Guidebook for Quantifying Airport Ground Access Vehicle Activity for Emissions Modeling (2017)

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2Introduction and Background This guidebook was developed as part of ACRP Project 02-63, “Quantifying Airport Ground Access Vehicle Activity for Emissions Modeling.” The guidebook provides a set of identified best practices for obtaining or deriving airport-related ground access vehicle (GAV) data for input into the following computer models or electronic databases: • Motor Vehicle Emission Simulator (MOVES), from EPA; • Emissions Factor Model (EMFAC), from the California Air Resources Board (CARB); • Aviation Environmental Design Tool (AEDT), from FAA; • AERMOD, from EPA; and • CAL3QHC and CAL3QHCR line source models, also from EPA. 1.1 Purpose of the Guidebook The objectives of this guidebook are to provide analysts (e.g., air quality, traffic, planning) with methods to obtain or derive GAV-specific data for input into the listed models. More spe- cifically, the two principal objectives of this guidebook are: 1. To provide clarity and consistency about methods for quantifying airport GAV activity for the purposes of emissions modeling, and 2. To provide guidance that airports can use to collect and/or develop these data in ways that are accurate, cost-effective, and appropriate for the application. Supporting objectives also important to obtaining or deriving GAV data include defining the types of airport GAV, identifying sources and methods for obtaining GAV data, determin- ing the suitability of data, delineating boundaries for computing GAV emissions, and describing airport GAV infrastructure. To perform emissions modeling, analysts need an understanding of the various types of GAV, factors that affect the emissions that result from operation of the vehicles, and the airport-related infrastructure on which GAV operate. These topics also are addressed in the guidebook. The guidebook also presents a systematic, three-tiered approach analysts can follow when making decisions about the data needed for the analysis and for collaborating with others on data collection. Such a methodical, collaborative approach can yield a more cost-effective data collection/data development effort based on the specific needs and circumstances of each air quality assessment. Lastly, a tutorial has been prepared to aid the analyst through this guidebook and its application. Two primary purposes for obtaining input data and computing GAV-related emissions are (1) airport planning (e.g., to assess the effects of airport improvements on emissions) and (2) support of required National Environmental Policy Act (NEPA) documents that involve the C H A P T E R 1

Introduction and Background 3 quantification or disclosure of GAV emissions. GAV emissions also may be computed for inclu- sion in State Implementation Plans (SIPs). If air emissions modeling must be performed for a proposed airport project/action under NEPA, the air quality assessment will be one component of a much larger set of analyses that probably address surface transportation/traffic planning, airport noise, and a number of other environmental impact categories and issues. The air quality analyst is seldom the entity responsible for the actual collection of the GAV data that are needed for emissions modeling. Most often, data collection is part of the scope of work for ground transportation analysts or traffic engineers. These transportation consultants collect the data primarily for use in traffic studies that support the design of, or change to, an airport’s ground transportation system (i.e., access and circulation roads, curbsides, parking facilities, etc.). Because the air quality analyst often derives the GAV data used in the emissions modeling from the transportation consultants’ work, it is helpful if the air quality analyst has early input to the development of the transportation consultants’ approach and end-points for data collection (i.e., the transportation consultant’s scope of work). This input helps ensure that the resulting data also are useful for emissions modeling. 1.2 Contents of the Guidebook The guidebook is organized in five chapters that build the content progressively. For guide- book users who wish to focus on particular topics of interest, the Quick Lookup Guide (see text box) provides an index to the most commonly cited subject matter. • Chapter 2: Computer Models describes the types and functions of computer models com- monly used for computing airport GAV emissions, including MOVES, EMFAC, and AEDT; • Chapter 3: Airport GAV Fleet and Operational Characteristics identifies the various types of airport-related GAV and their operating characteristics, with the emphasis on applying these data and information to the computer models discussed in Chapter 2; Topic Chapter • Data collection methods 6 • Fuel types 3 • Future conditions 6 • GAV data requirements 5 • GAV types 3 • Idle times 6 • Infrastructure 4 • Models 2 • Operating speeds 6 • Purposes of modeling 5 • Regional traffic 5 • Speeds 3 • Temporal factors 5 • Tiered approaches 5 • Traffic volumes 6 • Vehicle mix 6 Quick Lookup Guide

4 Guidebook for Quantifying Airport Ground Access Vehicle Activity for Emissions Modeling • Chapter 4: Airport GAV Infrastructure provides information pertaining to airport facilities on which GAV commonly operate and the types of GAV that occur in these areas; • Chapter 5: Emissions Model Data Requirements contains information pertaining to the data requirements for conducting GAV emissions modeling according to three different approaches (i.e., Tiers I, II, and III); and • Chapter 6: Data Collection and Development discusses the various and appropriate data collection and development methods for computing GAV emissions under both existing and future conditions. A glossary, references, list of abbreviations, and frequently asked questions and answers are provided in the back matter of the guidebook. For brevity and ease of use of the guidebook, the Contractor’s Final Report containing supporting information and data collected or developed during the course of the ACRP Project 02-63 research can be accessed from the project webpage at www.trb.org. Finally, an interactive PowerPoint tutorial is provided to aid in the application of the guidebook. The tutorial can be downloaded from a link on the guidebook webpage.