Academies Press. doi: 10.17226/22520.
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Page 27
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Suggested Citation:"Chapter Seven - Unifying Frameworks ." National Academies of Sciences, Engineering, and Medicine. 2013. Environmental Assessment of Air and High-Speed Rail Corridors. Washington, DC: The National Academies Press. doi: 10.17226/22520.
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Page 28

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26 chapter seven UNIFYING FRAMEWORKS LCA, impact assessment, and benefit-cost analysis are some- times used to produce unifying analytical boundaries and metrics for comparing air and HSR systems. These frame- works produce common footings by which the net social costs of long-distance transportation services can be assessed. LIFE-CYCLE ASSESSMENT Most environmental assessments focus on vehicle operation and propulsion; however, there has been a recent emergence of studies that quantify the life-cycle effects by including vehicle, infrastructure, and energy production components. Environmental LCA approaches have been used for U.S. transportation systems assessment since the mid-1990s (Lave et al. 1995; MacLean and Lave 1998) and recently have been applied to air and HSR systems for environmen- tal comparisons (Network Rail 2009; Chester and Horvath 2010, 2012). LCAs of air and HSR systems can include vehicles (manufacturing and maintenance), infrastructure (construction, operation, and maintenance), and energy pro- duction (primary fuel feedstock extraction, processing, and distribution) components. LCA studies tend to capture either all components (Chester and Horvath 2010, 2012) or strictly infrastructure construction effects (Chang and Kendall 2011), in addition to vehicle operation and propulsion. There are several LCA studies that focus exclusively on the con- struction impacts of HSR (Thiebault 2010; Åkerman 2011; Chang and Kendall 2011), whereas other studies consider only vehicle operation and propulsion (Givoni 2007; Scott 2011). LCA results for California’s air and HSR systems show that (1) for air, life-cycle components can increase the mode’s footprint by roughly 20%, and (2) for HSR, concrete and steel used in infrastructure construction may double the GHG footprint of the mode (Chester and Horvath 2012). In Figure 4, life-cycle GHG emissions (per passenger-mile traveled) for long-distance modes in the California corridor from Chester and Horvath (2012) are shown. The life-cycle results contrast operation (gray) and propulsion (light green) GHG emissions against vehicle (manufacturing and mainte- nance), infrastructure (construction, operation, and mainte- nance), and feedstock energy (raw primary fuel extraction, processing, and distribution). Emissions from infrastructure construction may be offset by reductions in automobile man- ufacturing, roadway construction, and airport construction in the long run (Åkerman 2011). Wang and Sanders (2011) use economic input-output LCA methods to estimate that Florida HSR construction will have significantly lower energy and GHG effects than that of California because of heavy engi- neering requirements in California, particularly in structure work. Sustainability trade-offs between future air and HSR systems should connect environmental perturbations with their human health, ecosystem services, resource depletion and climate change impacts where possible. Over the past half century, significant research and efforts have been made by the aviation industry and academics to understand the human health impacts of near-airport operations (Bastress 1973; Westerdahl et al. 2008; Hu et al. 2009). As questions emerge about the trade-offs of air and HSR systems, it will be important to define “sustainability” in its broadest sense (instead of strictly GHG emissions) to understand environ- mental benefits or unintended trade-offs. Although GHG emission comparisons are critically important, it is also important that future studies consider other air emissions (in particular CAP emissions) as well as the environmental con- cerns identified by NEPA. By defining sustainability broadly, opportunities will exist for understanding how the reduction in one environmental concern may lead to a reduction in another, or reduction in one environmental concern may lead to an increase in another (i.e., an unintended trade-off). By identifying unintended trade-offs early in the planning pro- cess, more opportunities will exist for implementing mitiga- tion strategies. The summary of studies shown in Table A1 reveals a heavy interest in energy and GHG analysis, and only one comparative study was identified that connects air emissions to human health and ecosystem services impacts (Chester and Horvath 2012); that study evaluates GHG emis- sions and the potential for human health respiratory impact, acidification, eutrophication, and photochemical smog for- mation trade-offs in future long-distance travel in California. Existing research can aid in classifying the many sustain- ability impacts that can be considered beyond the standard NEPA criteria considered in EIRs and EISs. Few studies have attempted to quantify the human health, ecosystem ser- vices, and resource depletion impacts outside of GHG effects. Although not all impacts will be relevant or of interest to dif- ferent stakeholders, it is critical to understand the interrela- tion of pollutants. The quantification of pollutant trade-offs is valuable; however, ultimately a more rigorous understand- ing is needed of the impacts these pollutants cause with their release in particular geographic areas.

27 BENEFIT-COST ANALYSES Defining an HSR cost model presents a unique set of chal- lenges compared with the aircraft cost model development. Currently there are no HSR systems in the United States from which to collect cost and operating statistics. Although there are many HSR systems across the world, publicly available data are limited and not available in a consistent format. For example, many HSR operators present their operating sta- tistics in annual reports, yet these statistics may be aggre- gated with conventional rail operations. Campos and de Rus (2009), in a comprehensive study of HSR system costs and HSR modeling techniques, note the challenge of compar- ing (and therefore modeling) costs across HSR systems. Because HSR projects are built over various topographical landscapes, different technical solutions and levels of invest- ment are needed. This is unlike the air mode, for which one can model aircraft costs with some level of consistency. Although some studies have attempted to quantify the economic benefits Impact assessment practitioners in LCA have identified and categorized broad suites of human health, ecosystem quality, climate change, and resource depletion concerns, and air and HSR system decision makers can use this research to aid in the environmental assessment of their systems. Table 3 shows the categorization of pollutants into midpoint categories that are then aggregated to damage categories. For example, several midpoint categories produce human health impacts and Jolliet et al. (2003) advocate that these midpoint categories can be joined after impacts are normalized to disability adjusted life-years to obtain a comprehensive assessment of human health impacts. Life-cycle impact assessment methods generally focus on physical pollutants and do not include characterization methods for many of the NEPA criteria. However, the meth- ods developed provide a framework upon which air and HSR environmental assessment practitioners can begin joining the many indicators that are of interest for future decisions. FIGURE 4 Life-cycle GHG emissions per passenger-mile traveled. (Source: Chester and Horvath 2012.) Emissions to impacts (note: RPS electricity is the U.S. regulatory Renewable Portfolio Standard that requires the increased production of energy from renewable energy sources, such as wind, solar, biomass, and geothermal). Midpoint Category Damage Category Po llu ta nt s Human toxicity Human health Respiratory (inorganics) Human health Ionizing radiation Human health Ozone layer depletion Human health Photochemical oxidation (respiratory organics) Human health/Ecosystem quality Aquatic ecotoxicity Ecosystem quality Terrestrial ecotoxicity Ecosystem quality Terrestrial acidification/Nutrification Ecosystem quality Aquatic acidification Ecosystem quality Aquatic eutrophication Ecosystem quality Landoccupation Ecosystem quality Globalwarming Climate change Non-renewable energy Resource depletion Mineral extraction Resource depletion Adapted from Jolliet et al. 2003. TABLE 3 MIDPOINT AND DAMAGE CATEGORIES FOR ENvIRONMENTAL ASSESSMENT PRACTITIONERS

28 of air travel, similar HSR benefits to a region are not clear. The costs of U.S. HSR systems have been of interest as regions attempt to understand the investments and operating com- mitments that will be needed to maintain service; however, the economic benefits of that service are not well understood. Benefit-cost analyses of air and HSR systems sometimes include monetization of environmental impacts (Levinson et al. 1997; Janic 2003; Givoni 2007; Adler et al. 2010; Rus 2011) (see Figure 5). Adler et al. (2010) develop social wel- fare functions that include environmental externalities to assess transportation infrastructure investments and their effects on transportation equilibriums. They find that the European Union should include HSR development in future long-distance trans- portation investment to maximize social welfare. Rus (2011) develops a framework that includes monetized externalities to evaluate the conditions under which investment in HSR proj- ects are justified. Givoni (2007) computes the environmental benefits of mode substitution for air and HSR by estimating the aircraft, access/egress, aircraft journey, and HSR journey air pollution externalities per seat between London and Paris. Givoni finds that the external costs of travel on HSR are 0.52 Euros per seat and on air are 1.03 Euros per seat. Janic (2003) monetizes air emission externalities and evaluates that the marginal costs of HSR travel are generally lower than those of air travel in Europe but does not assess the total costs of each system. FIGURE 5 Givoni (2007) outlines the steps leading to the monetization of environmental impacts. At each stage, addi- tional uncertainty is introduced, decreasing the level of scientific understanding and increasing subjectivity.

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TRB’s Airport Cooperative Research Program (ACRP) Synthesis 43: Environmental Assessment of Air and High-Speed Rail Corridors explores where additional research can improve the ability to assess the environmental outcomes of these two systems.

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