Airport System Planning
3. Scenario C. Stansted would be limited to 20 mppa and other southeast airports would not be able to take significant additional traffic
4.7 AIRPORT SYSTEM PLAN ANALYSIS
Several analyses may be conducted as part of the entire effort to develop the airport system plan. These are discussed in this section.
Determine Individual Airport’s Share of the System
Total demand at an airport is constituted of origin and destination (OD) traffic plus the number of transit and transfer passengers. The former can be modeled by airport choice models, while the latter is predicted by route choice models. These rather advanced forms of demand models are covered in Chapter 2.
Total airport
system demand Scenario for airport’s role in airport system
Route choice models Assume service levels in terms of:
Frequency Capacity
Equipment type
Fares
Airport choice model
Origin and destination passengers
Transfer and transit passengers
Total demand at airport
Are assumed No service levels in balance with
demand?
Accept:
Origins Destinations Transfers Transits
Yes
Figure 4.12 Flow chart of analysis for airport systems planning.
The process used to determine an individual airport’s share of the airport sys-tem total is depicted in Figure 4.12. The process indicates the steps for predicting an individual airport’s share of total system traffic when scenario analysis is used:
• A scenario for the development of the airport is set out in conjunction with scenarios for all other airports in the system.
• Airline service is postulated in terms of frequencies, capacity, equipment type (jet or turboprop), and fare levels.
• Originating and destined passengers are predicted using airport choice models.
• Transfer and transit passengers are predicted using route choice models.
• The total demand at the airport is compared with the airline supply levels assumed. When these are in balance, the demand obtained is accepted.
Develop the Comprehensive Airport System Plan
Where a comprehensive airport system plan is to be carried out, the required commit-ment of resources is likely to be extensive, especially in countries with well-developed air transport networks. The FAA has issued guidelines for preparing the airport sys-tem plan, including the metropolitan, regional, and state aviation plans (15). Federal law defines “integrated airport system planning” as “developing for planning purposes, information, and guidance to decide the extent, kind, location, and timing of airport development needed in a specific area to establish a viable, balanced, and integrated system of public-use airports.” This includes four main elements: (a) system needs identification; (b) systemwide development cost estimate; (c) studies, surveys, and other planning actions to decide which aeronautical needs should be met by a sys-tem of airports; and (d) standards prescribed by a state, except standards for safety of approaches, for airport development at nonprimary public-use airports. Therefore, the primary purpose of airport system planning is to study the performance and interaction of an entire aviation system to understand the interrelationship of the member airports.
The system evaluated in the plan can be the airports of a metropolitan area, a region (Figure 4.13), a state (Figure 4.14), or several bordering states.
Figure 4.13 Sample of a regional airport system (15).
Figure 4.14 Sample of a state airport system plan (15).
The airport system plan augments the NPIAS, which the FAA prepared in 1984 and periodically updates (16) to replace the earlier National Airport System Plan. The NPIAS integrates local airport master plans with state aviation system plans, as shown in Figure 4.15. The whole plan is updated by a continuous planning process (shown in Figure 4.16), whereby interim and formal plan updates are prepared as reappraisal determines them to be necessary.
While the NPIAS provides an overall structure which forecasts reasonably well overall demand and indicates the way in which this demand can be accommodated, it does not, however, provide for the dynamic forces industry experts on the system.
To assess industry dynamics, De Neufville and Barber (4) provided a methodological approach incorporating dramatic upheavals of the industry, such as deregulation and industry consolidation. The major reason is that the basic structure and building blocks of the NPIAS are essentially local airport plans. Nonetheless, the NPIAS format has performed reasonably well over the years in the U.S. context of a well-developed air transport mode. It should not, however, be used as a model for countries or states where the mode is not well developed; the bottom-up approach could in such cases lead to ill-constructed airport system plans. Even in the United States, which has a highly developed network, in the late 1980s considerable pressure was exerted to move from the traditional FAA method of airport systems planning to a more strongly centralized approach (17).
Area issues
Metro/regional plans
System users: military,
FAA, planners, other Local airport master plans
State aviation system plan
State aviation programs State, local land-use plans
NPIAS
Figure 4.15 Planning relationships for state aviation plan (15).
Figure 4.16 Continuous airport system planning process (15).
After several years of investigation into the problems involved, the Committee for the Study of Long Term Airport Capacity Needs recommended the following actions by the U.S. government to urgently improve the U.S. airport system (18):
• Setting up of a long-term strategic planning process with the FAA
• Immediate physical improvements to airport and aviation facilities to support a strategic planning process
• Definition of a set of short- and long-term goals for aviation
• Inauguration of a broad and greatly expanded research and development program in designated aviation areas
In coming to these conclusions, the committee looked at the future U.S. airport system by examining eight options for accommodating air travel demand (18):
• Make incremental capacity improvements at existing airports.
• Create new hubs at presently underused airports.
• Add new airports in metropolitan areas with high-traffic volume.
• Develop new airports dedicated to be transfer points (wayports).
• Apply administrative and regulatory techniques.
• Employ economic measures to redistribute demand and resources.
• Promote development of new aviation technology.
• Develop high-speed surface transportation technology.
These options were set within nine base scenarios of differing technological devel-opment and socioeconomic conditions. Finally, the committee examined and evaluated the following strategies of system development (18):
Strategy A: Continue on present course.
Strategy B: Build more airports in high-volume metropolitan areas.
Strategy C: Centralize system management.
Strategy D: Build an expanded, centrally managed system, using new airports in metropolitan areas with high volume.
Strategy E: Adopt a market approach with new airports, using economic measures to manage and allocate existing and new capacity.
Strategy F: Reconfigure the airport system, using new airports to serve as transfer points.
Strategy G: Revolutionize intercity transportation by introduction of new air and surface technology.
The strategies which offered the most promise for the satisfaction of future demand levels were found to be D, E, and G. If eventually adopted, these recommendations will have prompted a significant move of U.S. aviation planning in the direction of a strongly centralized or “top-down” philosophy.
Figure 4.17 depicts the top-down planning approach used for smaller secondary airport systems where much development is still likely to take place (4). This approach has a number of identifiable steps:
• The extent of the system to be considered should be identified.
• Existing airports and potential sites should be inventoried. This can be done at a more superficial level than required for the master planning of individual facilities (see Chapter 5).
• Develop scenarios for the roles to be played by different airports.
• Estimate total system demand under different demand growth scenarios (e.g., high, most likely, low).
• Develop scenarios for the various airports in a number of future systems. Syn-thesize the very numerous combinations into a small, robust set of options which best covers the range of options.
• Examine each scenario based on the following:
• Estimate air service levels in terms of capacity, frequency, and cost.
• Distribute systemwide demand using airport choice and route choice models (see Sections 2.10 and 2.17, respectively).
• Ensure that demand and supply, in terms of service levels, are in reasonable balance.
• Determine financial, economic, and environmental feasibility.
Figure 4.17 “Top-down” comprehensive airport systems planning analysis for secondary airport systems (4).
• Select the most robust scenario.
• Draw up a staged development plan.
• Establish a long-term capital budget program.
Airport System Performance
With the passage in the United States of the Inter-modal Surface Transportation Effi-ciency Act (ISTEA) of 1991 and the Transportation Equity Act for the 21st Century
(TEA-21) in 1999, the transportation planning community grew more cognizant of decision making of future investments in the transportation system from a multimodal perspective. In other words, there is competition between the modes that will be based on how each modal system fared and performed. Investment decisions on a rational multimodal basis will therefore have to be assessed based on the performance of each mode in a consistent way so that resource allocation across modes would maximize the contribution to the overall performance of the entire transportation system. The California Department of Transportation initiated an effort to identify and assess sys-tem performance measures of the state transportation plan that was conducted by the University of California at Berkeley under FAA funding through NEXTOR (19).
The state transportation plan proposed the system performance objectives to include three categories: economic vitality, safety and security, and mobility with system effi-ciency and cost-effectiveness. It also identified a set of desirable outcomes of two categories: effectiveness and efficiency and responsibility. In its analysis, the study proposed a performance measuring system that includes two main categories:
• Effectiveness and efficiency , focusing on mobility and accessibility, reliability, cost-effectiveness, customer satisfaction, and economic well-being
• Responsibility , covering sustainability, environmental quality, safety and secu-rity, and equity
System performance outcomes and respective measures are indicated in Table 4.2.
In complying with the Government Performance and Results Act of 1993, the FAA started introducing conditions and performance of the airports in the NPIAS plan
Table 4.2 System Performance Outcomes and Respective Measures (19) Proposed performance measures
California transportation plan update System performance outcomes Candidate performance measures Effectiveness and efficiency
Mobility/accessibility Travel time Delay (lost time)
Access to desired locations Access to the transportation system Reliability Standard deviation of average trip time Cost-effectiveness Customer satisfaction index
Customer satisfaction User opinion survey
Economic well-being Share of transportation final demand in gross regional or state product
Responsibility
Sustainability Household transportation costs Environmental quality Conformity/compliance
Livability Safety and security Accidents rates
Crime rates
Equity Income group share of mobility benefits
addressing six outcomes: capacity, safety, aircraft noise, pavement condition, acces-sibility, and financial performance (20). For each of these outcomes the FAA either compiles the data or asks airports to provide the data on a regular basis.
Another study conducted by MITRE assessed the national airspace system (NAS) performance and developed metrics to assist decision-makers in allocating scarce resources to produce most benefits and continue to improve service offered by the FAA air traffic management (ATM) system (21). This study identified eight performance outcomes grouped into two main elements:
• User perspective
• Increase system capacity.
• Decrease system delays.
• Increase system flexibility.
• Increase system predictability.
• Increase user access.
• ATM service delivery
• Increase availability of critical systems and improve service delivery.
• Increase productivity.
• Create a model work environment.
Dynamics of Regional Airport System Development
As demand for air travel grows at major airports that are capacity limited, capacity expansion of the airport system at the metropolitan and regional levels becomes critical.
Increased use and expansion of secondary airports would be key to meeting future demand in capacity-starved airports of metropolitan areas. A study was conducted at MIT to explore the factors influencing the emergence of secondary airports and investigate the dynamics of multiairport regional systems (22). The study’s objectives were to evaluate the dynamics of emergence of successful secondary airports and identify proactive ways to accelerate the emergence of future underutilized regional airports.
The life cycle of airports in metropolitan areas starts with airport construction and the airport proceeds in several steps, as depicted in Figure 4.18. First commercial service commences at the airport, and when a particular carrier enters the airport, growth starts and the airport matures and grows until it becomes capacity constrained. At this stage search is initiated by industry to find a secondary airport to relieve the core airport.
To reflect this discussion on the entire United States, the national airport system was composed of 19,576 airports in 2004; 5280 open to the public mostly concentrated on the two U.S. coasts, correlated with distribution of population. Based on the 2009 NPIAS report (5), there are 19,815 airports; 5190 open to the public, of which 3411 are NPIAS airports— 386 of them are primary airports. Due to lack of land availability in metropolitan areas, opposition from local residents to building new airports, and development funding pressures, the number of airports has been reduced. Statistics of US Bureau of Transportation Statistics (23) have shown that certified public airports have been decreasing at a rate of four per year during the last 20 years at an annual
Airport construction
Initial phase
Initial commercial
service
Emergence phase
Capacity-constrained
airport Mature
airport
Traffic
Growth consolidation
phase
Entry of a specific carrier
Time Figure 4.18 Typical life-cycle and stages of airport evolution (22).
rate of –0.6%. For all public airports, there was an average loss of 36 airports per year, which implies that the current set of airports will have to accommodate the growth of air travel demand.
The MIT study (22) provided a systematic methodology to analyze, the emergence of secondary airports and criteria to identify active secondary airports within the U.S.
national airport system (NPIAS) (22). The identification and classification of secondary airports and the factors influencing their emergence were evaluated. The study inte-grated factors identified into the system dynamics model that was used to evaluate regional dynamics of multiairport systems. In order to do that, the top 30 highest vol-ume airports in the United States were selected. Of the 30 airports 26 “regional airport systems” were identified. (A regional airport system is defined as all airports within 50 miles of a reference core airport.) There may be more than one core airport within the same region (e.g., JFK, LGA, and EWR in New York–New Jersey area and IAD, DCA, and BWI in the Washington– Baltimore area). Within the 26 regional airport systems, there were 275 airports identified, but mostly they were small GA airports.
Table 4.3 and Figure 4.19 provide passenger enplanements and geographic locations for the 30 airports in the study.
Secondary airports were identified by analyzing traffic shares based on historical records of passenger enplanements as per the equation
T.S.RAS= enplanements at airport i
i∈A
enplanements at airport i
with A= {airports part of the regional airport system}
Airports with traffic share greater than 1% were considered to be core airports or secondary airports. Table 4.4 provides the percent share of core and secondary airports of their respective regional airport systems.
Table 4.3 Reference Airports for Case Studies (22) Passenger
Airport code Airport name enplanements
ATL Atlanta 37,224,000
ORD Chicago 31,483,000
DFW Dallas/Ft. Worth 27,581,000
LAX Los Angeles 24,007,000
MSP Minneapolis/St. Paul 18,944,000
DEN Denver 17,435,000
DTW Detroit 16,563,000
SFO San Francisco 16,431,000
PHX Phoenix 16,083,000
LAS Las Vegas 15,311,000
STL St. Louis 14,923,000
EWR Newark 14,904,000
IAH Houston 14,735,000
SEA Seattle 13,062,000
MIA Miami 12,721,000
MCO Orlando 12,529,000
BOS Boston 11,066,000
LGA LaGuardia 10,785,000
PHL Philadelphia 10,346,000
JFK Kennedy 10,137,000
CLT Charlotte 9,442,000
SLC Salt Lake City 8,709,000
PIT Pittsburgh 8,014,000
BWI Baltimore-Washington Intl. 8,002,000
CVG Cincinnati 7,610,000
SAN San Diego 7,248,000
TPA Tampa 6,912,000
IAD Dulles 6,830,000
DCA Reagan National 6,657,000
MEM Memphis 4,524,000
From the analysis of the traffic evolution patterns, airports were sorted based on their 2000 traffic and their historical role in the regional airport system.
Four airport categories were established:
• Core Airports (Original ). The initial airport in the region from historical and evolution standpoints.
• Core Airports (Emerged ). Airports that emerged while an original core airport was already in place and grew where traffic now exceeds passenger traffic of the original core airport.
• Secondary Airports. Airports with a traffic share between 1% and the traffic share of the core airport.
• Secondary Airports (Reemerged from Original Core Airport ). Airports that met the secondary airport criteria but were the original core airport in the system. At some point they lost traffic, then regained traffic and reemerged.
Figure 4.19 Map of the 30 selected U.S. regional airport systems (22).
Table 4.4 Passenger Traffic Share at Core and Secondary Airports (22)
Traffic share (based Traffic share (based Core airport on passenger traffic) Secondary airport on passenger traffic)
Miami (MIA) 69% Fort Lauderdale (FLL) 31%
Boston (BOS) 76% Providence (PVD) 15%
Manchester (MHT) 8%
Orlando (MCO) 95% Orlando Sanford (SFB) 3%
Melbourne (MLB) 2%
Tampa (TPA) 88% St Petersburg (PIE) 4%
Sarasota (SRQ) 8%
San Francisco (SFO) 64% Oakland (OAK) 17%
San Jose (SJC) 20%
Los Angeles (LAX) 77% Burbank (BUR) 6%
Ontario (ONT) 8%
Orange county (SNA) 9%
Long Beach (LGB) 1%
Washington National (DCA) 27%
Baltimore (BWI) 36%
Dulles (IAD) 37%
La Guardia (LGA) 27% Islip (ISP) 2%
Newark (EWR) 37%
JF Kennedy (JFK) 34%
Chicago O’Hare (ORD) 83% Chicago Midway (MDW) 17%
Dallas Fort Worth (DFW) 89% Dallas (DAL) 11%
Houston International (IAH) 79% Houston Hobby (HOU) 21%
Note: Core airports in bold characters are emerged core airports
Secondary airports in italic characters are secondary airports (re-emerged from an original core airport)
The other types of airports in the system fell into three other categories:
• General Aviation Reliever Airports. Airports that are generally located at the periphery of a major metropolitan area but serve as high density GA airports.
• Other Commercial and General Aviation Airports. Airports that did not meet the 1% traffic share. They are part of a larger set of surrounding airports that generally have GA activity and/or low volume of commercial traffic.
• Military Airports. Airports used for military purposes but characterized as joint civilian/military use airports.
Major factors identified by the study with emergence of successful secondary air-ports include congestion at the core airport, distribution of population at the regional level, existence and proximity of a secondary basin of population close to the sec-ondary airport, availability of airport ground access and infrastructure, and low level of connecting passengers at the core airport. The level of connecting passengers at the core airports is depicted in Figure 4.20.
Airport delays are an essential component of the level of service observed at the airport. From a customer perspective, poor level of service implies low airport attractiveness to passengers. The study found that there is correspondence between the congestion of the core airport and the existence of secondary airports in the system, and concentration at airports in the system generally correlates with the ranking of delays at airport.
60%
0%
STL DFW ATL IAH MSP PHL ORD DTW PHX MIA LAX SFO BOS EWR JFK LGA
Core airports Secondary airports
ISP
PVD, MHT
SJC, OAK
SNA, LGB, ONT, BUR
FLL
Secondary airports reemerging from an original core airport:
DAL HOU MDW
20% 40% 80%
Percentage of connecting passengers
Figure 4.20 Percentage of connecting passengers at core airports (22).
Table 4.5 Low-Cost Carrier Entries into Secondary Airports (22) Secondary airport Low-cost carrier Year of entry
Chicago Midway (MDW) Midway 1979
Southwest 1985
Fort Lauderdale (FLL) Southwest 1996
Providence (PVD) Southwest 1996
Manchester (MHT) Southwest 1998
Orlando Sanford (SFB) Melbourne (MLB) St Petersburg (PIE) Sarasota (SRQ)
Oakland (OAK) Southwest 1989
San Jose (SJC) Southwest
Burbank (BUR) Southwest 1990
Ontario (ONT) Southwest 1985
Orange county (SNA) Southwest 1994
Long Beach (LGB) jetBlue 2002
Islip (ISP) Southwest 1999
Baltimore (BWI) Southwest 1993
Newark (EWR) People Express 1980
Dallas (DAL) Southwest 1971
Houston (HOU) Southwest 1972
A more direct factor and an essential stimulus in the emergence phenomenon is the entry of an air carrier, generally a low-cost carrier (LCC). Entry of an LCC to secondary airports impacts the fares and energizes airport competition, resulting in market stimulation. As a result of LCC entry and the resulting fare competitiveness, these airports will soon experience rapid traffic growth. Table 4.5 lists the LCC entry into the airports selected in this study.
The analysis of what influences emergence of secondary airports indicated that the following factors play an important role in the emergence:
• Level of service at core airport, where congestion results in delays
• Availability of capacity at the regional level
• Distribution of population (density)
• Size of the local basin of population
• Airport infrastructure
• Political factors
• Connecting passengers at the core airport
• Entry of a LCC
The dynamic analysis of the study adopts the basic airport model built around the standard system dynamics approach using stock and flow diagrams and causal loops.
The stock and flow diagram starts with the demand for air transportation and then distributes this demand through the actual passenger enplanements if the demand is
materialized. If not, the demand is spilled and flows to substitution modes of trans-portation (e.g., car, train). If the demand is still not materialized in any of the available modes of transportation, it is simply “spilled,” and the potential passenger chooses not to travel.
Factors identified in the analysis of emergence of secondary airports were included in those causal loops. They are basically centered on two main composite variables:
the airport attractiveness to airlines and the airport attractiveness to passengers.
In this study, two model subparts (core and secondary) were developed where inputs to both could describe real-world interaction between both subparts. Figure 4.21 schematically represents these two subparts in the system dynamics model:
• The core airport congestion model (congestion/capacity inadequacy), where the core airport congestion model is triggered by the lack of supply (capacity) at the core airport. It impacts negatively the attractiveness of the core airport to passengers, which translates into an increase in regional airport attractiveness to passengers. However, this attractiveness will only materialize in actual enplane-ments and operations if an airline is willing to enter this airport.
• The local market demand model (local market/unmet demand) is triggered by the unmet demand at the local level. It directly impacts the attractiveness of the secondary airport to airlines. A carrier that decides to enter this market and serve this unmet demand will trigger both the stimulation and the airport growth loops, resulting in the emergence of the secondary airport.