Simulation Options for Airport Planning (2019)

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14 Simulation tools can be used on a wide range of projects and for varying purposes. To focus the discussion for this report, information collected from the study survey is combined with relevant simulation studies found in recent industry publications to provide the reader a holistic view on simulation study project types for airport planning and design. This chapter also tries to provide an idea of the required resources, simulation model maintenance requirements, and general practices associated with specific simulation tools. The use of simulation tools to support airport planning and design studies is very popular among airport planners and consultants and is, in some cases, required by FAA to support major airport or airspace design projects. Although FAA does not mandate the use of specific tools, the overall use of simulation tools is a de facto requirement for any major planning effort. From an airport planning and design perspective, simulation and modeling tools can support several different areas and products. As Figure 3 shows, the use of simulation tools is very popular for airport, airspace, and ter- minal applications, but they are also sometimes used to analyze other transit applications. The survey results and literature review also show that the types of simulation tools used by industry seem to depend heavily on factors such as the airport operational environment and airport size. The survey also indicates that capacity/demand planning is likely the most popular area for use of simulation tools, with master planning projects also often using them. The most common perceived benefits of conducting simulation studies in support of airport planning and design include proofs-of-concept for decision support, the generation of data to support policy and financial analyses, design decision support, and long-term capacity planning. Figure 4 illustrates these benefits and their relative importance levels based on the survey results. Generally, analytical and simulation models can be categorized based on their area of appli- cability, level of fidelity, and analysis capabilities. As Figure 5 shows, more than 90 percent of survey respondents indicated that they use purpose-built commercial simulation tools for airport planning and design purposes. The same percentage of respondents also use these com- mercial tools for airspace studies. About 30 percent of those surveyed also noted that they sup- port these analyses using spreadsheet or other in-house models. This shows that higher fidelity tools are also frequently supported by generic applications, including spreadsheet tables and basic queueing models that use generic software tools such as Arena or Simio. Airspace By far the most common simulation project for airspace studies is the assessment of airspace restrictions on runway and airport capacity. This includes simulation-based evaluations of pro- posed airspace procedures as well as impacts of TFM decisions on airport ground operations. C H A P T E R 3 Industry Perspectives of Simulation Tools for Airport Planning and Design

Industry Perspectives of Simulation Tools for Airport Planning and Design 15 Figure 4. Survey results—simulation analysis benefits. Figure 3. Survey results—simulation use by area. Figure 5. Simulation tool types.

16 Simulation Options for Airport Planning Other popular projects for the use of airspace simulation tools are air traffic control (ATC) procedure design and evaluation and Traffic Management Advisor/Terminal Radar Approach Control (TMA/TRACON) capacity planning, as well as obstruction analyses. The most common airspace simulation projects and simulation tools that were noted by survey respondents and found in recent literature and project reports are listed in Table 1. Older and out-of-date simulation tools have generally been discounted for the purpose of this synthesis report unless they are narrowly focused and have few other alternatives. As an example, Figure 6 depicts a TRACON simulation in AirTOp with vectoring aircraft on point-merge arrival procedures to two parallel runways. Given some of the intricacies of ATC operations, the simulation tools required to model air- space operations are typically high-fidelity tools that require significant resources and hands-on knowledge. The inputs to airspace simulation models are often generated using more specialized tools that are used to develop Area Navigation/Required Navigation Performance (RNAV/RNP) procedures, airspace designs, and other air traffic flow models. For some of the common tools such as TAAM and AirTOp, there are direct input data conversion utilities available that can ease the interface burden. However, most of the time some manual data transformation and process- ing work is still required. Table 2 provides a basic idea of the types of input data and external model interfaces that are commonly observed for airspace simulation studies. Airport or Airfield For detailed airport planning and design studies, airport or airfield simulation tools are most commonly used to analyze airport, runway, and gate capacities and associated delays. This report focuses solely on aircraft operations on the airfield. Numerous simulation tools can also simulate ground vehicles and other airfield objects, but these have not been specifically highlighted. Presumably, since the fidelity of airfield simulation models and associated resource and data requirements can vary significantly from simple runway capacity spreadsheet models to more sophisticated custom discrete-event simulations of the entire airfield, the survey respondents generally indicated a slightly lower level of difficulty in conducting these types of simulation studies. However, higher fidelity simulation tools such as TAAM and AirTOp—both of which are capable of simulating airspace and an airport or airfield at the same time—still require significant knowledge and expertise. Application Software Tools Master planning Procedure design Future concepts TMA/TRACON impact planning Obstruction planning Macro-economic analyses ADSIM+ AirTOp Data Analysis Reporting Tool (DART) Future ATM Concepts Evaluation Tool (FACET) SIMMOD/SIMMOD Plus/Pro SkySafe Systemwide Analysis Capability (SWAC) systemwideModeler TAAM TARGETS Table 1. Software tools for airspace simulations.

Figure 6. AirTOp TRACON airspace simulation. Source: AirTopsoft.

18 Simulation Options for Airport Planning The types of studies most commonly associated with airport or airfield simulation tools are: • Master plans (runway, gate, and airfield capacity and delay planning). • Construction phasing and impact analyses. • Irregular operations planning. Airfield simulation tool fidelity can vary significantly depending on the phase of the study as well as the types of metrics that are needed to substantiate findings. For example, spreadsheet and high-level tools may be used during the initial or strategic planning phase, whereas high- fidelity tools are needed for master planning and comprehensive design assessments. Figure 7 shows a high-fidelity airfield simulation model of New York’s John F. Kennedy (JFK) Inter- national Airport that may be used for detailed master planning studies. There is quite a range of simulation tools that are currently used for airport and air- field simulation purposes, and the type of tool used depends heavily on the scope of the study. Table 3 lists the most commonly used airport or airfield simulation tools and their application areas. Desired metrics also vary depending on the level of simulation tool fidelity required: from basic capacity-level information for runways and gates, to maximum airport and runway capacities and delays, to hourly throughputs, delays, gate usage, and other ground movement statistics (TransSolutions et al., 2014). Airport and airfield simulation studies may also support environmental assessment and impact studies. Table 4 illustrates the types of input data as well as the simulation tool external interface outputs that are most common and relevant for airport planners. Figure 7. TAAM airfield simulation of JFK. Source: Cignus Consulting. Inputs External Model Interfaces Airspace procedure designs (i.e., RNAV/RNP) Airspace sectorization Airspace route structures Airspace flow constraints Letters of Agreement (LOAs) Airspace/airport demand Custom visualization tools Environmental models Cost–benefit models ATC tower simulators Table 2. Airspace simulation inputs and external model interfaces.

Industry Perspectives of Simulation Tools for Airport Planning and Design 19 Terminal Passenger Flow Terminal passenger flow simulation tools can be used to model almost all passenger processes within and near the terminal building, including: • Passenger enplanement and deplanement. • Ticketing areas (desks, kiosks, remote). • Security screening checkpoints. • Baggage claim and carousels. • Airport ground access and flows. • Curbside processes. These simulation tools follow a similar categorization as other tools with macroscopic, mesoscopic, and microscopic fidelity levels. A detailed discussion of the various types of passenger flow simulation concepts can be found in Modeling Emergency Evacuation of Indi- viduals with Disabilities (Manley et al., 2011). Regarding simulation study complexity, survey respondents generally considered passenger simulations to be less difficult to conduct than airspace and airport or airfield studies. The simulation analysts should be warned, however, that higher level, macroscopic analytical models of passenger flow within an airport terminal environment can be difficult to develop and Application Software Tools Master planning Capacity planning and design Construction and operations planning Resource planning Irregular operations planning Flight schedule evaluations ACRP Spreadsheet Capacity Model AirTOp ArcPort AviPlan Airside pro CAST Aircraft DART FAA/National Aeronautics and Space Administration (NASA) Annual Delay Model Future ATM [air traffic management] Concepts Evaluation Tool (FACET) MassMotion runwaySimulator SIMMOD SIMMOD Plus/Pro Systemwide Analysis Capability (SWAC) TAAM Table 3. Software tools for airport and airfield simulation and applications. Simulation Inputs External Model Interfaces Airfield design layouts Terminal design layouts Airport future flight schedules Construction phases and zones Airport ATC and ground operating procedures Custom visualization tools Environmental models Cost–benefit models Gate schedule analysis tools Table 4. Airport and airfield simulation inputs and external model interfaces.

20 Simulation Options for Airport Planning analyze for terminal infrastructure capacity concerns due to highly complex terminal structures and transient demand patterns (Solak et al., 2009). Any study in which detailed statistics such as “X percent of passengers have to wait more than X minutes” are desired generally requires microscopic simulation tools. However, frequently the results obtained from these simula- tion tools are more detailed and substantive than the underlying assumptions actually support (Landrum & Brown et al., 2010). Table 5 provides a list of passenger simulation tools and their application areas based on information gathered from the survey and recent literature. To demonstrate visualization capabilities, Figure 8 presents a screenshot of a CAST Terminal passenger simulation model that integrates check-in and security checkpoint processes. As ACRP Report 25: Airport Passenger Terminal Planning and Design: Volume 1, Guidebook stated: Computer simulations are often a useful tool in checking that each terminal passenger and baggage processing function is in appropriate balance with one another, thereby ensuring that no single function becomes a bottleneck that adversely affects the overall LOS (Landrum & Brown et al., 2010). To support these types of analyses, metrics for passenger flow simulations can include arrival and departure patterns and trends, system capacities, resource availability, and security staffing requirements (Fayez et al., 2008). They may also focus on irregular operations that assess such Application Software Tools Terminal passenger capacity planning Passenger/terminal process design Check-in and security checkpoint design Staff/resource planning Emergency management and risk management Security threat analyses ACRP models AirTOp ArcPort CAST Terminal MassMotion Table 5. Software tools for terminal passenger simulation. Figure 8. Comprehensive airport simulation technology (CAST) terminal passenger simulation. Source: Airport Research Center.

Industry Perspectives of Simulation Tools for Airport Planning and Design 21 things as operational impacts of equipment failures, emergency evacuation and risk manage- ment strategies, and passenger flow system variability and randomness. Table 6 provides an overview of relevant passenger flow simulation tool inputs and outputs. Higher fidelity passenger flow simulation tools will accurately model passenger movements within a terminal structure using stochastic representations of historic passenger trends and relevant process times. Some tools may even use grids rather than directed passenger movement routes—or some dispersion of passenger movement along the route—to more accurately represent actual human behavior. Terminal Systems The modeling of terminal systems such as baggage systems and bus and train links generally follows a more generic queueing theory approach. Although some simulation tools may provide integrated passenger-process simulation capabilities, most studies typically depend on more generic medium-fidelity simulation software. These types of tools simulate objects—baggage, buses, trains, and others—as they traverse through networks with capacitated resources. Most common simulation tools used to model generic processes—such as Arena, Vissim, and Simio—have both simple process-level visualiza- tion capabilities as well as 3-D representations of the same process. Table 7 lists the predominant software tools and applications. As a visual example, Figure 9 shows a rail-link and bus terminal simulation using Simio. Using metrics such as system and process delays and resource usage, these simulation tools can be used to assess process designs or, more tactically, to develop staffing and resource plans for day-to-day operations. Simulation Inputs External Model Interfaces Terminal design layouts Resource requirements (i.e., number of security checkpoints) Passenger demand Boarding area designs and processes Check-in locations and strategies (i.e., kiosks) Emergency operational processes Custom visualization tools Environmental models Threat analyses Resource and staffing models Table 6. Terminal passenger simulation inputs and external model interfaces. Application Software Tools Baggage system planning Bus/train/shuttle planning Arena Simio Vissim Table 7. Software tools for terminal system simulation.

22 Simulation Options for Airport Planning Ground-Access Simulation Curbside operations are an integral part of the terminal operation as they are the interface between two transportation systems—airports and roadways. Like airside operations, ground access and curbside studies can focus on the evaluation of capital improvements such as road- way widening and construction of multiple curbside levels or on operational changes that aim to maximize vehicle throughputs or minimize delays. ACRP Report 40: Airport Curbside and Terminal Area Roadway Operations also provided a comprehensive summary of ground access and terminal area roadway analysis (LeighFisher et al., 2010). It was not until ACRP Report 40 that guidelines that focused on the analysis of airport curbsides were defined. This report introduced a simulation tool called Quick Analysis Tool for Airport Roadways (QATAR), which was a simple macroscopic queuing model for curbside congestion and airport roadway analysis (Harris, Nourinejad, and Roorda, 2017). The types of projects that curbside vehicle simulation tools generally support include: • Airport road access planning. • Airport terminal access planning. • Work zone impact analyses. • Consolidated transportation facility analyses. Table 8 lists the predominant simulation tools and study areas based on survey results and searches of recent literature. More microscopic curbside simulation tools are also available that focus on the simulation of individual vehicles on airport roadways. Although they can simulate curbside operations at a high level of detail, they are generally built on other urban transportation system simulation tools and require more detailed input data (Duncan and Johnson, 2000). These tools may not capture some of the intricacies of airport roadway systems, but their detailed vehicle simula- tion and visualization capabilities may be useful in graphically modeling curbside operations, which may still be useful in demonstrating and analyzing bottlenecks and vehicle ingress and egress issues (LeighFisher et al., 2010). Figure 9. Simio rail-link and bus terminal simulation.

Industry Perspectives of Simulation Tools for Airport Planning and Design 23 Simulation Results and Application The output data generated by simulation tools can vary significantly, as can the post- processing and result visualization capabilities. Many tools include custom analysis and reporting functionality that can present commonly used summary statistics, tables, and graphs. However, most experienced simulation users favor the exportation of raw output data to custom analysis tools that were purposely developed to obtain relevant results quickly and efficiently for incorporation into reports and presentations. Simulation outputs can also, in many cases, be used to feed and support ancillary—or secondary—tools for further study. In addition to custom analysis packages, the types of secondary models that survey respondents noted most frequently include: • Custom visualization and presentation tools. • Environmental, noise, and emissions software. • CBA or financial analysis tools. • Others such as ramp and gate analysis charts and vehicle circulation models. However, it should be noted that very rarely are simulation output data directly usable in secondary tools. Most of the time, data transformations and tweaks are necessary to ensure meaningful secondary tool results. Multiruns The survey also indicated that a clear majority of simulation analysts favor using multiruns for their airport and airspace simulation studies. Many passenger and generic process tools already natively use this Monte Carlo Simulation concept, and it is available as a function within most major airspace and airfield simulation tool packages. Multiruns allow airport and airspace modelers the ability to insert stochastic variability into the otherwise deterministic simulation software. Simulation scenarios are run numerous times with added randomness in factors such as: • Aircraft, passenger, and vehicle departure and arrival times. • Vehicle performance. • Process times. Essentially, the use of multiruns gives analysts the ability to conduct basic sensitivity analyses to assess how the modeled system behaves when environmental variables change. This adds more realism to the simulated scenarios and also provides validation of model robustness by ensuring that models can be run within a realistic range of environmental variables without gridlocking. Application Software Tools Airport road access planning Airport terminal access planning Evaluation of construction zone impacts Toll plaza analysis Pedestrian flow analysis Transit facility planning ACRP tools QATAR Synchro University of Missouri-St. Louis Queue Theory Model Vissim Vistro Table 8. Software tools for curbside and ground access simulation.

24 Simulation Options for Airport Planning Simulation Model Maintenance One aspect of applying simulation tools across the board that should not be discounted is that after a study has concluded, simulation models usually need to be maintained for future reuse. As such, they may require regular maintenance and input data updates in terms of: • Airport, airspace, and passenger demand schedules. • Gate and apron usage and selection strategies. • Airport and terminal layouts. • Terminal system processes, including locations of concessions and other subsystems that affect passenger flows. • ATC procedures, taxi patterns, and other operational procedures. Airport planners and designers considering the use of simulation tools should be aware that the maintenance of simulation models and the continual update and revalidation can require significant effort. This is particularly true with high-fidelity models.