Papers
Capturing the Impact of Fuel Price on Jet Aircraft Operating Costs with Engineering and Econometric Models
Co-authored with Mark Hansen
Challenges in forecasting fleet development and deployment are in part due to fuel price uncertainty. To address this issue, a recent study developed an aircraft-specific Leontief technology operating cost model (LM) to compare aircraft costs under fuel price uncertainty. This model considers individual aircraft types to be Leontief technologies, such that the key drivers of cost must be used in fixed quantities. While asserted in the literature that models in this form can more accurately predict operating costs, the Leontief specification precludes a precise examination of how aircraft size will change due to economic forces. To this end, an econometric operating cost model (EM) is developed. The translog functional form is used to capture the effect of the key drivers of cost on jet operating costs and also allow for substitution between inputs. A comparison of the LM and EM shows that the Leontief technology assumption limits the LM to capturing operating costs in only a snapshot in time, while the EM captures the input substitution that occurs with factor price changes. The conclusion that the EM has strong predictive potential encourages a strengthening of the model towards capturing costs related to passenger preferences. This study takes a total logistics cost approach (TLC) and considers passenger value of frequency along with operating cost to be the total cost per operation. The cost-minimizing seat size is smaller and more reflective of existing conditions under TLC compared with operating cost alone, yet the difference diminishes as fuel price increases. This study highlights the predictive potential of econometric cost models and also the importance of considering passenger preferences in predicting future aircraft economics.
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Assessing the Role of Operating, Passenger, and Infrastructure Costs in Fleet Planning under Fuel Price Uncertainty
Co-authored with Mark Hansen
Aviation system planning is challenged by the rapid increase in fuel prices and uncertainty in air traffic management (ATM) charges. As airlines decrease capacity and decommission older aircraft and aviation navigation service providers ponder new ATM charging schemes, a critical question is: which aircraft provide air transportation service for the lowest cost? This study evaluates the introduction of a minimally utilized aircraft type in the United States, the 72-seat turboprop, compared with currently operated narrow body and regional jet aircraft. Homogeneous fleets of these vehicles are compared for operating, passenger preference, and ATM costs over a range of fuel prices and the minimum cost fleet mix is determined. Findings include that the regional jet exhibits a higher cost per passenger than the turboprop for the entire fuel price and stage length space when operating costs are considered alone. When passenger costs are considered in addition to operating costs, there exists an equal cost per passenger curve between these two aircraft for fuel prices below $4.00/gallon. When infrastructure costs are considered, the fuel price and stage length space where the turboprop offers a lower cost increases. The comparison of the turboprop with the narrow body shows that an equal cost curve exists under all cost combinations considered. With the introduction of ATM charging, the flat landing fee favors the narrow body, while variable ATM charges increase the space where the turboprop offers the lower cost. This analysis shows that aircraft fleet selection is highly sensitive to fuel prices, passenger costs, and ATM charging schemes.
Politics, Public Opinion, and Project Design in California Road Pricing
Co-authored with A. Evans, M. Gougherty, E. Morris; published in Transportation Research Record, 2007
Growing numbers of decision makers are becoming more open to charging users of roads to fund transportation improvements, including transit alternatives. Despite significant progress, planners and policy makers still face many obstacles when considering road-pricing projects. This suggests that many of the factors that determine the success or failure of such proposed projects are not well understood and that proposed projects may include one or more aspects that prove to be deal breakers for key supporters. Four geographically diverse California road-pricing projects were selected for detailed case studies. Two projects that succeeded to implementation allow for an analysis of the critical political maneuvers made throughout the life of these priced facilities. One project that was ultimately halted in the later stages of planning and one planned but not yet implemented project are useful in evaluating what went wrong and what lessons can be drawn from these attempts to implement road pricing. The findings suggest that there are numerous ways to adjust pricing projects to gain public and political support. Generally, projects should try to provide more capacity, travel-time savings, and travel options, and avoid pricing facilities that have no free alternatives. Nevertheless, the manner in which projects are designated and revenues are used is highly context-specific, and some concessions in one area can improve acceptability in another. The future of road pricing is uncertain, and pricing projects should be considered only on a case-by-case basis, depending on local attitudes, the use of the revenue generated, and the specific facility in question.
Modeling and Measuring Greenhouse Gas Reduction from Low Carbon Airport Access Modes
UCTC Working Paper
The warming of the Earth’s temperature due to human activities, known as anthropogenic climate change, is a threat to the environment and human health. The transportation sector is a major contributor to anthropogenic climate change, being responsible for 27 percent of all domestic greenhouse gas (GHG) emissions in 2003. Within this sector, urban surface travel has been the major focus of researchers and policymakers. To broaden this focus to include interregional travel, the proposed research focuses on the aviation sector. Airport access modes are shown to be a large proportion of aviation system GHG emissions; due to their share and political and engineering realities they are targeted for aviation system GHG reduction. Discrete choice models are used to study the entry of clean airport access modes into the market, and it is found that the entry of a subsidized electric vehicle door‐to‐door van could reduce GHG emissions by 36 percent.
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A Comparative Evaluation of Greenhouse Gas Emission Reduction Strategies for the Maritime Shipping and Aviation Sectors
Co-authored with Bo Zou and Mark Hansen
The transportation sector is one of the largest sectors contributing to Greenhouse Gas (GHG) emissions, the gases which cause anthropogenic climate change. The aviation and maritime shipping sectors are growing segments of transportation GHG emissions, yet mitigation strategies have largely avoided these sectors. There is a need for clearly defined strategies which can reduce GHG emissions of maritime and aviation operations and for an understanding of the potential magnitude and barriers to reduction. This research presents a framework for GHG emission reduction strategies and evaluates their reduction potential for maritime and aviation operations.
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Modeling the Logistics of FedEx International Express
Co-authored with A Boubert, V Calloud, and A Papson
The FedEx international express network ships 11.5 million pounds of packages per day through 15 international hub airports and local airports from which packages are locally collected and distributed. FedEx shipment data and estimation methods based on logistic theory provide for the development of a logistic cost function. To determine the lowest cost operating strategy for FedEx international express, logistic costs are estimated for the current network with and without transhipment points, which consolidate international shipments into fewer hub airports with higher volume. These estimation methods are then applied to a proposed network expansion and the related costs are estimated and compared. The potential to expand the network and increase overall revenue is explored, as the increase in costs is balanced by an increase in revenue. An alternate strategy is explored to reduce cost, including the introduction of a more diversified air fleet and the creation of a hybrid network with modified transshipment points. Through these alternate strategies, further cost savings for FedEx is realized through the use of larger aircraft and well as varying the number of transshipments due to demand between nodes. This study presents a method to estimate logistics costs and
presents a repeatable methodology to evaluate the impact of new technologies, larger distribution areas, and innovating shipping schemes on shipping revenues.
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Achieving a Higher Capacity National Airspace System: An Analysis of the Virtual Airspace Modeling and Simulation Project
Co-authored with Mark Hansen
The Virtual Airspace Modeling and Simulation (VAMS) project developed by the National Aeronautics and Space Administration (NASA) presents a detailed plan for increasing National Airspace System capacity. Interviews with aviation experts regarding the VAMS project led to lessons learned which can inform current modernization plans and processes, as the current system prepares for modernization. According to experts consulted, development should include a small number of project developers who provide periodic opportunities for wide stakeholder feedback; roadmaps should incorporate uncertainly and provide project guidance on a high level; and simulation tools are valuable to modernization efforts, yet assumptions should be documented and their sensitivity understood.
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