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Representing Freight in Air Quality and Greenhouse Gas Models (2010)

Chapter: Chapter 5 - Recommended Research Areas

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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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Suggested Citation:"Chapter 5 - Recommended Research Areas." National Academies of Sciences, Engineering, and Medicine. 2010. Representing Freight in Air Quality and Greenhouse Gas Models. Washington, DC: The National Academies Press. doi: 10.17226/14407.
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141 This chapter provides five recommended areas for research that offer great promise for improving freight emissions estimates. Although these five research statements are mode- specific, the link between modes can be addressed with the implementation of the Conceptual Model. Each of these areas will improve the Conceptual Model and modeling of these modes in general. The descriptions of these research areas have been written as research statements with sections describing background, objectives, description of tasks, and funding requirements. This will provide the basis for NCFRP to develop statements of work and requests for pro- posals for future work. 5.1 Improving the Allocation of National Transportation Emissions Background The transportation sector accounts for a large portion of the nation’s emissions inventory, resulting in significant local health and public welfare impacts as well as nation- wide greenhouse gas emissions (GHGs). These emissions are the subject of public policy at the national, state, and local levels, in which regulatory agencies and industry organiza- tions work together to minimize transportation emissions in a cost-effective manner. Calculations of both the current emissions impacts and the benefits of mitigation strategies rely on the accurate allocation of national emissions esti- mates to individual geographic regions, transportation modes, and vehicle types. On the national scale, criteria air pollutant (CAP) and hazardous air pollutant (HAP) emissions are calculated by the EPA in the National Emissions Inventory (the NEI), (2) which is completed every 3 years. The NEI provides emissions data on the county level by SCC, representing the on-road, nonroad, locomotive, marine, and air transportation modes, as well as subcategories within each mode. In addition, nationwide GHG emissions are calculated by EPA in the Inventory of U.S. Greenhouse Gas Emissions and Sinks (the EPA GHG Inventory) annually. (1) This study allocates GHG emissions to each sector of the economy, including transportation, and within the transportation sector allocates emissions to each transportation mode, including on-road and nonroad vehicles, locomotives, aircraft, and marine vessels. Additionally, for several modes including on-road vehicles, the GHG Inventory further divides emissions by vehicle type. The allocations are based on share of fuel consumption and fuel type. For both the NEI and the GHG Inventory, the method- ology used to allocate emissions varies by mode, depending on available data sources. In some modes, such as rail, the NEI uses a “top-down” methodology, in which national- level fuel consumption data are allocated to specific regions and modes, in proportion to a measure of activity level. Calculations for other modes, such as on-road and non- road, rely on a “bottom-up” methodology, in which activity data reported on the county level are aggregated and modeled using the National Mobile Emissions Model (NMIM), with resulting emissions allocated to each region. The EPA GHG Inventory methodology uses both top-down and bottom-up approaches simultaneously, in which a top-down calcula- tion of fuel consumption by sector and mode based on fuel statistics is reconciled with a bottom-up modal analysis of fuel consumption by industry activity measures. Although the NEI focuses on regional allocation and the EPA GHG Inventory focuses on modal allocation, the accuracy of both methodologies depends on the quality of regional and activity data and the allocation method used, which vary across modes. There are both known and unknown limitations to the data used for regional and modal allocation, leading to uncertainty in the resulting emissions allocations. Research is needed to determine the sources and magnitude of uncertainty in emissions allocation, and to develop more accurate methods C H A P T E R 5 Recommended Research Areas

and data sources for allocating national transportation emis- sions by region. This research statement builds on prior work completed by the Transportation Research Board and other regulatory agencies. The analysis of data sources continues research com- pleted by transportation sector (such as this effort) and mode (ACRP Report 11: Guidebook on Preparing Airport Greenhouse Gas Emissions Inventories). (37) EPA has analyzed transportation emissions in depth, both in terms of GHG inventories (3) and in terms of evaluating uncertainty in emissions results. (195) The subjects and results of this research may impact agencies at the national, state, and regional level. The NEI is conducted by the EPA Office of Air Planning and Standards. The GHG Inventory is conducted by the EPA Climate Change Division of the Office of Atmospheric Programs. Emissions of CAPs and hazardous air pollutants (HAPs) within transportation modes are regulated by EPA in nonattainment areas (NAAs) and in state implementation plans. Finally, transportation-related GHG emissions are under analysis by several state DOTs either for inventory or policy purposes. Objectives The objective of this research is to analyze current methods and data sources for allocating national CAP, HAP, and GHG emissions by region and mode, and to identify opportunities for improving the accuracy of such allocations. To thoroughly evaluate the issues involved, this research will include a review of sources of uncertainty in the data and methodologies used, an evaluation of the magnitude of uncertainty in regional emissions inventories, and an identification of improvements to minimize uncertainties in regional emissions estimates. Finally, since the GHG Inventory allocates emissions by mode but not region, the research will analyze potential methods to allocate regional GHG emissions. The research and results should span pollutant types including CAP, HAP, and GHG, as well as transportation modes including on-road, nonroad, locomotive, marine, and aircraft. Description of Tasks Task descriptions are intended to provide a framework for conducting the research. NCFRP is seeking the insights of proposers on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers’ current thinking in sufficient detail to demonstrate their under- standing of the issues and the soundness of their approach to meeting the research objective. Task 1: Conduct Kick-Off Call Conduct a conference call with the panel 30 days after con- tract initiation to discuss the revised work plan developed in response to the panel review of the research plan in the agency’s original proposal. Task 2: Describe the Current Methodologies Describe the current methodologies used to allocate national emissions to regions and transportation modes. Identify sources of uncertainty in data sources and methodologies used in allocation. Task 3: Analyze the Limitations of Current Methodologies Building on Task 2, describe the limitations of current allo- cation methods, and evaluate the magnitude of uncertainty both in the data and methodologies used to allocate emissions to the regional level. Submit an interim report to the panel describing the results of Tasks 2 and 3. Task 4: Identify Options for Reducing Uncertainty Identify and evaluate options for reducing uncertainty and increasing accuracy in regional and modal emissions estimates by pollutant and transportation mode. The analysis of options should include the extent of data or modeling requirements, the ease or complexity of data collection, and any institutional or industry barriers to implementing the proposed strategy. Recommend opportunities for strategy implementation that would reduce uncertainty in regional emissions estimates con- sidering budget and time constraints. Task 5: Analyze Allocation Strategies Analyze strategies for extending the allocation of GHG emissions to the state and regional level, with consideration of accuracy and implementation issues. Task 6: Prepare Final Report Prepare a final report providing the results of the entire research effort. Funding Requirements A funding level of $200,000 is allocated to this research. The contract will be completed within 12 months of accept- ance of proposal, including 1 month for NCFRP review and 142

approval of the interim report and 1 month for NCFRP review and contractor revision of the final report. It is anti- cipated that the research will not require fieldwork, labo- ratory testing, or travel in addition to meetings with the project panel. 5.2 Refining Road Project-Level Emission Estimates Methodologies Background Previous research has indicated the importance of accurately reflecting the effects of local parameters on vehicle emissions, especially at the project or corridor level. These parameters can include road grade, road capacity, congestion, and vehicle aerodynamic coefficients, among others. Although there have been many advances in methodologies to capture such effects, there still is no clear guidance on the best methods for different types of applications. With the release of the final version of MOVES, scheduled for the end of 2009, EPA is indicating that MOVES will be the required model for SIP and conformity analyses. However, it is unclear how MOVES should be utilized for project-level analyses. MOVES employs a “modal” emission rate approach as a prelude to finer-scale modeling. It relies primarily on sec- ond-by-second vehicle emissions data to develop emissions rates, and better represents the physical processes from ve- hicles, including the ability to model cold starts and ex- tended idling, which is especially critical for heavy-duty trucks. Although the modal approach taken by MOVES seems appropriate to capture some local impacts, other tools, such as the Comprehensive Modal Emissions Model, devel- oped by UC Riverside under an EPA contract, provide a more direct and transparent way to account for factors such as vehicle aerodynamics, pavement quality, and road grade. As a result, it is unclear as to whether it will the best tool for all applications, or how local traffic and vehicle data will need to be collected for use in MOVES or other applicable emission models. Although this research does not strictly apply to heavy-duty trucks, the evaluation of truck emissions would greatly benefit from this research project. Despite the fact that some trucks can avoid congestion by traveling during off-peak times, congestion is expected to worsen over time. Thus, the trend is that trucks will become more affected by congested roadways in the future. Additionally, voluntary programs such as EPA’s SmartWay, have been advocating for the use of devices that improve either aerodynamic coefficients or rolling resistance coefficients, and these parameters need to be properly captured in emission calculations. Objectives This research aims to address the following objectives: • Determine the best methods/models to capture the effects of local traffic and vehicle parameters on vehicle emissions for different types of application and • Determine how to best capture local traffic activity and local vehicle characteristics for use in different emission models. Description of Tasks Task descriptions are intended to provide a framework for conducting the research. The panel is seeking the insights of proposers on how best to achieve the research objectives. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of avail- able funds and contract time. Proposals must present the proposers’ current thinking in sufficient detail to demonstrate their understanding of the issues and the soundness of their approach to meeting the research objective. Task 1: Conduct Kick-Off Call Conduct a conference call with the panel within 30 days after contract initiation to discuss the revised work plan developed in response to the panel review of the research plan in the agency’s original proposal. Task 2: Review Effects of Local Parameters on Vehicle Emissions Conduct a brief literature review on the effects of local parameters on vehicle emissions, aiming at selecting a list of parameters that should be included in the research (i.e., those with the most substantial effects on vehicle emissions). At a minimum, congestion, road grade, and vehicle aerodynamics should be considered. Other parameters such as pavement quality could also be included. Task 3: Determine Accuracy Needs and Limitations Determine the accuracy requirements and limitations for emissions analyses that aim at capturing the effects of local parameters on vehicle emissions. This research needs to be framed by accuracy requirements. On one end of the spectrum, accuracy requirements for air quality analyses and emission estimation need to be determined. This will guide the selection of appropriate methods to quantify the effects of local parameters on emissions. At the other end 143

of the spectrum, the limitations of methods (data collection, traffic modeling, emission modeling) need to be assessed. In other words, the right balance between how accurate methods should be and how accurate methods can be needs to be achieved. This task will also consider the different types of applications that might require the evaluation of effects of local parameters on vehicle emissions. For example, projects that add road capacity, improve traffic operations, or manage travel demand could have impacts on road congestion, and consequently on vehicle emissions. It will be important to consider these dif- ferent applications when evaluating accuracy requirements and limitations. Task 4: Evaluate Current Methods Conduct an evaluation of current methods to capture the effects of local parameters on emissions, including the tradeoffs between accuracy and data limitations. Current methods to evaluate congestion effects can be roughly divided into three types: (1) speed correction factors, (2) customized driving cycles, and (3) vehicle-specific power. Currently MOBILE6 and EMFAC estimate the effects of congestion on emissions by using speed correction factors that differentiate emission factors by average speed. Previous research has indicated that this method might work reason- ably well for uncongested freeways but it is ill-suited to assess the congestion effects on arterials and local roads or on con- gested freeways. The use of modal emission models such as CMEM can provide a more accurate representation of the effects of congestion on emissions, but they rely on the devel- opment of customized driving cycles that depend on heavy data requirements, and might not be representative of driving conditions other than those for which they were originally developed. Somewhere in between are methods such as those proposed by MOVES, where a binning approach could pro- vide a more accurate representation of driving conditions by assigning the share of time in each combination of speed range and vehicle-specific power. However, it is uncertain how local input driving parameters will be used to feed into the binning approach. New methodologies need to be developed and tested to bridge the gap between traffic data availability and emis- sion methodologies that provide an accurate representation of congestion. Regarding other parameters such as road grade and vehicle aerodynamic coefficients, some models can consider them explicitly (CMEM), while others (MOVES) might require additional steps to convert these parameters into modified vehicle-specific power estimates. This research should exam- ine the feasibility and levels of effort and technical expertise required to make such conversions, and describe whether the conversions would yield accurate estimates of the effects of such parameters on vehicle emissions. Task 5: Provide Interim Report Provide an interim report to panel members summarizing the findings from Tasks 2, 3, and 4. Panel members would review the report and provide supporting concurrence and/or recommendations for additional data gathering as needed. Task 6: Improve Methods to Model Traffic Activity Task 6 will improve the methods to model traffic activity to reflect congestion impacts on vehicle emissions more accurately. This will be accomplished by (1) the development of new con- gestion metrics that can be used in emissions calculations and (2) the development of new methods for traffic data collection to gather the right type of information for emissions calcula- tions, including information on vehicle mix. The modeling of traffic activity needs to be conducted in such a way that it fulfills the needs of emissions and air quality analyses that aim to incorporate the effects of congestion. In such a context, traffic modeling relies on three elements: congestion modeling, traffic data, and vehicle configuration. Congestion has traditionally been represented in terms of road level of service (LOS) or total vehicle delay, and there are concerns about the use of such metrics as inputs in emissions models. LOS is a discrete measure of traffic conditions, while the estimation of emissions depends on continuous variables. Although LOS can be represented by an “average” driving cycle, there are criticisms associated with representing a level of service by a single driving cycle, given that an LOS represents a wide variety of traffic conditions. As a result, there is a need to develop new congestion metrics that can be used in emissions estimation. Traffic data need to be collected in a way that enables the calculation of such new congestion metrics. The basic concepts of traffic theory, which model traffic based on traffic flow, traffic density, and average speed, currently determine traffic data collection processes. New methods for traffic data collec- tion need to be developed and implemented to gather the right type of information for emissions estimation. For example, new technologies (e.g., GPS, cell phones) can collect traffic data in real time, and methods to aggregate traffic data could both protect drivers’ privacy and provide the appropriate inputs for emission models. The VMT share by vehicle type is a key input to emission models, but information on vehicle type is rarely collected on site. Instead, it typically relies on vehicle registration data, which can be a poor proxy for local traffic mix, especially for heavy-duty trucks. With the requirements of emission models 144

in mind, new methods could be developed to capture data on traffic mix. Task 7: Evaluate Methodologies for Local Data Collection Task 7 will evaluate different methodologies to collect local data, including traffic data, infrastructure data (e.g., road grade, pavement quality), and vehicle characteristics data (e.g., aerodynamics). The use of GPS devices could provide enough information for the development of real-time driving cycles, which could be linked with modal emission models for emissions estimation on a second-by-second basis. GPS devices could also transmit vehicle information for proper characterization of fuel type, engine and transmission characteristics, and vehicle gross vehicle weight rating (GVWR). Road grade information can be obtained by superimposing such driving cycles with grade information for relevant road networks. Task 8: Prepare Final Report Task 8 will compile the results from previous tasks in a clear and concise document that will serve as support for future emissions analyses. Funding Requirements A funding level of $200,000 is allocated to this research. The contract will be completed within 12 months of acceptance of proposal, including 1 month for review and approval of the interim report and 1 month for review and contractor revision of the final report. It is anticipated that the research will not require fieldwork, laboratory testing, or travel in addition to meetings with the project panel. 5.3 Improving Rail Activity Data for Emission Calculations Background Current practice for estimating freight rail emissions is often based on EPA’s methodology, which relies on fuel consumption data to determine emissions. Detailed fuel consumption data are typically considered sensitive information by railroads. However, aggregate fuel consumption data, which are based on 100% reporting for Class I railroads, are available from industry or government agencies (i.e., Association of American Railroads, Energy Information Administration, state agencies, private companies via surveys). Streamlined, or “top-down,” methods determine emissions based on publicly available data on fuel consumption at the national or state level, and apportion emissions to the state or county level using an available activity metric, such as traffic density or mileage of active track. Detailed, or “bottom-up,” methods calculate fuel consumption either by measuring freight movements or surveying individual railroad companies. Typically, there is little or no published information on railroad activity available for a specific region. Thus, state and regional air quality agencies must obtain railroad activity data directly from the railroad companies. Objectives The objective of this research project is to improve rail activity data for emission calculations through the develop- ment of alternative methods for railroad data reporting and the comparison of different methods to disaggregate rail fuel consumption data. Description of Tasks Task descriptions are intended to provide a framework for conducting the research. The panel is seeking the insights of proposers on how best to achieve the research objectives. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers’ current thinking in sufficient detail to demonstrate their under- standing of the issues and the soundness of their approach to meeting the research objective. Task 1: Conduct Kick-Off Call Conduct a conference call with the panel within 30 days after contract initiation to discuss the revised work plan developed in response to the panel review of the research plan in the agency’s original proposal. Task 2: Develop Alternative Methods for Railroad Data Reporting Three factors drive the need for new methods of railroad fuel data reporting. First, there are large uncertainties associ- ated with the use of aggregated fuel data for regional and local emission analyses. Second, disaggregated data can only be obtained directly from the railroads. Because of concerns about releasing sensitive information, railroads are sometimes reluctant to share detailed operational activity. Third, there are concerns about the accuracy of county-level gross ton-miles data provided by the railroads. As a result, this task should (1) examine the concerns presented by railroads, (2) deter- mine the most critical information necessary to improve the 145

accuracy of emission estimates, (3) determine the most effective ways to increase the cooperation between public agencies and private railroads, and (4) develop new methods for collecting railroad data. Task 3: Compare Methods to Disaggregate Rail Fuel Consumption Data Many regional and local emission analyses rely on different methods to disaggregate rail fuel consumption data. Depend- ing on the chosen method, high levels of uncertainties are involved, and this task will determine how such methods can be improved through the collection of local and regional data. The research should consider the tradeoffs between improved accuracy and additional resources needed to col- lect and report local and regional data. Task 4: Prepare Final Report Compile the results from previous tasks in a clear and concise document that will serve as a support for future rail emissions analyses. Funding Requirements A funding level of $100,000 is allocated to this research. The contract will be completed within 12 months of acceptance of proposal. It is anticipated that the research will not require fieldwork, laboratory testing, or travel in addition to meetings with the project panel. 5.4 Improving Parameters and Methodologies for Estimating Marine Goods Movement Emissions Background Numerous issues arise in the calculation of emissions at and near marine transport and goods movement terminals. Emissions at these port areas include activity from ocean-going vessels (OGVs), commercial and non-commercial harbor craft (H/C), and cargo handling equipment (CHE). Each mode has unique calculation methodologies and input data, as well as resulting uncertainties. Emissions from marine goods movement are a significant share of the nation’s total freight emissions. For example, the EPA GHG Inventory estimated that 14% of the nation’s 2005 total freight transportation-related CO2 emissions are due to domestic waterborne commerce alone. The share of other pollutants is likely to be higher given the relatively uncontrolled emissions from this sector. At a global scale, the marine trans- port sector emits 1.2–1.6 million metric tons (Tg) of PM10, 4.7–6.5 Tg of SOx, and 5–6.9 Tg of NOx annually. That is, approximately 15% and 5%–8% of global NOx and SOx emissions, respectively, are attributable to ocean-going ships, and approximately 60,000 annual cardiopulmonary and lung cancer deaths are related to PM emissions from marine shipping. However, all emission estimates from marine shipping are uncertain. Current best practices in preparing individual port emission inventories have advanced considerably since the first attempts at quantifying national port-related emissions. Generally, there are insufficient data to confidently and quantitatively assess marine emission uncertainties. Although overall accuracy and uncertainty associated with different methods and models to estimate freight emissions are not generally quantified, sources of these uncertainties have been identified. For example, emissions from OGVs are usually determined at and around ports only, as these are the entrances and clearances of cargo into the regions of modeling interest, using informa- tion on number of calls at a particular port, engine power, load factors, emission factors and time in like modes. These data are often incomplete or of insufficient quality. Although a wide range of commercial harbor craft (H/C) operate in the vicinity of ports, many of these vessels serve purposes other than just direct goods movement and their activities and vessel param- eters are often unknown. The diversity of types, the number, and fleet parameters of CHE in use is related to the diversity and amount of freight handled at a port. Even in cases where cargo data are available, CHE data are often estimates. Further uncertainty arises when aggregating marine freight emissions regionally or nationally. For example, emissions at a national scale are computed in EPA’s National Emission Inventory (NEI) with a reliance on a combination of distinct methodologies for each source category and aggregation to the county level. Furthermore, data in the 2002 and 2005 NEI are based on an inventory of marine engines conducted in 1998. Emissions estimates appropriate at two scales—local and national—should be estimated and appropriately joined. To improve the emissions estimate from this critical sector of the nation’s freight transport infrastructure, these issues need to be addressed. Objectives The goal of the following objectives is to improve the esti- mation of emissions from marine freight-related (OGV, H/C, and CHE) activities near ports, and their impact on national emissions: • OGV – Develop updated and more accurate marine vessel emission factors and load factors, 146

– Improve information and emissions factors associated with auxiliary engines, and – Improve emission factors for methane, nitrous oxide, and black carbon. • H/C – Improve input parameters for HC emission estimation, especially emission factors and load factors. • CHE – Develop updated emission parameters for CHE engines, especially emission factors and load factors, and – Develop idling emission factors for CHE and idling time estimates. • National Scale – Conduct updated marine inventory for future NEI publications. The objective of this research statement is to address and implement these recommended changes. To best achieve this objective, the recommendations have been reorganized and distilled here into three primary objectives based on theme rather than source category. Each objective applies to several of the source categories active at ports. Objective 1: To Improve Emission Inputs for Marine and Port-Related Emissions Current OGV and H/C emission factors are still based on limited test data and provide only a rough estimate of emissions from newer vessels. Several new emissions test- ing programs funded by the California Air Resources Board, EPA, and Environment Canada, among others, have in- volved OGVs, H/C, and CHE. These new data need to be reviewed and compared against currently accepted emission factors. Results of this current testing of emissions should be compiled. Specifically for OGVs, PM emission factors for slow- and medium-speed engines need further review, evaluation of impact of previous emission factors, development of emis- sion factors specifically for PM2.5, and advancement in the ability to relate PM and SOX emissions to fuel sulfur level. Emission factors need to be improved for non CO2 GHGs, including methane, nitrous oxide, and black (elemental) carbon. Improved emission factors also are needed for incin- erators and boilers. In addition, emissions at low loads need to be examined since emission factors tend to increase rapidly when engine load drops below 20% maximum continuous rating (MCR). Current emission factors for CHE are based on limited test data, often for on-road engines, and need to be updated to represent emissions from the current fleet of CHE engines. Especially for CHE, emission factors should be developed that separate idling from active-engine emission factors. Better emissions input characteristics for other parameters also need to be developed. For OGV auxiliary engines and H/C, there is little consistent information on the number and size of the engines on vessels. Information needs to be developed including number, load factors, types of operation, and fuel used. Current H/C load factors differ from one another by a factor of two or more; this variance should be reduced by studies of H/C activity and engine load profiles. Separate pro- files need to be developed for in-port versus inland river cargo movements. Duty cycles for nonroad engines should also be examined more fully and selected to provide CHE-specific load factors. Objective 2: To Improve Modeling Methodologies for Port-Related Emissions There are numerous improvements that should be made to activity and other emission modeling parameters for OGV, H/C, and CHE. Data on vessel activity should be improved. For OGVs, domestic ship movements within the United States are currently not reported except in detailed inventories. H/C movement data at ports and on rivers also are generally not well documented. Additional data is needed for CHE activity profiles, specifi- cally as used at ports and incorporating idle time. A suggested method to estimate these activity data needs to be developed. Emission models should be improved to better estimate nonroad emissions. NONROAD will eventually be replaced by the MOVES model; it is unknown if OFFROAD will be similarly updated. Both should be improved to specifically handle CHE, H/C, and OGV engines, although MOVES should be able to calculate emissions at smaller spatial scales than either current model. Testing of the model is required once available. Objective 3: To Implement Advances to Update Regional/National Scale Estimates for Port-Related Emissions As advances are made in Objectives 1 and 2, they should be implemented to improve estimates in both local and regional/ national scale emission inventories. Typically, detailed inven- tories are made at the scale of individual ports and are scaled to other areas to estimate regional and/or national emissions. The advances in port emission inventory practices should be implemented first to improve local emission inventories. Simultaneously, national inventories should be updated that will incorporate the advances from Objectives 1 and 2. As more ports complete detailed emission inventories, guidance on port matching should be updated in order to better estimate emissions at small, poorly characterized ports. As this mapping between more and less detailed ports is developed and more ports produce updated, detailed emission inventories, the 147

calculation of national and regional marine emissions should be updated to reflect—not only changes in equipment type and number—but also changes in age distribution and usage (load factor) of CHE, H/C, and OGV at the port. This will result in a more comprehensive National Emission Inventory (NEI) for the marine freight sector. Description of Tasks Task descriptions are intended to provide a framework for conducting the research. NCFRP is seeking the insights of proposers on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers’ current thinking in sufficient detail to demonstrate their under- standing of the issues and the soundness of their approach to meeting the research objective. Task 1: Conduct Kick-Off Call Conduct a conference call with the panel within 30 days after contract initiation to discuss the revised work plan developed in response to the panel review of the research plan in the agency’s original proposal. Task 2: Conduct Literature Review Conduct a literature review and analysis to determine appropriate emission factors, load factors, duty cycles, and other parameters to represent the current fleet of engines used in CHE, H/C, and main, auxiliary, and boiler engines for OGV, and compare them to currently accepted factors. Task 3: Develop Activity Methodology Develop methodologies to estimate OGV, H/C, and CHE activities missing from current data sets. Once available, evaluate MOVES for performance in the marine sector. Task 4: Update Emission Inventories Update local scale marine freight emission inventories with best-practice data and methodologies. Develop enhanced port matching routine and update national marine-freight emission inventory. Task 5: Provide Interim Report Provide an interim report to panel members summarizing the findings from Tasks 2 and 3. Panel members would review the report and provide supporting concurrence and/or recom- mendations for additional data gathering as needed. Task 6: Prepare Final Report Prepare a final report providing results of the entire research effort. Funding Requirements A funding level of $250,000 is allocated to this research. The contract will be completed within 18 months of acceptance of proposal, including 1 month for review and approval of the interim report and 3 months for review and contractor revi- sion of the final report. It is anticipated that the research will not require fieldwork, laboratory testing, or travel in addition to meetings with the project panel. 5.5 Improving Air Freight Emission Calculations Background Demand for air freight transportation is projected to return to strong growth in North America in the near future. OAG Aviation projects an annual growth rate of 5.6% per year by 2011 and an overall international 10-year annual average growth rate of 6.1% over the period from 2008 to 2017. Although increased fuel efficiency from new aircraft will partially mitigate increased air freight emissions, it is not expected to fully offset greenhouse gas emissions (GHGs) and will have minimal reductions on particulate matter and NOx emissions. Current methods used to estimate air transportation emissions have focused on passenger aircraft because they are the major share of air transportation emissions. However, with the projected growth in air freight, the contribution of air freight needs to be more clearly determined, especially in light of the mixed-mode use of aircraft to move both pas- sengers and air cargo. Further, limited data exists on emission indices for air freight aircraft as well as air freight perform- ance data. Current tools used to assess environmental impacts from air transportation are FAA’s AEDT/EDMS. The focus to date has been with passenger aircraft, and default values have been developed with this as the basis. However, these default values may not always be appropriate for air cargo aircraft. Continued growth at major airports and regional hubs are leading to increased congestion and the use of alternative/secondary regional airports to avoid delays. This may include movement to airports mainly servicing air cargo needs. Nearby commu- nities may be impacted, particularly as these operations may 148

have significant activity during the nighttime period. Research is needed to clearly evaluate air freight emissions consistent with the knowledge level of air passenger aircraft as well as to develop a consistent scheme for allocating emissions associated with mixed air freight and air passenger operations. Better assignment of air passenger and air freight emissions will enable decision makers to make informed decisions about the impacts from future airport expansions for both air passenger and air cargo operations. The research will need to be incorporated into FAA models because these are used to evaluate air quality impact assessments as required in state implementation plans and environmental impact assessments. Coordination with FAA and EPA will be needed to ensure that the research results can be incorporated into the modeling tools, both in terms of analysis of the results and the quality of information gathered. Objective The objective of this research is to develop an improved basis for generating emissions associated with air freight trans- portation. The research should examine the current usage and assignments made specific to air cargo freight within EDMS and the future AEDT modeling system. Some, but not all of the assignments would include: (1) aircraft/engine combinations, (2) assumptions and basis for takeoff weight, (3) glide slope angle, (4) time in mode, and (5) disaggregation of freight emissions for air passenger emissions. The research should evaluate the appropriateness of the current assignment prac- tices, evaluate the limitations with the current approach, and provide recommendations for better assignments. The proposed project comes at a critical time when research garnered from this study could be incorporated into the current development of the AEDT 2.0 Modeling System. Current assignment practices for mixed-mode air freight and passenger mode are probably not representative of the air freight trans- portation contribution. It is likely that emission reduction targets near airports will be needed at many of the nationwide airports as they are, or soon will be, located in air quality nonattainment areas due to the recently revised 24-hour PM2.5 ambient air quality standard (65 µg/m3 lowered to 35 µg/m3) and the newly proposed 1-hour NO2 standard of between 80–100 ppb to be finalized by January 2010. Description of Tasks Task descriptions are intended to provide a framework for conducting the research. NCFRP is seeking the insights of proposers on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers’ current thinking in sufficient detail to demonstrate their under- standing of the issues and the soundness of their approach to meeting the research objective. Task 1: Conduct Kick-Off Call Conduct a conference call with the panel within 30 days after contract initiation to discuss the revised work plan developed in response to the panel review of the research plan in the agency’s original proposal. Task 2: Describe Current Methods Describe the current method used to estimate air freight emissions as implemented in EDMS. This would include details on the underlying assumptions, data sets used to support these assumptions and the extent to which the assumptions are justified, their relative importance, and the current limitations with the method and supporting databases. Task 3: Identify Data Needs For those data set or underlying assumptions that were identified as critical to improving the characterization of air freight emissions, provide recommendations on the additional data needed to support development of a more robust data set to better characterize freight emissions. This could include both activity data as well as emission indices. Task 4: Provide Interim Report Provide an interim report to panel members summarizing the findings from Task 2 and Task 3. Panel members would review the report and provide supporting concurrence and/or recommendations for additional data gathering as needed. Task 5: Conduct Additional Data Gathering Conduct additional data gathering as reached in discussion with panel members. This could include gathering existing data sets for further analysis or additional data gathered from field studies. Analyze the data for use in support of the EDMS/AEDT Modeling System. Task 6: Develop Methodology for Disaggregating Freight Emissions Develop an improved methodology for disaggregating freight emission fractions between air freight and air passengers when a plane operates in mixed mode. Include characterizations of 149

potential impacts on time in mode, engine performance, and takeoff weight. Task 7: Address Air Cargo Issues in AEDT Model Development Currently, development of FAA’s AEDT lacks participation from the air freight community. This effort is being sponsored by FAA using supporting contractors and the academic com- munity. External oversight and guidance are provided on a once per year basis as part of the Design Review Group. Actively participate in at least one, and preferably two, stakeholder meetings as a representative of the air freight community to assure that issues relevant to air cargo transport are addressed as part of the model development process. Task 8: Determine Impact of New Aircraft Technology in Modeling Methodology New aircraft technology including very light jets (VLJs) and unmanned aerial vehicles (UAVs) will be used increasingly in future air freight transportation, particularly UAVs, in an effort to reduce labor costs. Identify how these technologies will change aircraft operations such as takeoff weight, glide slope, and emission indices, and the resulting likely change in air freight emissions. Task 9: Prepare Final Report Prepare a final report providing results of the entire research effort. Funding Requirements A funding level of $150,000 to $200,000 is allocated to this research. The contract will be completed within 18 to 24 months of acceptance of proposal, including 1 month for review and approval of the interim report and 1 month for review and contractor revision of the final report. It is anticipated that the research will not require fieldwork, laboratory testing, or travel in addition to meetings with the project panel. The budget depends upon the additional data gathering effort involved in Task 5. The low-end estimate assumes exist- ing data are available from the literature to support the analysis, while the high-end estimate allows for the need to collect field data in the case that published data are not available. 150

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TRB’s National Freight Cooperative Research Program (NFCRP) Report 4: Representing Freight in Air Quality and Greenhouse Gas Models explores the current methods used to generate air emissions information from all freight transportation activities and their suitability for purposes such as health and climate risk assessments, prioritization of emission reduction activities, and public education.

The report highlights the state of the practice, and potential gaps, strengths, and limitations of current emissions data estimates and methods. The report also examines a conceptual model that offers a comprehensive representation of freight activity by all transportation modes and relationships between modes.

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