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16 CHAPTER 2 Application of Freight Emissions This chapter documents the ways that freight transportation 2.1.1 EPA GHG Inventory emissions are applied to support decisions on public policy, infrastructure investments, and transportation system opera- Freight transportation is a significant contributor to U.S. tions. A solid understanding of how freight emissions estimates GHG emissions, contributing 26% of transportation GHG are used is necessary in order to assess the uncertainties and emissions and 7% of total U.S. GHG emissions in 2005. potential sources of error in the emissions estimation process. (1) These emissions are reported in the official EPA GHG In many cases, freight emissions estimates are prepared in Inventory, which is prepared annually by the EPA. Preparation response to federal or state regulations. These include the of the inventory fulfills the U.S. commitment as a signatory National Environmental Policy Act (NEPA) and similar state to the United Nations Framework Convention on Climate laws, the Clean Air Act and National Ambient Air Quality Stan- Change. dards (NAAQS), and federal conformity regulations. In other The EPA GHG Inventory reports six primary GHGs cases, freight emissions estimates are used in non-mandatory identified by the IPCC; three of these--CO2, N2O, and CH4-- studies that serve to educate stakeholders and guide government are produced by, and reported for, the transportation sector. programs or policy. The GHG inventory reports these emissions by year (going Freight emissions estimates are used in several basic ways. back to 1990), fuel, and vehicle type. Some of the fuel/vehicle In some instances, the emissions estimates themselves are categories encompass entirely freight sources (e.g., medium- reported and used by stakeholders to inform decisions. In other and heavy-duty trucks); others encompass both freight and cases, emissions estimates are fed into air quality dispersion nonfreight sources (e.g., rail, commercial aircraft). models, which then may feed exposure estimates and health As a complement to the EPA GHG Inventory, EPA has also risk assessments. In many applications, freight emissions are conducted studies that examine transportation GHG emissions combined with emissions from other mobile sources, or even in greater detail, including an examination of trends for each with point and area sources, before they are processed and mode and projections. (12) Another EPA-sponsored research reported. In these cases, the impact of the freight component study examined the causes for the rapid increase in freight- of the emissions on the ultimate decision may not be clear. related GHG emissions since 1990. (13) The set of applications described in this section is by no The purpose of the National GHG Inventory is to provide means comprehensive. The applications included in this a common and consistent mechanism for all nations to estimate section are intended to be the most common and prominent, emissions and compare the relative contribution of individual but the use of freight emissions estimates is almost limitless. sources, gases, and nations to climate change. The EPA GHG Inventory and complementary studies do not directly affect decisions regarding public policy or infrastructure investment. 2.1 National- and State-Scale The studies do influence federal programs, however, including Applications EPA programs targeting the freight sector. For example, in National- and state-scale applications of freight emissions the early part of this decade, EPA used inventory data to include GHG estimates as part of the EPA GHG Inventory (1) highlight the contribution of trucking to GHG emissions, which and state climate action plans, as well as national- and state-scale contributed to the development of the voluntary SmartWay studies of the health impacts of pollutant emissions. freight efficiency program.

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17 2.1.2 State Climate Action Plans compliance with reductions in future years. Approximately 20 states have established GHG reduction targets; to date, only Many states have estimated GHG emissions from freight California has mandated an economy-wide emissions cap that transportation as part of state climate change action plans. includes enforceable penalties. More than 30 states have developed climate plans. This process When individual mitigation strategies are analyzed, the typically starts with the development of a GHG inventory and estimate of freight emissions reduction is often done in a forecast for the state, using methods laid out in EPA's State relatively simplistic manner, given the time and resource Greenhouse Gas Inventory Tool. The inventory and forecast constraints on plan development. The estimation of emissions is an essential step in identifying effective GHG mitigation reduction and cost effectiveness could potentially influence a strategies. decision by the state to adopt a policy or implement a program. Following the inventory and forecast, freight emissions are To date, however, there are few examples of state climate action estimated when the benefits and costs of specific GHG mitiga- tion strategies are evaluated. Most state climate action plans plans leading to the adoption of GHG mitigation strategies include recommendations for one or two freight-focused miti- focused on the freight sector. Again, California is an exception, gation strategies. The most common are truck idle reduction, implementing or considering several regulations and programs truck fuel efficiency improvements, and freight mode shift to to reduce freight emissions pursuant to AB 32, Global Warming more fuel efficient modes. Solutions Act, mandating GHG reductions. (14) These efforts Like the EPA GHG Inventory, state climate plans estimate include the following: the six primary GHGs identified by the IPCC, and include three of these gases for freight sources: CO2, N2O, and CH4. Ship electrification at ports (adopted December 2007), Emissions of the three gases are combined to be reported in Ocean-going vessel speed reduction (proposed), terms of CO2 equivalent. Exhibit 2-1 shows a typical example Clean ship measure (proposed), of how transportation GHG emissions are presented in a state Port drayage truck rule (adopted December 2007), climate action plan. Commercial harbor craft educational program (proposed), In most states, the estimate of freight GHG emissions in the and state climate action plan does not directly influence public- or Expanded regulations on transport refrigeration units private-sector decision making. The state agencies or stake- (proposed). holder groups that develop recommendations for mitigation strategies may refer to the inventory and forecast as a way to In these instances, the estimation of GHG impacts is a key identify those strategies with the largest potential benefit. In factor in the state's decision to pursue these measures. reality, however, the selection of mitigation strategies typically is based on which strategies are thought to be feasible and 2.1.3 National- and State-Level cost effective, not on which sources contribute the most to Health Risk Assessments the state's emissions. In states that have mandatory GHG reduction require- EPA has sponsored numerous studies of the public health ments, the emission inventory will be critical for determining effects of air pollution. Many of these studies begin with esti- Exhibit 2-1. Example state transportation GHG emissions by source type, 19902020. 60 Other GHG Emissions, MMTCO2e 50 Rail 40 Boats and Ships-Offshore 30 Boats and Ships- 20 Ports/Inshore 10 Jet Fuel/Av. Gas 0 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020