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Transportation Research Board (TRB) Papers

  • Forecasting Model for Air Taxi, Commercial Airline, and Automobile Demand in the United States (2008)

    A nationwide model predicts the annual county-to-county person roundtrips for air taxi, commercial airline, and automobile at 1-year intervals through 2030. The transportation systems analysis model (TSAM) uses the four-step transportation systems modeling process to calculate trip generation, trip distribution, and mode choice for each county origin–destination pair. Network assignment is formulated for commercial airline and air taxi demand. TSAM classifies trip rates by trip purpose, household income group, and type of metropolitan statistical area from which the round-trip started. A graphical user interface with geographic information systems capability is included in the model. Potential applications of the model are nationwide impact studies of transportation policies and technologies, such as those envisioned with the introduction of extensive air taxi service using very light jets, the next-generation air transportation system, and the introduction of new aerospace technologies.

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  • Logit Models to Forecast Nationwide Intercity Travel Demand in the United States (2007)

    Nested and mixed logit models were developed to study national-level intercity transportation in the United States. The models are used to estimate the market share of automobile and commercial air transportation between 3091 counties and 443 commercial service airports in the United States. Models were calibrated using the 1995 American Travel Survey and separate models were developed for business and non-business trip purposes. The explanatory variables
    used in the utility functions of the models are travel time, travel cost, and traveler’s household income. Given an input county-to-county trip demand table, the models were used to estimate county-to-county travel demand by automobile and commercial airline between all counties and commercial service airports in the United States. The model has been integrated into a computer software framework called the Transportation Systems Analysis Model (TSAM) that estimates nationwide intercity travel demand in the United States.

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  • A Model to Estimate Origin-Transfer-Destination Route Flows and Origin-Destination Segment Flows across the Continental United States (2007)

    This paper introduces an Origin-Transfer-Destination (O-T-D) model that predicts the route and segment passenger flows between airport pairs using origin-destination (O-D) passenger demand between airport pairs. The model is developed based on a multinomial logit model and covers 443 nodes (i.e., airports) and about 6000 links (flight segments). To create airline schedules between any airport pair, a network-building module has been developed using the Official Airline Guide (OAG) that provides flight segment information. Flight fares for routes are extracted from Airline Origin and Destination Survey (DB1B). The observed segment passenger flows between airport pairs are also obtained from DB1B. Two different types of logit models are calibrated and then validated by comparing estimated route and segment passengers between airport pairs with the observed route and segment passengers obtained from the DB1B and the Form 41 Segment Data (T-100), respectively.

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  • Development of an Airport Choice Model for General Aviation Operations (2006)

    The General Aviation Airport Choice model developed estimates General Aviation (GA) person-trips and number of aircraft operations given trip demand in the form of GA person trips from counties. A pseudo-gravity model is embedded in the model to distribute the inter-county person-trips to a prescribed set of airports in the US. The airport-to-airport person-trips are split into person-trips by three aircraft modes (single, multi and jet engine) using an attractiveness factor based on average occupancy, utilization and a distance distribution factor for each aircraft type and the number of aircraft based at each airport. The person-trips by aircraft type are then converted to aircraft operations using occupancy factors for each aircraft type.
    The final output from the model are aircraft operations trip-tables by aircraft type between the airports in the model. The GA trips are estimated in order to provide a means of assessing the impact of GA activities on the National Airspace System. The model output may be used to assess the viability of GA aircraft serving as a competitive mode of transportation for intercity travel.

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  • Preliminary Assessment of Lower Landing Minima Capabilities in the Small Aircraft Transportation System Program (2005)

    A preliminary assessment is presented of the required lower landing minima (LLM) capabilities needed to support the Small Aircraft Transportation System (SATS) Program. The goal of this analysis is to understand the number of potentially challenged SATS airports and to identify methods to remove obstacles by using technology solutions. Four obstacle removal methods are considered to assess the challenges faced by the SATS Program in providing LLM capabilities to 3,416 U.S. airports. Two views of runway obstacle analysis are presented: a critical object analysis and a detailed multiobject analysis that includes terrain information. A comparison is made between decision altitudes (DAs) derived by approach lighting infrastructure and glide path angle thresholds and DA values considering other airport characteristics such as terrain. A detailed case study is presented to compare the single critical object analysis with the more detailed multiobject analysis, which was performed for Blacksburg Airport, in Virginia.

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  • Measuring Benefits of Controller-Pilot Data-Link Communication (CPDLC) System in an Airport Area Using a Microscopic Simulation Model (2005)

    The Federal Aviation Administration (FAA) plans to implement a controller-pilot data-link communication (CPDLC) system in the near future. Unlike conventional voice-channel communication systems, the CPDLC system allows pilot and controllers to exchange messages via specially designated data links thus reducing voice communication congestion. Under the proposed CPDLC system, pilots can see an air traffic controller message in text format on a Multifunction Display (MFD). Similarly, pilots can send a message to controllers using pre-coded messages via the MFD. By reducing communication times, the CPDLC system is expected to reduce flight delays at congested airports and in the airspace. The system is also expected to decrease operational and communication errors that could lead to fatalities. The CPDLC system can be implemented in multiple domains in the air traffic control system including airport area, Terminal Radar Approach Control (TRACON) areas, Air Route Traffic Control Centers (ARTCC). Previous studies have focused on the evaluation of CPDLC benefits in either the TRACON or ARTCC domains. In this paper, we assess the benefit of implementing CPDLC system in an airport area using a microscopic airport simulation model.

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  • A Model to Assess the Mobility of the National Airspace System (NAS) (2004)

    One of the ways to define mobility in a transportation system is total travel time for all travelers using the transportation network. A good assessment of the mobility is essential for knowing the points of congestion in the network and the factors responsible for the congestion. Also the change in mobility from the baseline to the horizon year would give the modeler an idea of the effectiveness of the various transportation systems. One of the applications of the mobility measurement is the evaluation of aviation technologies proposed by FAA to ease the congestion. This paper addresses a method to estimate the mobility of the air transportation network in the baseline year (2000). Also presented is a method to estimate the mobility to the horizon year by considering congestion on the roadway.

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  • An Integrated Model To Study The Small Aircraft Transportation System (SATS) (2003)

    A systems engineering methodology was used to study the National Aeronautics and Space Administration's (NASA's) Small Aircraft Transportation System (SATS) concept as a feasible mode of transportation. The proposed approach employs a multistep intercity transportation planning process executed inside a Systems Dynamics model. Doing so permits a better understanding of SATS impacts to society over time. The approach is viewed as an extension to traditional intercity transport models through the introduction of explicit demand-supply causal links of the proposed SATS over the complete life cycle of the program. The modeling framework discussed is currently being used by the Virginia SATS Alliance to quantify possible impacts of the SATS program for NASA's Langley Research Center. There is discussion of some of the modeling efforts carried out so far and of some of the transportation modeling challenges facing the SATS program ahead.

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  • Modeling the Economic Impacts of Adverse Weather into Enroute Flights (2002)

    A methodology is presented to quantify and minimize the effect of adverse weather on commercial and general aviation traffic. The method described uses two simple models, the Air Traffic Flow Model and the Adverse Weather Impact Model, to quantify the impact of adverse weather into regional airspace operations in the National Airspace System (NAS). The impact of adverse weather in aviation in system delays is well documented. Weather is a major source of delays in NAS. In the past 5 years, weather has accounted for 71.2% of all delays in NAS according to statistics compiled and published by the Federal Aviation Administration. Adverse weather varies in extent from a few square miles to thousands of square miles. Besides causing delays, it affects the safety, comfort, and efficiency of aviation. Better models to manage air traffic under adverse weather conditions are needed. Ultimately, these models could be deployed as decision-support systems to aid air traffic personnel to divert traffic optimally in a real-time scenario.

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  • A Time-Dependent Network Assignment Strategy for Taxiway Routing at Airports (2002)

    A time-dependent network assignment strategy is proposed for efficiently handling aircraft taxiway operations at airports. The suggested strategy is based on the incremental assignment technique that is frequently adopted in many urban transportation studies. The method assumes that the current aircraft route is influenced by previous recent aircraft assignments in the network. This simplified assumption obviates the need for iterative rerouting procedures for attaining some pure equilibrium state, which in any case might not be achievable in practical airport taxiway operations. The main benefit of applying the time-dependent network assignment approach to taxiway operations is the reduction and avoidance of possible conflicts that produce delays. Also proposed is a prototype of a fully time-dependent network assignment scheme that dispatches aircraft based also on future anticipated assignment. The suggested methodology could be adopted in the deployment of automated taxiway guidance systems that are planned for future implementation at congested airports.

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  • Modeling Airside Airport Operations Using General-Purpose, Activity-Based, Discrete-Event Simulation Tools (2001)

    The application of activity-based simulation techniques to model runway operations at airports is described. The simulation tool used, STROBOSCOPE, is a discrete-event simulation system and programming language based on the three-phase activity scanning simulation paradigm. The model developed can be used as a tool to estimate runway capacity, delays, and double runway occupancy instances.

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  • Airport Automated People Mover Systems: Analysis with a Hybrid Computer Simulation Model (2000)

    Automated people movers (APMs) have become an attractive solution to mobility problems associated with large airport terminals. A hybrid computer simulation model (called APMSIM) that has been developed to simplify the operational analysis of airport APM systems is presented. Given an airport passenger demand function, along with various APM vehicle technology and airport terminal characteristics, the model estimates time-varying level-of-service characteristics of the terminal including queues and processing times. The model simulates the movement of individual passengers and APM vehicles in the system network. APMSIM constitutes a design tool for airport planners and designers for determination of the sensitivity of system performance for a range of APM design parameters, examination of the flexibility of an APM system under given operational policy and network configurations, and estimation of APM vehicle energy consumption on the basis of network constraints and system characteristics. The model is a hybrid discrete-event and continuous simulation model developed in EXTEND, a general-purpose simulation software.

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  • Systems Engineering Framework To Assess the Impacts of Very Large Capacity Aircraft in Airport Operations and Planning (1999)

    A methodology is presented to investigate the effect of Very Large Capacity Aircraft (VLCA) operations at existing and future airports. The procedure that is described investigates airport and airline impacts of VLCA operations using a systems engineering approach to understand the tradeoffs between economic and technological operational factors. Specific topics discussed in this analysis are (a) the effect of VLCA on airport capacity, (b) development of new geometric design guidelines, (c) landside impacts and gate compatibility issues, (d) airside capacity impacts, and (e) possible noise and pavement design impacts. These aspects are modeled using the Systems Dynamics methodology, which permits a blend of technological and socioeconomic variables into the same model. Realistic parametric templates of feasible aircraft designs are defined using computer methods, and the impacts of proposed designs in airport operations, capacity, and economics are explored. The analysis focuses on the airside and landside capacity, geometric design constraints, and pavement and acoustic impacts of VLCA operations. A systems engineering perspective is used when aircraft design inputs have quantifiable outcomes on airport capacity, on infrastructure changes, and ultimately, on the cost of operations. Cost-effective ways to facilitate the operations of VLCA at existing and future airports are identified, including new design guidelines.

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  • Limited Study of Flight Simulation Evaluation of High-Speed Runway Exits (1999)

    The provision of high-speed runway exits is one of several alternatives to increase airport runway capacity through reductions in runway occupancy time. The Runway Exit Design Interactive model developed at Virginia Tech proposes new geometric design standards for high-speed turnoffs and an algorithm to locate optimal runway exits. The results from a limited flight simulation study that was conducted to assess the operational suitability of high-speed runway exits developed at Virginia Tech are presented. The flight simulation experiments were conducted at the Mike Monroney Aeronautical Center in Oklahoma City in a Boeing 727-200, 6-degree-of-freedom, full-motion-base aircraft simulator. The study used six FAA pilots rated in the Boeing 727-200 aircraft to obtain information about the operational suitability of the proposed high-speed exits. Pilot responses were extracted from questionnaires that were administered during the flight-simulation experiments. Aircraft state variable time histories extracted from the flight simulator computer were analyzed to verify the dynamic behavior of the aircraft as high-speed runway exits were negotiated. Two statistical experiments were carried out to evaluate the acceptance of the high-speed exit designs: (a) a two-factor analysis of variance test to verify differences in runway exit speeds and (b) nonparametric tests of pilots questionnaire responses. The results suggest that a new generation of high-speed runway exit geometries could be used to increase runway exit speeds without compromising safety or inducing extra workload on pilots.

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  • Computer Simulation Model for Airplane Landing-Performance Prediction (1996)

    A simple computer simulation model that predicts airplane landing performance on runways to locate high-speed exits is presented. A Monte Carlo simulation algorithm and empirical heuristics derived from field observations were used to estimate landing-roll trajectories that can be programmed quickly in a personal computer. The modeling process demonstrates statistically the validity of treating landing-roll profiles of various airplane models individually to locate high-speed exits. The model developed can be applied to a variety of airports and airplane types and is offered as an alternative to conventional methods for locating high-speed exits as well as a complement to more rigorous optimization methods.

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  • Characterization of Gate Location on Aircraft Runway Landing Roll Prediction and Airport Ground Networks Navigation (1995)

    This study presents an aircraft landing simulation and prediction model. The model uses simple aircraft kinematics coupled with individual parameters to describe the landing process. A multiobjective optimization and a shortest path algorithm are used to predict the aircraft exit choice and taxiway path in the runway taxiway network. By recognizing pilot motivation during the landing process, several influence factors such as terminal location, runway, and weather conditions are considered in the aircraft landing simulation. Random variables such as aircraft runway crossing height, flight path angle, approach speed, deceleration rate, and runway exit speed are generated to represent the stochastic landing behavior of aircraft by using a Monte Carlo sampling technique. With real-time input data, the model could provide information on aircraft exit choice, runway occupancy times, and shortest taxiway path to an assigned terminal location for both the pilot and the air traffic controller in a ground traffic automatic control system. This model can also be used to solve runway exit location problems by providing the expected distribution of aircraft landing distances and predict aircraft runway occupancy times. An interactive computer program has been developed on an IBM RISC 6000 workstation to perform these tasks.

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Air Transportation Systems Laboratory at Virginia Tech
301-P Patton Hall, Blacksburg, VA 24061
Phone: 540-231-4418 - Fax: 540-231-7532 - eMail: vuela@vt.edu