National Academies Press: OpenBook

Guidebook for Planning and Implementing Automated People Mover Systems at Airports (2010)

Chapter: Appendix A - Theoretical Examples of APM Planning and Implementation

« Previous: Bibliography
Page 119
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 119
Page 120
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 120
Page 121
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 121
Page 122
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 122
Page 123
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 123
Page 124
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 124
Page 125
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 125
Page 126
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 126
Page 127
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 127
Page 128
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 128
Page 129
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 129
Page 130
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 130
Page 131
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 131
Page 132
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 132
Page 133
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 133
Page 134
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 134
Page 135
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 135
Page 136
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 136
Page 137
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 137
Page 138
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 138
Page 139
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 139
Page 140
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 140
Page 141
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 141
Page 142
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 142
Page 143
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 143
Page 144
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 144
Page 145
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 145
Page 146
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 146
Page 147
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 147
Page 148
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 148
Page 149
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 149
Page 150
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 150
Page 151
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 151
Page 152
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 152
Page 153
Suggested Citation:"Appendix A - Theoretical Examples of APM Planning and Implementation." National Academies of Sciences, Engineering, and Medicine. 2010. Guidebook for Planning and Implementing Automated People Mover Systems at Airports. Washington, DC: The National Academies Press. doi: 10.17226/22926.
×
Page 153

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

119 Introduction This appendix presents two theoretical examples of the planning process for an APM system at an airport. The exam- ples demonstrate applications of the methodologies and plan- ning criteria in the guidebook to produce plans for two APM systems. It also describes the applicable metrics and measure- ment tools to both qualitatively and quantitatively evaluate the alternatives and select an optimal solution. The two examples in this appendix consist of a pinched-loop system and a shuttle system. These are two common types of APM system configurations, and their examples demonstrate the APM technology considerations from Chapters 6 and 7, as well as the planning criteria of Chapter 8. These previous chap- ters, particularly Chapter 8, should be consulted in conjunction with this appendix. The focus of this appendix is on the process of APM planning more than on the technical design details of an APM system presented in the chapters. It should be noted that while the two theoretical examples have some clear differences (airside vs. landside, shuttle vs. pinched loop, etc.), there are some planning steps that are sim- ilar; therefore, there are some sections in this appendix where the text is repetitive between the two examples Flowcharts Throughout the description of the APM planning process, this appendix provides both summary and detailed flowcharts outlining the planning processes for two theoretical airport APMs; a self-propelled airside pinched-loop system and a cable- propelled landside shuttle APM system at a hub airport. The flowcharts highlight the similarities as well as the differences in the planning process between the two examples, and include a graphic key. Many findings have been made throughout the planning process for each example. These findings appear in the flowcharts as decisions (diamonds) and were arrived at through an analysis of existing APM systems with similar characteristics to these theoretical systems. Outputs of the “Operations & Maintenance Costs,” “Capital Costs,” and “Evaluate System Level of Service” process blocks are shown as data outputs (par- allelograms) rather than decisions (diamonds). This was done to show that costs and level-of-service measures are fixed out- puts based on the many decisions that are made during APM system planning. Once the system parameters are defined, cost becomes a fixed output (although in practice system parameters may be re-defined to meet cost limitations). Level of service also becomes fixed once system parameters are defined, but the flowchart shows a dashed line connecting level of service to all system-defining decisions. This was done in order to show how level-of-service considerations influence sys- tem parameters throughout the planning process and may be used to fine tune system parameters. Although the flowcharts are intended to be self-explanatory, this appendix’s text is offered as a supplement and amplification of the planning actions depicted in the process boxes (squares) contained in the flowcharts. These can be categorized into three main categories, with major issues within each category bulleted as follows: 1. Operational considerations: • System level of service • Alignment • Ridership • Capacity analysis 2. Technical considerations: • Power distribution • Maintenance and storage facility analysis • Command, control, and communications analysis • Station and passenger flow analysis 3. Cost considerations: • Operations and maintenance costs • Capital costs • Cost–benefit analysis • Financial strategies A P P E N D I X A Theoretical Examples of APM Planning and Implementation

A summary APM planning flowchart is provided below as Figure A-1 and depicts the general airport APM planning process applicable to both the airside and landside exam- ples. More detailed zoom-ins of the general flowchart are provided at appropriate places within this appendix to illu- minate specific issues in the airside and landside planning processes. Assumptions The flowcharts depict the planning process specifically for an APM system and assume that the airport has already come to the conclusion that they wish to plan an APM system. The charts do not include any reference to other technologies that might be considered as alternatives to an APM such as shut- tle buses. It is assumed that any such alternatives have already been eliminated through an earlier multimodal alternatives analysis or are not of interest to the airport. All flowcharts assume that the APM system is being planned for implementation at an existing airport as opposed to being part of an airport’s initial construction. This assumption is made to reflect the most common scenario likely to face those planning the APM. Although the most recent APM planned as part of the initial construction of a major airport in the United States was at Denver International Airport, which opened in February of 1995 and is not likely to be repeated, other airports outside of the United States are implementing APM systems as an integrated part of initial construction. An example, occur- ring as this guidebook is being produced, is the New Doha International Airport in Qatar. For these rarer examples of new greenfield construction, the planners should proceed with the self-evident assumption that certain processes described in the flowcharts will be considerably less constrained, particularly those dealing with physical and spatial issues such as the guide- way alignment and the location of the maintenance and stor- age facility. Closer examination of the similarities and differences between the two flowcharts reveals more similarities than differences. This is indicative of the conceptual common- ality in the planning process for APMs of different config- urations. Because of this fact, it can be assumed that the planning process documented in this appendix for Examples 1 and 2, the airside pinched-loop APM and the landside shuttle APM, respectively, can serve as a basic blueprint for the planning of many airport APMs of different configura- tions. There will be some differences among different APMs and the planning processes for the two examples reveal some of these differences. These differences can serve to typify the number, degree, and types of differences that would likely be encountered when planning for different APM systems at an airport. Example 1: Planning an Airside Pinched-Loop APM System For this discussion, refer to the Figure A-1 flowchart for a summary level process as well as the detailed flowcharts (Fig- ures A-2 through A-6) referenced within certain sections. This discussion follows the more-detailed flowcharts; italicized notes provide cues for the reader to refer to specific aspects of the detailed flowcharts. For Example 1, the first detailed flowchart (Figure A-2) com- mences with stating the principal need: “Airport wants to inves- tigate an APM to provide service between terminals to benefit transfer passengers.” For airside APM systems, it is the transfer passenger that typically drives the need for an APM system. Specifically, for large hub airports, it is common for an airport to grow or develop a master plan for growth when: 1. The distances between connecting gates become too great to be traversed by unassisted walking or moving walkways within the allotted online or interline connection times; and/or 2. The location of connecting gates becomes segregated or separated by airfield elements (runway) or other elements whereby surface transportation, such as buses, cannot operate. Although the assumptions for this appendix state that an APM has already been selected over alternate systems such as a busing system, the point of this discussion is to stress that air- side APM systems can often be easily justified. For example, the two preceding conditions (1) and (2) leave virtually no choice but to plan for an APM. In smaller, non-hub airports, an air- side APM may also be justified by the convenience and/or level of service provided to the passengers. Operational Considerations A prerequisite for the successful planning of an airside APM is to plan the system around project-specific operational con- siderations and not to plan the system around a specific APM technology and its characteristics. The following discussion amplifies the operational considerations listed in the process blocks of the flowchart. System Level of Service • Determine the level of service priorities based on the air- port’s goals and objectives. One may initially assume that all APM systems should strive to be designed to offer the highest level of service possible. However, this is not neces- sarily the case. An example is to compare a must-ride system such as Denver International Airport’s (DIA) APM with the concourse tram APM at Minneapolis International 120

Level-of-Service Decision-Making Flow Key: Process Data Output Start/ End Planning Process Decision-Making Flow APM Benefits Alignment Stations Guideway/ROW Capital Costs Operations & Maintenance Costs Cost–Benefit Analysis Financial Strategies Power Distribution Command, Control, and Communications Ridership System Capacity NEED System Level of Service Evaluate System Level of Service Evaluate System Level-of-Service Measures Environmental Final Design Procurement Defined APM System Functions Served Service Req’ts. Maintenance Facility Walk & Time Thresholds Source: Lea+Elliott, Inc. Figure A-1. Summary airside APM planning process.

Airport (MSP). The DIA system was planned with a level of service in terms of redundancy, headway intervals, and availability that were all more critical than for the MSP sys- tem because it provides the sole means for passengers to reach their gates. The MSP system provides an appropriately high level of service, but was planned with the consideration that passengers have the option of walking or taking moving walkways to their gates if desired. Thus, certain level-of- service factors (such as redundancy) were not as important. Other level-of-service planning criteria include: • Passenger density and crowding. Passengers choose to stop boarding a train when they perceive that the train is full. Thus, although it is not possible to assume passengers will crowd onto a train, certain planning parameters can result in different levels of density on the station platform. As such, the acceptable level of density should be determined from a planning standpoint. The options span from planning for minimum waiting times with virtually no passenger queue to (in rare cases) actually assuming missed trains are acceptable during peak hours. • Passenger effort, including level changes and walk dis- tance. A generally accepted planning assumption is that fewer level changes are desirable because level changes not only increase passenger effort (even with escalators) but also inhibit passenger wayfinding. A general planning assump- tion is that less walk distance is desirable. In some loca- 122 Source: Lea+Elliott, Inc. Figure A-2. APM operations planning process.

tions, walk distance is defined as the distance the passenger actually walks, not the distance the passenger travels (while standing on moving walkways for example), while in other locations, planners sometimes assume that passengers walk on moving walkways. • Ride comfort, including lateral forces and acceleration/ deceleration. Such forces are typically specified in terms of allowable maximums set by pre-established industry stan- dards. These standards exist not only for comfort, but for safety. However, in certain cases, exceptions may be made. For example, when particular guideway alignment options dictate a vertical grade beyond normal practices, certain ride comfort factors will be degraded. • Passenger wayfinding, ease of use, and system simplicity. A generally accepted planning assumption is that simplicity of wayfinding is desirable. Specifically, minimizing the num- ber of decision points that the passenger must make is desir- able. All APM systems require audio and visual (signage) cues because they typically require self-use by the passenger, without attendants. One widely accepted way to effectively use directional signage is to avoid referring to the APM sys- tem except when absolutely necessary. For example, passen- gers are simply signed to their appropriate gate, and the train ride to that gate becomes incidental. Alignment • Determine station locations and area constraints. Plan- ning for the number, spacing, and placement of the sta- tions should provide the maximum convenient service to the largest range of users with the fewest possible number of stations. Planning for the fewest practical number of stations needed to provide the appropriate level of service helps the economy and efficiency of the system in terms of fleet size and reduces the capital and O&M costs of both the APM sys- tem and the associated fixed facilities. Planning for future potential expansion must also be incorporated. • Create alternative alignments to connect stations. The actual guideway alignment is a means to an end. The end is to serve the stations that have been located to meet various project-specific parameters. The most efficient guideway alignment is typically one that is perfectly straight and per- fectly level, but in real-world planning it is seldom possible to provide such a guideway, particularly when introducing an APM into an existing airport environment. However, there is typically an optimal geometrical guideway align- ment to connect the planned stations, and the most effective way to determine such an alignment is to evaluate a range of different alignments. • Evaluate alignments in terms of level of service, potential cost, and efficiency to determine preferred alignment. Using the different alternate alignments that have been developed, consider how the level of service, cost, and system efficiency are affected by the specific differences in the alter- natives. These differences may include aerial versus subgrade and/or combinations of aerial and subgrade alignments. Additional areas for evaluation include the alignment’s impact on existing facilities, impact on future growth poten- tial, ease of expandability, and ease and/or possibility of phased implementation. Specifics regarding the alignment configuration should also be evaluated, particularly for asso- ciated cost implications. For example, in a dual-lane system, bringing the two guideways close together where possible along the alignment allows shared use of a single, central emergency walkway as opposed to having two separate emer- gency walkways. Also, the supporting structure will typically be more economical due to reduced forces in the columns, bents, and foundations when the distance between two par- allel guideways can be minimized. • Determine preferred guideway configuration (shuttle, pinched loop, etc.) base on level of service and cost. Somewhat simultaneously with the exploration of various guideway alignments, various configurations of the guideway should also be developed at a conceptual level. For instance, a two-way loop configuration may provide the needed level of service, but further exploration may reveal that a pinched- loop configuration provides an equal level of service yet gains an economic advantage by not needing the construction of as much guideway in terms of single-lane feet. For an airside hubbing application, the number of airline gates to be connected often dictates three or more APM stations, and the required gate-to-gate connect times dictate very low headways. This combination of longer distance and shorter headways typically results in selection of a pinched- loop guideway configuration. • Allow for potential propulsion technologies (cable- propelled, self-propelled). Some aspects of a guideway’s alignment have differing effects on different propulsion technologies. For instance, LIM propulsion is typically more sensitive to grades. Also, certain cable technologies are more sensitive to vertical curves (particularly concave or “sag- ging” vertical curves) because the cable may lift from the sheaves in certain instances. More detailed design analysis is required to confirm and/or solve such specifics, but the planner should be aware of such issues even in the early planning stages of the APM. As noted in the guideway configuration paragraph above, an airside hubbing application typically requires an alignment length and system frequency that dictates more than two trains operating, and therefore a self-propelled technology operating on a pinched-loop configuration. The reader is encouraged to note the decision diamond in the Figure A-3 flowchart where the theoretical airside system has 123

124 Source: Lea+Elliott, Inc. Figure A-3. APM capacity planning process.

now been planned as a self-propelled, pinched-loop system with 3 stations and 1.5 miles of underground dual-lane guideway. The decisions reached for this theoretical example (self-propelled, pinched-loop, underground, etc.) are common decisions found in actual airside APMs at large hub airports with many transferring passengers. Specific decisions at each airport depended on the site- specific environment. Reasons for the decisions in our theoretical example may be as follows: • Self-propelled and pinched loop—At a large hub airport there are multiple terminals being connected via the APM, and the relatively long alignment (and high service frequency require- ment) dictates multiple trains in operation and therefore a pinched-loop alignment and self-propelled technology. • Underground—At a large airport with multiple terminals separated by an active aircraft apron, an underground align- ment is typically the only solution. Ridership • Determine gated flight schedule for the design day. The airlines’ current or projected flight schedules are key instru- ments in answering the basic ridership questions of how many people need to go where and when. However, answer- ing these basic questions is seldom simple because airlines may not have flight schedules projected into the appropri- ate future years, and if they do, their accuracy is always uncertain due to inevitable change. Thus, it is accepted that the planner must take a conservative approach in ridership calculations, erring on the side of higher ridership when pre- sented with unknowns. This is borne out by the fact that all APM systems at major airports have consistently incurred increased ridership over time, whereas this has not univer- sally been the case with APMs in urban settings. • Apply factors for aircraft boarding rates, walk speeds, gate- to-station distances, terminal corridor flow capacities, and vertical circulation capacities. Such factors are fairly stan- dardized and accepted among aviation and transportation planners. These standard factors should be used unless spe- cial circumstances dictate otherwise. • Use simulation software to determine ridership volumes between each station for any time increment of the design day. This is a specialized task that is most appropriately assigned to an entity with the tools and experience to calcu- late the ridership volumes between each station, the deboard- ings and boardings at each station, and the system’s peak link. In addition to the design hour of the design day, ridership is typically analyzed and determined for a variety of off-peak hours in order to accurately estimate how the APM system will operate throughout a typical 24-hour period. • Determine average passenger area requirements (bag- gage). This varies by project, particularly between airside and landside systems. Passenger area requirements are expressed in area (square feet or square meters) for each standing and seated passenger, respectively. In the case of the theoretical airside system, it is assumed passengers will have smaller, wheeled carry-on bags onboard the trains, and the space per passenger should be calculated accord- ingly. Changes to airport security requirements (carry-on baggage) and to baggage design (size, roller capability, etc.) require planners to continually update these passenger area requirements. The reader is encouraged to note the decision diamond in the flowchart in Figure A-3 where the theoretical airside system has now been planned to provide for 3.3 square feet per passenger based on known ridership volumes between each station throughout the design day and the number of station deboardings and boardings. Capacity Analysis • Determine generic APM technology. The actual technol- ogy of an actual APM supplier is not assumed for this step. Rather, the planner should determine/develop a generic APM technology that is generally representative of several actual APM suppliers. This will help ensure healthy compe- tition among multiple suppliers that may ultimately provide a system in accordance with the performance specifications to be developed during the design phase and after the plan- ning phase of the system is completed. An example involv- ing generic APM technology would be the assumption of using a generic 40-foot vehicle because many APM suppli- ers produce a vehicle close to a 40-foot length. Good knowl- edge of the major APM supplier’s technology is crucial for the exercise since some are configured in married pairs while other suppliers only offer vehicles less than 40-feet long. • Simulate train performance over alignment to determine round trip time (RTT). This typically requires the use of specialized computer modeling in all but the most simply configured APM systems. As performance does vary among technologies, it is best to assign train performance simulation to an entity with experience in this specialized field. • Determine vehicle capacity using average passenger space requirements. In this planning task, the generic 40-foot vehicles can be assumed to accommodate a certain num- ber of standing and seated passengers based on the planned 3 to 4 square feet per passenger—say 3.3 square feet per passenger. • Calculate the train headway (round trip time headway  number of trains). This calculation is self explanatory. Although the RTT and headway (HW) can be accurately modeled and estimated, a certain amount of professional judgment and expertise should be applied. For example, in calculating the RTT, inputs to the simulation model should 125

consider that the particular dwell times at different stations may differ, and their durations should be estimated. For instance, a lightly loaded station may function well with dwell times as low as 20 to 30 seconds, whereas a heavily loaded station may typically require dwell times exceeding 1 minute. Switch location is an important factor in the round trip and HW calculations. • Determine range of capacities for range of train consists. For this planning task, a variety of APM performance crite- ria must be considered together in order to ensure that the most efficient system is developed. For example, it may have been determined that the minimum calculated HW is not necessary to achieve the desired level of service. Yet it may also be determined that by using the absolute minimum HW, four trains would be able to operate instead of three trains. Assuming the generic 40-foot vehicles, it may also be determined that the required capacity could be attained by running four two-car trains instead of three-car trains. Note the positive domino effect resulting from the differ- ence in these train consists: the total operational fleet can be reduced from nine to eight vehicles, all station platforms can be reduced in length by 40 feet, and the number of plat- form automatic door sets can be reduced by two or three sets per platform depending upon the actual supplier—all with no reduction in capacity but actually with an increase in level of service due to the shorter headways. • Compare ridership demand to capacity range and deter- mine appropriate peak-period capacity. This task deter- mines the peak link during the peak period of demand. The peak link is defined as the link between successive stations that has the highest ridership demand. Although other links between stations will have less ridership demand, it is the single peak link that drives system capacity. • Size APM operating fleet over the entire design day (peak, off-peak, night). Because ridership demand varies over the day, the capacity of the APM system should be adjusted to match demand to the greatest degree that is possible. Hav- ing more trains in operation than is necessary during an off- peak period incurs unnecessary wear and tear on the trains and related equipment, shortens major and minor main- tenance intervals thus increasing maintenance costs, and incurs unnecessary power consumption. Therefore, the operating fleet should be planned to accommodate differ- ent ridership demand scenarios over the design day, and if possible, also accommodate seasonal ridership differences and holiday peak periods that may last from a few days to a few weeks. There are also energy-saving opportunities dur- ing off-peak and night operations that can be achieved with a detailed power consumption (load flow) analysis. The reader is encouraged to note the decision diamond in the Figure A-4 flowchart where the theoretical airside system has now been planned for a 6000 pphpd capacity to be met with a 24-vehicle fleet with three-car trains (40 feet per car = 120-foot train length) operating during peaks at 2 to 3 minute headways. Technical Considerations The successful planning of an APM also involves consider- ation of technical aspects of the system. Each APM system is proprietary and is therefore unique with regard to many par- ticular technical aspects. The challenge to the APM planner is to appropriately plan the system in accordance with known technical considerations yet not to a degree so specific that certain suppliers are unable to provide a viable system. This increases competition, which is in the best interests of the air- port. The following discussion amplifies the technical consid- erations listed in the process blocks of Figure A-4. Power Distribution • AC or DC propulsion power distribution? Although the actual onboard traction motors that propel APM vehicles are universally AC, the propulsion power distribution sys- tem that provides power to the vehicles along the guideway may be AC or DC, depending on the particular supplier. Although there are advantages and disadvantages to each, from a planning perspective it is not useful to assume one is better than the other or to attempt to predict which will be used. Rather, it is important for the planner to under- stand the differences between the distribution systems that affect the high-level planning of the system. For instance, power distribution substations for a DC system can be located further apart than those of an AC system. More and larger equipment within the substation is required for DC systems. Thus, substation space requirements will be greater for DC systems. DC ground current is of greater con- cern than that of AC, and may require corrosion control measures and current testing facilities that are not required for AC systems. • Determine system power demand based on headways and train consists over the course of the design day. The system’s power demand will be used in O&M budgetary planning by the airport and will also be needed by the local utility company that will provide the high-side power to the APM. The power demand may be manually derived for small systems, but computer modeling of power demand is virtually essential for larger systems with multiple trains and changing train consists. • Based on system power demand, determine the location, size, and number of power distribution substations. This is where some of the differences in planning for an AC or DC system will come into play. However, regardless of AC or DC power distribution, some planning rules of thumb 126

127 Source: Lea+Elliott, Inc. Figure A-4. APM technical planning process.

are applicable. Generally, the substations should be located directly adjacent to the guideway if possible. If multiple substations are required, their general locations should be located equidistantly along the guideway, and equidistant from each other to the degree possible, in order to minimize voltage drops and increase efficiency. Each substation will require access for equipment and personnel, including on- site parking and loading areas. Housekeeping power to the substations must also be planned for. Energy storage (i.e., captured through regenerative braking) equipment should also be considered. • Coordinate design and construction of the power distri- bution system with the local utility company. This task involves coordinating the layout of the physical aspects of the power distribution system. For instance, the local utility company may provide and install the power service entrance or what is sometimes referred to as the distribution yard. In addition, certain electrical design aspects of the distribution system must be coordinated with the local utility company. For example, regenerative braking enhances energy effi- ciency by capturing braking energy and feeding it back to other trains or back to the utility. However, some utility companies will not allow this. AC systems are more likely to induce harmonic noise on the utility distribution lines. This may require harmonic filtering, and this should also be coor- dinated with the utility company. The reader is encouraged to note the decision diamond in Fig- ure A-4 where the theoretical airside system has now been planned as a 600 volt AC system with four power distribution substations located approximately every 2,000 feet. Maintenance and Storage Facility Analysis • Determine size of facility based on space requirements for maintenance bays, enclosed workshops, administration areas, and personnel areas. For larger systems configured in a loop or pinched loop, the MSF is offline and typically includes an adjacent storage and switching yard. (Shuttles tend to have online MSF at a terminus station.) Maintenance bays for an offline MSF include heavy and light bays where long term and short term maintenance tasks are performed, respectively. Although the MSF is a specialized building type, architectural and engineering firms require no specialized expertise to design and produce the construction documents for the MSF once it is programmed. However, it is this archi- tectural programming that is critical to the success of the MSF. Planning for the MSF should also consider any possi- ble expansion of the system. • Determine MSF location (online or offline) based on fleet size and system length. An offline maintenance facility is typical for multi-station, pinched-loop systems and should be located adjacent to a mainline guideway so that a mini- mum amount of non-revenue guideway is required for access. APM maintenance facilities are unlike a bus main- tenance facility in that they are clean and quiet (because internal combustion engines are not involved). Thus, from a planning perspective, the MSF may be located in sensi- tive areas, such as within an airport terminal building, without negative impacts. • Provide a route for delivery of materials to the facility. This includes site access that can accommodate trucked deliver- ies, including full-size tractor-trailers on occasion. A route for material delivery applies not only to the siting of the MSF but to circulation within the facility itself. Planning should dimensionally accommodate a forklift with pallets in and around all maintenance bays, including a path to parts stor- age or other accessed areas. Planning should accommodate delivery and storage of items that will not fit within a freight elevator. One example is replacement power and signal rail, which typically comes in 40-foot lengths. • For offline facilities, determine the alignment of the ready and receiving tracks and the test track. The ready (or departure) track and the receiving track are sections of guideway located between the mainline guideway and the offline MSF yard. These tracks function as hand-off or transition areas for trains leaving and entering the main- tenance yard to and from revenue service. The ready track is the staging position for a fully serviced and powered train that is ready to be inserted into revenue service at the desired time. The receiving track is the section of guideway where a train is handed from revenue service into maintenance. This transition is both physical and electronic, involving both the automatic train control system and mainte- nance staff. From a planning perspective, the significant requirement is that both of these guideway areas must accommodate a train of maximum length and ideally, although not absolutely, should consist of tangent sections of guideway. The test track is a non-passenger-carrying section of guideway where dynamic testing of trains can be per- formed before putting them into passenger-carrying serv- ice. Ideally, the test track should be tangent and of a length that allows a maximum length train to reach maximum speed. For a four-car train of generic 40-foot vehicles, this length is approximately 1000 feet. From a planning perspec- tive, if space is at a premium, a shorter test track is superior to no test track. The reader is encouraged to note the decision diamond in Figure A-4 where the theoretical airside system has now been planned to include a 40,000 square foot offline maintenance facility, 0.2 dual-lane miles of ready/receiving track, and 0.2 dual-lane miles of test track. 128

Command, Control, and Communications Analysis • Determine the space and equipment requirements of the central control facility. The size and layout of the CCF varies somewhat in proportion to the size of the APM sys- tem. However, all CCFs have basic requirements that must be planned for. These include a control console with system mimic screens, and CCTV monitors for station (and possi- bly other) surveillance, all within sight of the central control operators. Typically, an APM equipment room is located directly adjacent to the CCF. The specific requirements for the equipment and layout of the facility must be considered to ensure that an adequate spatial footprint is reserved in the planning stage. The CCF should be planned to accommodate additional equipment and/or personnel required for future expansion of the system if such expansion is anticipated. • Determine the location of the facility. From a planning perspective, combining the CCF with the MSF (locating the CCF within the MSF) is typically a solution that allows functional consolidation and efficiencies. If the CCF is located remotely from the MSF, some duplication of min- imum essential facilities such as restrooms and adminis- trative space may be required. The initial location planned for the CCF should be considered its permanent loca- tion, and any possible expansion or changes to adjacent or surrounding facilities that could cause disruption to the CCF should be considered when choosing this loca- tion. Although CCFs have been successfully relocated, the CCF is the electronic center of the APM system; thus, such relocations are difficult, expensive, and invariably cause significant operational disruptions. • Determine staff requirements for Central Control Oper- ators. Adequate staffing and the number of CCOs should be considered with project-specific requirements. As a gen- eral rule, a minimum of two CCOs should staff the CCF at any time. The total number of CCOs on staff will depend upon system size, shift arrangements, and benefit (partic- ularly leave) factors. The reader is encouraged to note the decision diamond in Fig- ure A-4 where the theoretical airside system has now been planned to include a 2,000-square-foot CCF located within the MSF with redundant workstations for ATC, SCADA, and communications with a minimum of three CCOs on duty. Station and Passenger Flow Analysis A prerequisite note regarding the following bullets is that architectural programming and analysis is critical to the suc- cessful planning of the stations. Also, reference Section 8.4, Stations, for additional detailed discussion regarding the pro- gramming of APM stations. • Determine minimum platform length using maximum period train consist length. Various queuing areas for pas- sengers must be taken into account when the total platform length is determined. These include queues for the trains, as well as for escalators and elevators. If future expansion plans call for increasing the number of vehicles per train, then the platform must be sized to accommodate this future train length. In these cases, the automatic station doors for the future vehicles are typically not installed, although their posi- tions are reserved by removable window wall assemblies or some type of removable panels. In some instances, the future automatic station door sets may be procured and installed prior to their actual activation. • Define desired level of service in terms of passenger queue area and circulation area. This level of service can range from planning for virtually no waiting queue to, in rare occa- sions, missed trains being an acceptable situation during peak periods. For an airside APM serving hubbing airline passengers, the prospect of missing an APM train due to crowding would not be acceptable due to the time sensitiv- ity of gate-to-gate travel. In all cases, passenger queue area depends upon the headways of the trains to a large degree, and thus should be planned in conjunction with the trains’ performance parameters. The circulation on an APM plat- form typically implies circulation paths to and from the trains and to and from vertical circulation elements only. This is because no other functions typically exist on the plat- form. For instance, it is not recommended to install seating, vending machines, newspaper racks, telephone banks, flight information display systems (FIDS), or other such amenities on an APM platform. The short wait times on the platform do not permit use of such amenities without interfering with the primary purpose of the platform, which is to quickly and efficiently move people on and off the trains. • Determine minimum platform width based on vertical circulation requirements and desired level of service dur- ing peak demand. This is a particular topic for which the reader is encouraged to review Section 8.4, Stations, for additional discussion. For larger APM systems serving an airline hubbing operation, it is likely that the queuing requirements for large numbers of passengers waiting for the trains will become the determining factor in establish- ing the minimum platform width. Also, the type of station is a key factor in determining minimum platform width. For example, a center platform station has a single area that must accommodate two functional platforms for trains arriving on either side. This single platform accommodates both boarding and deboarding passengers, and the fact that two trains may arrive at the same time must be con- sidered. Side platform stations have platforms that accom- modate only one train each, but each platform must have a full complement of vertical circulation elements and must 129

accommodate both boarding and deboarding passengers. A triple platform station (also referred to as a “side-center- side” or “flow-though” station platform) has three separate platforms, each with a full complement of vertical circula- tion elements. In this case, the center platform serves as a boarding platform only and the two side platforms serve only as deboarding platforms. The automatic door sets for the deboarding platforms open several seconds before the door sets for the boarding platform. This establishes the proper queue movement and allows the fastest and most efficient boarding and deboarding of the train, although this station type is the most expensive and requires the most overall space. • Determine NFPA 130 compliance. An excellent guide for life safety issues is the National Fire Protection Associa- tion’s “NFPA 130—Standard for Fixed Guideway Transit and Passenger Rail Stations.” Its content is well researched and is dedicated to specialized life safety issues. For exam- ple, the NFPA 130 test for emergency egress from a station is not a typical/historical building code occupancy type analysis but rather an analysis of time, distance, and pedes- trian movement that accurately reflects the real-world sit- uation on the station platform. The reader is encouraged to review Section 8.4, Stations, for additional discussion on this topic. Egress from an underground airside APM sys- tem is of critical importance because passengers cannot be brought up to an active airfield apron. • Develop and evaluate alternative station configurations and vertical circulation locations to determine the pre- ferred station layout and size. The guidelines given in this appendix and in Section 8.4, Stations, provide only an overview of basic APM station design parameters. An archi- tect, in collaboration with an APM specialist, should fully explore different station configurations within the context of project-specific and site-specific factors in order to develop the most appropriate specific station design(s). The reader is encouraged to note the decision diamond in Fig- ure A-4 where the theoretical airside system has now been planned to use side-center-side platforms approximately 120’ long, with each platform having one elevator, one open stair (in addi- tion to any required fire exits/stairs), and two single-direction escalators. Cost Considerations A variety of costs must be considered in the successful plan- ning of an APM system. These costs include the initial capital costs required to implement the APM as well as the ongoing operations and maintenance costs of the system. In terms of APM planning, a cost–benefit analysis is recommended as a litmus test of the overall viability of the APM system. This sec- tion focuses primarily on APM system costs and not the costs of the system’s associated fixed facilities. This is because the costs associated with the APM system’s fixed facilities can be estimated by a professional estimating firm with no particular differences from other similar building types. The APM system costs, on the other hand, vary widely within the APM industry because each different APM supplier uses a different and pro- prietary technology. Costs for different projects by the same supplier may also vary significantly because of different scales of economy involving fleet size, capacity requirements, level of bid competition, and so forth. Thus, estimating and com- paring the cost of a proposed APM system against standard industry costs is difficult because repeatable and consistent costs within the industry are quite elusive. The following discussion amplifies the cost considerations listed in the process blocks in Figure A-5 and offers relevant points to be considered in preparing system cost estimates. Operations and Maintenance Costs • Gather historical data on APM operations costs at simi- lar airport applications. A key consideration is to ensure, to the greatest degree possible, the similar nature of the APM systems for which the data is being gathered in terms of all operational and technical parameters. Since no two APM systems are identical, it is best to select a set of sys- tems as similar to each other as possible and then adjust the O&M costs according to the known differences from the system being estimated. • Adjust historical data for airport-specific factors. These fac- tors can include the likelihood of union or open-shop labor and the associated local labor rates by category. Another airport-specific factor is the party that is intended to perform the O&M services, both initially and in the future. Options could include the initial supplier, a possible third-party provider by way of competitive bids, or the airport’s own in- house staff. • Determine annual fleet mileage and fleet size based on operating fleet over the design day (see the Capacity Analy- sis section). Factors considered in the capacity analysis must also be considered in determining the fleet mileage, which determines the wear and tear on the vehicle fleet, which in turn determines the frequencies of major and minor main- tenance intervals. • Derive energy, consumables, and parts consumption from the annual fleet mileage and historical data. Some additional options for the airport to consider are how and where particular O&M costs will be accommodated and budgeted for. For example, parts and consumables may be included in the annual budget for an airport’s mainte- nance department, whereas the electrical costs for system operations may be included in the annual budget of an airport’s utility department. 130

• Derive staffing and management requirements based on fleet size, mileage, and historical data. Staffing for the APM system will consist of several different categories, and staffing will vary in proportion to system size and complexity. There are typically three work shifts that provide 24-hour coverage of the system 365 days per year. “First shift” typically refers to the shift most closely approximating 8 a.m. to 5 p.m. “Third shift” typically refers to the overnight shift, when the system is operating off-peak and wayside and other main- tenance tasks are best accomplished. “Second shift” typi- cally encompasses the 8 hours between first and third shifts. Staff categories typically consist of administrative and man- agement, operations, and maintenance. The administra- tive staff typically includes a site manager and secretary or 131 Source: Lea+Elliott, Inc. Figure A-5. APM cost–benefit planning process.

other clerical positions. Administrative staff typically works first shift. Operations staff typically includes the central con- trol operators as well as mechanics and mechanics’ helpers. Operations staff must cover all three shifts. Maintenance staff typically includes electrical technicians, mechanical technicians, and their helpers. Although there is typically shift overlap between operations and maintenance staff members, most of the work of the maintenance staff is usu- ally done during the third shift. • Include contingency and other factors to determine the O&M cost estimate. The total O&M cost estimate will include factors such as contingency, escalation, overhead, and profit, and these factors are best determined and applied on a local and project-specific basis. Whether such factors are applied “above the line” or “below the line” in terms of labor and material subtotals is also best determined by the typical practices of the specific location and project. Capital Costs • Gather detailed historical data on systems costs of simi- lar airport APM implementations. A key consideration is to ensure, to the greatest degree possible, the similar nature of the APM systems for which the capital cost data is being gathered. Since no two APM systems are identical, it is best to select a set of systems as similar to each other as possible and then adjust the capital costs according to the known differences from the system being compared. • Adjust historical data for airport-specific factors. These fac- tors can include the likelihood of union or open-shop labor and the associated local labor rates, by category, for appro- priate building or highway labor categories. Other airport- specific and location-specific factors include local and national cost and/or availability of materials, local inflation and unemployment rates, and specific bonding requirements as well as the associated costs of procuring such bonds. • Estimate the cost of each subsystem or element of the APM system based on normalized historical data. Breaking the estimated costs down by system and major subsystem facili- tates the comparison, possible negotiation, and the recon- ciliation of estimated costs with the proposed actual costs. Within the APM industry, there are fairly standardized breakdowns for both system estimates and the supplier’s pro- posed costs. Although the total scope of these breakdowns is beyond the scope of this guidebook, the following are some major, industry-accepted breakdown categories: guideway facilities; station facilities; maintenance and storage facility; power distribution facilities; command, control, and com- munication facilities; fixed facility verification and accept- ance; infrastructure and sitework; equipment rooms and UPS spaces; guideway equipment; station equipment; main- tenance and storage facility equipment; power distribution system equipment; command, control, and communica- tions equipment; vehicles; operating system verification and acceptance; and project management and administration. • Include contingency, soft costs, and inflation/escalation to determine systems cost estimate. The total capital cost esti- mate will include factors such as contingency, escalation, and overhead and profit, in addition to soft costs that are associated with the design and construction management of the APM system. These factors are best determined and applied on a local and project-specific basis. Whether such factors are applied “above the line” or “below the line” in terms of labor and material subtotals is also best determined by the typical practices of the specific location and project. • Estimate facilities costs using quantity takeoffs. As dis- cussed in the introduction to this section, the fixed facility costs may be assigned to a conventional cost estimating entity; estimating the cost of the APM fixed facilities does not require any specialized expertise once the facilities are designed. However, it is recommended that an entity with experience in the APM industry coordinate with the cost estimator to ensure that any APM-specific issues are ade- quately addressed. • Determine system versus facilities procurement packag- ing and its impact on supplier competition. Within the APM industry, there are a variety of ways APM systems and associated fixed facilities can be procured; various methods are discussed in Chapter 10. Many procurement options exist, and the best approach should be determined by a specific procurement plan agreed to by all appropriate parties in accordance with local, state, and national law. Such a procurement plan is most appropriately developed after the planning stage of the system and is thus beyond the scope of this guidebook. However, general assump- tions regarding the procurement approach, particularly with regard to packaging different contracts, are appropriate to consider when estimating the cost of planning the APM because such packaging can affect supplier competition and price. Such factors should be considered in how the total work is packaged in terms of stand-alone contracts or con- tracts requiring a combination of construction trades. For instance, it would not be unusual to include the construction of the power distribution substation building as part of the contract that constructs the APM stations since both involve the same building trades. In addition, such packaging should be considered in conjunction with local practice and project- specific issues such as minority, women, and disadvantaged business enterprise (M/W/DBE) participation goals. Cost–Benefit Analysis At this point in the planning process, it is assumed that the proposed APM system’s level of service has been checked for 132

any fatal flaws in meeting the airport’s goals and objectives and that complete O&M and capital cost estimates have been produced for the subject system. The next recommended step is to look at those costs in terms of a cost–benefit analysis. Detailed information regarding performance of a cost–benefit analysis for an airport APM is presented in Section 9.2. • Identify a base case (no-build alternative) and an evalua- tion period over which to measure costs and benefits. The base case, no-build alternative must be evaluated over a period of time. The length of this time period should be com- mensurate with other projected time frames within which milestones affecting the airport will occur. For example, within what time frame is a particular percent increase in airport operations projected to occur? Within what time frame are a certain number of aircraft gates projected to be required? Within what time frame is a new concourse or ter- minal projected to be built? The no-build base case should be evaluated within such time frames. • Measure and compare the costs and benefits for the air- port, its passengers, and the general public if the APM is built and in the no-build base case. Some benefits that can be compared are directly related to level-of-service issues affecting the airport’s passengers and general public. Such issues may include travel time, walk distance, ease of way- finding, work effort, and comfort and/or protection from the elements. For an airside APM serving an airline hubbing operation, the benefits are more airline-focused and can translate directly into increased revenue through increased number of daily/annual flights at the airport. Refer to Sec- tion 9.2 for more details. • Evaluate the accuracy of the cost–benefit analysis and then determine whether or not the benefits outweigh the costs and the system should be built. The cost–benefit analysis will include some subjective criteria that are not as easily evaluated as objective data such as hard costs. Subjective data can be ranked, weighted, and empirically analyzed in a way that offers a fair, impartial, and accurate assessment and comparison. The parties charged with decision making should assure themselves that the cost–benefit analysis is accurate in terms of both subjective and objective data and base their ultimate build/no-build decision on this. The reader is encouraged to note Figure A-5 where the airside system has been determined to have connectivity benefits that outweigh its cost. Financial Strategies • Evaluate APM affordability. Now that the APM system planning has been approved, its overall affordability must be assessed as part of the airport’s projected capital pro- gram. This is illustrated graphically in the Figure A-6 flow- chart. At this point, several options can be considered depending on the particular financial situation of the air- port. If adequate funds exist, the entire system would likely move forward toward procurement and implementation. Another option would be to phase in the implementation of the system in order to extend cash flow requirements. Note that this approach, although not uncommon, results in cost deferment, not cost savings, and the final cost for full system implementation is invariably greater due to infla- tion factors. • Investigate financing strategies. Different financing strate- gies are airport-specific and depend upon a variety of factors, including whether the airport is functionally a department of its host city or is controlled by an independ- ent quasi-governmental body. This and other differences play a role in how the particular airport’s rates, fees, and charges are assessed and managed. The following are exam- ples of some of the more common funding avenues for air- side APM systems although they may not apply to the particular airport at hand. – Airport bonds. Such bonds may be joint revenue bonds where debt service is shared widely among all airport stakeholders. In addition, airports may issue special facil- ity bonds where the debt service is assigned to a single entity, such as an airline, or a small pool of users. Special facility bonds are typically used to fund dedicated-use projects where the project’s use is virtually exclusive to the bond guarantor. – FAA Airport Improvement Program. The AIP is a federal grant program with funding generally pro- vided via two categories: entitlement funds and dis- cretionary funds. Either of these funding types must meet certain prerequisite requirements (grant assur- ances) established by the FAA. Eligible projects are those that enhance safety, security, or capacity or mit- igate environmental concerns. Ineligible projects are those related to the airport’s operations, including maintenance. An APM system’s capital cost would typ- ically qualify for this funding type, whereas the sys- tem’s O&M costs would not be eligible.  Passenger facility charges. Most major U.S. airports collect a PFC, which is a fee added to the cost of the ticket for each enplaning passenger. The amount per ticket can vary, at the airport’s discretion, and has increased from a maximum of $3.00 per ticket when Congress approved PFCs in 1992 to a current maxi- mum of $4.50 per enplaning passenger. PFCs fall under the jurisdiction of the FAA and, similar to AIP funding, must be used for projects that enhance safety, secu- rity, or capacity, reduce noise, or increase competition between air carriers. 133

 Airport-generated revenues. Assuming such rev- enue is specifically self-generated by the airport, this funding typically has the fewest restrictions of the funding examples presented. Airports have multiple self-generated revenue streams, the largest of which being landing fees, concession and other lease agree- ments, and parking fees. Other airport-generated revenue may be tied to the specific development opportunities of the particular airport. For example, DFW International Airport was able to generate a substantial revenue stream by negotiating on-airport drilling rights with natural gas drilling companies. 134 Source: Lea+Elliott, Inc. Figure A-6. Final APM planning process.

The reader is encouraged to note the final decision diamond and process boxes in the Figure A-6 flowchart where the planning for the theoretical airside system has been completed with the sys- tem moving into the procurement and detailed design phases. Of particular note is the fact that once a specific APM technology is selected, it is often necessary to revisit and refine some of the plan- ning decisions. At the end of this appendix, a number of underground, air- side APM alignments are provided as examples of the type of sys- tem that has emerged from the APM planning process described above. For specific details on these existing airside APMs, please see Appendix B. Example 2: Planning a Landside Shuttle APM System For this discussion, refer to the Figure A-7 flowchart, Sum- mary Landside APM Planning Process. This discussion follows this summary flowchart and the subsequent, more-detailed flowcharts; italicized notes provide cues for the reader to refer to specific aspects of the flowcharts. For Example 2, the first more-detailed flowchart (Fig- ure A-8) commences with stating the principal need: “Air- port wants to improve landside mobility by providing access to parking and regional rail via an APM.” As discussed briefly in Example 1 for the airside APM system, there are different reasons justifying the implementation of a landside APM sys- tem than there are for justifying an airside APM system. This is because, over time, the airport’s physical facilities can grow to a point where the physical distances between connecting gates become too great to be traversed by means other than an APM or the physical location of connecting gates may virtu- ally dictate an airside APM system. For landside systems, no such thresholds typically exist that are as compelling for the implementation of an APM. Instead, landside APM systems are more commonly justified by: 1. Level-of-service issues in accessing remote airport facilities. Such facilities may be inherently remote (such as remote employee parking) or may have been moved from the central terminal area (CTA) to a remote location (such as a remote consolidated rental car facility) in order to free the CTA location for a higher and better use. 2. Service to multiple facilities. The benefit of a landside APM increases as the number of facilities that it serves increases. The type of facilities served by the landside APM may be symbiotic in their similar functions or may be stand-alone facilities. Regardless, a landside APM can serve as a consol- idating factor, strengthening the viability of all such facili- ties by physically linking them together. The assumptions for this appendix state that an APM has already been selected over alternate systems, but a further assumption of Example 2 is that the landside APM system inherently has a significantly higher level of service than alter- nate systems such as a busing system, although it may have an appropriately lower level of service than the Example 1 airside APM system. Operational Considerations A prerequisite for the successful planning of a landside APM is to embrace the presumption to plan the system around project-specific operational considerations and not to plan the system around a specific APM technology and its characteris- tics. The following discussion amplifies the operational consid- erations listed in the process blocks of the flowchart. System Level of Service • Determine the level-of-service priorities based on the air- port’s goals and objectives. One may initially assume that all APM systems should strive to be designed to offer the highest level of service possible. However, this is not neces- sarily the case with landside systems. For example, compar- atively longer headways may be acceptable and appropriate for a landside APM system than for an airside system. This is because a landside system typically lacks the critical time windows that must be met by an airside system. While an inbound landside passenger may have to catch a plane, the passenger’s arrival time and lead times at the airport are self- determined, not pre-determined by the airline, as are the air- side passengers’ connection times. Although some landside systems are must-ride systems in terms of distances or lack of a pedestrian right-of-way, they are typically easier to pro- vide a temporary backup system (such as buses) for than are the airside must-ride systems. Thus, a landside system’s redundancy and failure management modes may not be as critical as those of an airside system. Other landside level of service planning criteria include: • Passenger density and crowding. Landside passengers that have landed at their destination airport will choose to stop boarding a train when their perception is that the train is full. Thus, although it is not possible to purposely plan to crowd passengers onto a train, certain planning parameters can result in different levels of density and crowding on the sta- tion platform. As such, it should be decided what amount will be acceptable from a planning standpoint. The options for landside systems may be somewhat less stringent than for airside systems serving connecting airline passengers. • Passenger effort, including level changes and walk dis- tance. A generally accepted planning assumption is that fewer level changes are desirable because level changes not only increase passenger effort (even with escalators) but 135

Level-of-Service Decision-Making Flow Key: Process Data Output Start/ End Planning Process Decision-Making Flow APM Benefits Alignment Stations Guideway/ROW Capital Costs Operations & Maintenance Costs Cost–Benefit Analysis Financial Strategies Power Distribution Command, Control, and Communications Ridership System Capacity NEED System Level of Service Evaluate System Level of Service Evaluate System Level-of-Service Measures Environmental Final Design Procurement Defined APM System Functions Served Service Req’ts. Maintenance Facility Walk & Time Thresholds Source: Lea+Elliott, Inc. Figure A-7. Summary landside APM planning process.

also decrease wayfinding clarity. A generally accepted plan- ning assumption is that less walk distance is desirable. This is equally true for both landside and airside APM systems. In the United States, walk distance is defined as the distance the passenger actually walks, not the distance the passenger travels (while standing on moving walkways for example). Outside the United States, planners sometimes assume that passengers walk on moving walkways. • Ride comfort, including lateral forces and acceleration/ deceleration. Such forces are typically specified in terms of allowable maximums set by pre-established industry stan- dards. These standards exist not only for comfort but also for safety. However, exceptions may be made in certain cases. For example, when particular guideway alignment options dictate a vertical grade beyond normal practices, certain ride comfort factors will be degraded. • Passenger wayfinding, ease of use, and system simplicity. A generally accepted planning assumption is that simplicity in wayfinding is desirable. Specifically, minimizing the num- ber of decision points that the passenger must make is desir- able. All APM systems require audio and visual (signage) cues because they typically require self-use by the passenger, without attendants. Alignment • Determine station locations and area constraints. Plan- ning for the number, spacing, and placement of landside 137 Source: Lea+Elliott, Inc. Figure A-8. APM operations planning process.

APM stations should strive to provide the maximum con- venient service to the largest range of users with the fewest possible number of stations. Planning for the fewest prac- tical number of stations needed to provide the appropriate level of service helps the economy and efficiency of the sys- tem in terms of fleet size and reduces the capital and O&M costs of both the APM system and the associated fixed facil- ities. However, from a planning standpoint, if the landside system is being retrofitted to serve existing facilities, station locations may essentially be predetermined by the location of such facilities. • Create alternative alignments to connect stations. The actual guideway alignment is a means to an end. The end is to serve the stations that have been located to meet vari- ous project-specific parameters. The most efficient guide- way alignment is one that is perfectly straight and perfectly level, but in real-world planning it is seldom possible to provide such a guideway, particularly when introducing an APM into an existing airport’s landside environment. However, there is typically an optimal geometrical guide- way alignment to connect the planned stations, and the most effective way to determine such an alignment is to explore many different ones. • Evaluate alignments in terms of level of service, potential cost, and efficiency to determine preferred alignment. Using the different alternate alignments that have been developed, consider how the level of service, cost, and system efficiency are affected by the specific differences in the alternatives. These differences may include aerial ver- sus subgrade and/or combinations of aerial and subgrade alignments. Aerial alignments are typical for landside APMs. Additional areas for evaluation include the alignment’s impact on existing facilities, impact on future growth poten- tial, ease of expandability, and the ease and/or possibility of phased implementation and/or expansion. Specifics regarding the configuration of the alignment should also be evaluated, particularly for associated cost implications. • Determine preferred guideway configuration (shuttle, pinched loop, etc.) based on level of service and cost. In par- allel with the exploration of various guideway alignments, various configurations of the guideway should also be devel- oped at a conceptual level. For instance, a two-way loop configuration may provide the needed level of service, but further exploration may reveal that a pinched-loop configu- ration provides an equal level of service yet gains an eco- nomic advantage by not needing the construction of as long a guideway. While the length of landside APM systems varies greatly, for the shorter systems connecting the main terminal to a single garage or rental car facilities, the system length and system frequency requirements may be such that a dual-lane shuttle with just two trains operating (one on each lane) is sufficient to meet the capacity needs of the system. • Allow for potential propulsion technologies (cable, self- propelled). Some aspects of a guideway’s alignment have differing effects on different propulsion technologies. For instance, LIM propulsion is typically more sensitive to grades. Also, certain cable technologies are more sensitive to vertical curves (particularly concave, or sagging, vertical curves) because the cable may lift from the sheaves in certain instances. More detailed design analysis is required to con- firm and/or solve such specifics, but the planner should be aware of such issues even in the early planning stages of the APM. As noted in the guideway configuration paragraph above, the resulting dual-lane shuttle could accommodate either a cable- or a self-propelled technology. For the pur- poses of this example (and to differentiate from Example 1) it is assumed that a cable-propelled technology would ultimately be selected. Good planning practice ensures that both cable- and self-propelled technologies can be accom- modated to provide maximum supplier competition and the best price and value for the airport. The reader is encouraged to note the decision diamond in Figure A-9 where the theoretical landside system has now been planned as an elevated, cable-propelled dual-lane shuttle with 0.5 miles of dual-lane guideway and three center platform sta- tions. The APM will connect the terminal, passenger and employee parking, rental car facilities, and an intermodal/commercial devel- opment area. The decisions reached for this theoretical example (elevated, cable, shuttle, etc.) are common decisions found in actual landside APM systems. Specific decisions at each airport depend upon the site-specific environment. Reasons for the deci- sions in our theoretical example might be as follows: • Elevated–Landside APMs are in a more cost-sensitive environ- ment competing against buses on an existing roadway system (compared to an airside APM), and therefore underground construction is ruled out. At-grade systems are also difficult to fit in to an existing airport landside environment, and therefore an elevated structure is typically chosen. • Cable and shuttle—As stated above, landside APMs are ele- vated in a cost-sensitive environment. They are often shorter systems, accommodated by cable-propulsion and dual-lane shuttle operations, and provide the necessary level-of-service performance as opposed to longer systems that would cost more and require self-propelled/pinched-loop systems. Ridership • Determine appropriate design year (activity level, MAP). The landside APM should be planned for implementation at a time when ridership demand warrants it, and this thresh- old may be tied to the airport’s overall master plan and activ- ity level projections in terms of MAP or other projected levels 138

139 Source: Lea+Elliott, Inc. Figure A-9. APM capacity planning process.

of passenger activity or facility implementation. Specific future projects, such as a planned landside hotel, a consol- idated rental car facility, a light rail intermodal station, or other landside projects may trigger when an APM is warranted. • Apply factors to determine the demand on the design day. Ultimately, the ridership demand analysis for a landside sys- tem must determine how many people need to go where and when. Many of the factors such as walk speeds, distances, flow capacities, and vertical circulation capacities are the same as for airside systems. However, such factors may vary more for landside systems because the served facilities and passenger population groups are typically more diverse than for airside systems, which primarily serve passengers mak- ing online connections. • Apply hourly surge factors. Surge factors represent a case where a landside system may have more variation than an airside system. Surge factors account for a particular surge of riders above the average ridership that must be planned for and accommodated by the system. For airside systems, surges are typically a result of hub airline complexes (times that a large number of aircraft arrive, passengers transfer between aircraft, and when the aircraft depart). Surge fac- tors for a landside system may be generated by a greater vari- ety of causes and thus have greater variation over different time intervals. Surge factors for landside systems are typi- cally more project specific than for airside systems, and as such, require more research and analysis. • Account for airport access mode share, passenger arrival patterns, and airport and airline employees. These factors constitute inputs for spreadsheets or simulation programs necessary to determine the landside ridership demands. These factors are more variable for landside systems than airside systems and require expert project-specific research and analysis. This is inherently due to the wide range of types of facilities and functions that can be served by a land- side APM. For instance, a landside system planned for a coastal airport may have airport–seaport transfers as a primary ridership component, whereas an inland landside system would not have this ridership component at all. • Use spreadsheets or simulation software to determine the bidirectional surged hourly flow rates between each station for each hour of the design day. This is a specialized task that involves calculating the ridership volumes between each sta- tion, the number of passengers deboarding and boarding at each station, and the system’s peak link. As noted, in addition to the design hour of the design day, ridership is typically analyzed and determined for a variety of off-peak hours in order to accurately estimate how the APM system will oper- ate throughout a typical 24-hour period. • Determine average passenger area requirements (bag- gage). This varies by project, particularly between air- side and landside systems. Passenger area requirements are expressed as an area for each standing and seated passenger, respectively. In the case of the theoretical landside system, it is assumed that passengers will be in possession of all of their baggage (carry-on as well as checked), and the space per passenger should be calculated accordingly. Such space is typically more than for an airside system, which must accommodate only carry-on baggage. Airports typically col- lect baggage characteristics of their passengers through on- airport surveys, which can be used for the APM analysis. The reader is encouraged to note the decision diamond in Figure A-9 where the theoretical landside system has now been planned for particular surged hourly flow rates between stations for each hour of the design day with a known number of deboard- ings and boardings at each station and 5 square feet per person allocated within the vehicles. Capacity Analysis • Determine generic APM technology. The actual technol- ogy of an actual APM supplier is not assumed for this step. Rather, the planner should determine/develop a generic APM technology that is generally representative of several actual APM suppliers. This will help ensure healthy compe- tition among multiple suppliers may ultimately provide a system in accordance with the performance specifications to be developed during the subsequent design phase. An exam- ple involving this generic APM technology would be the assumption of using a generic 40-foot vehicle because many APM suppliers produce a vehicle close to a 40-foot length. • Simulate train performance over alignment to determine RTT. This typically requires the use of specialized com- puter modeling in all but the most simply configured APM systems and again should best be assigned to an entity with experience in this specialized field. • Determine vehicle capacity using average passenger space requirements. In this planning task, the generic 40-foot vehicles can be assumed to accommodate a cer- tain number of standing and seated passengers based upon the planned 5 square feet per passenger for the theoretical landside system. • Calculate the minimum headway (headway  1⁄2 of round trip time for typical shuttle). This calculation is self explanatory and considerably simpler than for the airside system in Example 1 because the theoretical landside system is being planned as a dual-lane shuttle with two trains oper- ating in a synchronized manner. However, in real world planning, landside systems may be planned for a variety of configurations, not only a dual-lane shuttle. As such, a train performance model should be utilized. This should be done by a party with experience in this type of simulation. 140

• Determine range of capacities for range of train consists. For this planning task, a variety of APM performance cri- teria must be considered jointly in order to ensure that the most efficient system is developed, just as in Example 1 for the airside system. However, in the case of this dual-lane shuttle landside system, train consist becomes primarily related to future expansion needs. This is because the dual- lane shuttle system is limited to two trains—one per lane— and future capacity expansion can only be achieved by adding vehicles to these two trains. • Compare ridership demand to capacity range and deter- mine appropriate peak-period capacity. This task deter- mines the peak link during the peak period of demand. The peak link is defined as the link between stations that has the highest ridership demand. Although other links between sta- tions will have less ridership demand, it is the single peak link that drives system capacity. • Size APM operating fleet over the entire design day (peak, off-peak, night). Because ridership demand varies over the day, the capacity of the APM system should be adjusted to match demand to the greatest degree that is possible. With the landside dual-lane shuttle, such options are limited to running either one or both trains, as well as to possible on- call operational modes. Typically, with a dual-lane shuttle, both trains are operational during peak hours. During off- peak night hours, only one train is operated, which allows maintenance on the non-operating train as well as wayside maintenance of the inactive guideway lane. Such down- times are typically rotated each night between the two trains and their guideways. An on-call mode may be used during off-peak hours where the single operational train idles in a berthing position at one of the stations until it is called into service via passenger-sensing motion detectors in the stations or by passenger use of elevator style call buttons in the stations. The reader is encouraged to note the decision diamond in Figure A-9 where the theoretical landside system has now been planned for a six-vehicle fleet consisting of two three-car trains with 40-foot vehicles resulting in 120-foot train lengths running at 3.6 minute peak headways resulting in a capacity of 2,500 pphpd. Technical Considerations The successful planning of an APM also involves consider- ation of technical aspects of the system. Each APM system is proprietary and is therefore unique with regard to many par- ticular technical aspects. The challenge to the APM planner is to appropriately plan the system in accordance with known technical considerations, yet not to a degree so specific that certain suppliers are unable to provide a viable system. This increases competition, which is in the best interests of the air- port. The following discussion amplifies the technical consid- erations listed in the process blocks of Figure A-10. Power Distribution • AC or DC propulsion power distribution? Although the actual onboard traction motors that propel APM vehicles are universally AC, the propulsion power distribution system that provides the guideway power to the vehicles along the guideway may be AC or DC, depending upon the particular supplier. While there are advantages and disadvantages to each, from a planning perspective it is not useful to assume one is better than the other or to attempt to predict which will be used. Rather, it is important for the planner to understand the differences between the distribution systems that affect the planning of the system. For instance, power distribution substations for a DC system can be located further apart than those of an AC system. More and larger equipment within the substation is required for DC systems. Thus, substation space requirements will be greater for DC systems. DC ground current is of greater concern than that of AC and may require corrosion control measures and current testing facil- ities that are not required for AC systems. For the landside system in this example, cable propulsion has been chosen. For planning purposes, all cable systems can be assumed to use AC power to the drive machines that move the rope (cable) that ultimately moves the trains. The trains of a cable- propelled system are passive in terms of propulsion power, but do have onboard housekeeping electrical requirements for lighting, HVAC, and communications. Thus, there is power distribution along the guideway of a cable system, albeit not propulsion power; this power is also AC. • Determine system power demand based on headways and train consists over the course of the design day. The sys- tem’s power demand will be used in O&M budgetary plan- ning by the airport and will also be needed by the local utility company, which will provide the high-side power to the APM system. The power demand may be manually derived for small systems, but computer modeling of power demand is virtually essential for larger systems with multiple trains and changing train consists. • Based on system power demand, determine the location, size, and number of power distribution substations. This is where some of the differences in planning for an AC or a DC system will come into play. However, regardless of AC or DC power distribution, some general planning rules are applicable. Generally, the substations should be located directly adjacent to the guideway if possible. If multiple substations are required, their general locations should be located equidistantly along the guideway, and equidistant from each other to the degree possible, in order to mini- mize voltage drops and increase efficiency. Each substation 141

142 Source: Lea+Elliott, Inc. Figure A-10. APM technical planning process.

will require access for equipment and personnel, including on-site parking and loading areas. Housekeeping power to the substations must also be planned. For the subject land- side APM system, cable propulsion has been assumed, and thus planning for power distribution is somewhat simplified compared to an airside system as there is no need for multi- ple power distribution stations located along the wayside of the guideway. Instead, all propulsion power equipment is typically located in a single facility adjacent to the cable drive equipment. • Coordinate design and construction of the power distri- bution system with the local utility company. This task involves coordinating the layout of the physical aspects of the power distribution system. For instance, the local utility company may provide and install the power service entrance or what is sometimes referred to as the distribution yard. In addition, other design aspects of the distribution system must be coordinated with the local utility company. For instance, regenerative braking enhances energy efficiency by capturing braking energy and feeding it back to other trains or back to the utility. However, some utility companies will not allow this. AC systems are more likely to induce harmonic noise on the utility distribution lines. This may require harmonic filtering, and this should also be coordi- nated with the utility company. The reader is encouraged to note the decision diamond in Fig- ure A-10 where the landside system in this example has now been planned for two 480 VAC drive motors, with one motor powering each guideway lane individually. Maintenance and Storage Facility Analysis • Determine size of facility based on space requirements for maintenance bays, enclosed workshops, administration areas, and personnel areas. For shuttle systems such as the landside system in this example, the MSF is typically online because the trains are never removed from the main guide- ways for maintenance. For larger pinched-loop systems, the MSF is offline, as described in Example 1. Although the MSF houses a specialized function, architectural and engi- neering firms require no specialized expertise to design and produce the construction documents for the MSF once it is programmed. However, it is this architectural program- ming that is critical to the success of the MSF. • Determine maintenance facility location (online or offline) based on fleet size and system length. Online maintenance facilities are typically located directly beneath a station if the system employs an aerial guideway, or directly adjacent to a station if the system is below grade. This is due primarily to architectural and functional efficiency. However, some exist- ing shuttle systems have an online MSF located between sta- tions, and from a planning perspective, the exact location for an online MSF is best determined in consideration of project-specific parameters. APM maintenance facilities are unlike a bus maintenance facility in that they are clean and quiet because internal combustion engines are not involved. Thus, from a planning perspective, the MSF may be located in sensitive areas, such as within an airport termi- nal building, without any negative impact. • Provide a route for delivery of materials to the facility. This includes site access that can accommodate trucked deliver- ies, including full-size tractor-trailers on occasion. A route for material delivery applies not only to the siting of the MSF but to circulation within the facility itself. Planning should dimensionally accommodate a forklift with pallets in and around all maintenance bays, including a path to parts stor- age or other accessed areas. Planning should accommodate delivery and storage of items that dimensionally will not fit within a freight elevator. One example is replacement power and signal rail, which typically comes in 40-foot lengths. The reader is encouraged to note the decision diamond in Fig- ure A-10 where the theoretical landside system has now been planned to include a 15,000 square foot online maintenance facil- ity located underground at the end (parking) station. The guide- way mainlanes will serve as test tracks when needed. Command, Control, and Communications Analysis • Determine the space and equipment requirements of the central control facility. The size and layout of the CCF varies somewhat in proportion to the size of the APM sys- tem. However, all CCFs have basic requirements that must be planned for. These include the control console with sys- tem mimic screens, and CCTV monitors for station (and possibly other) surveillance, all within sight of the central control operators. Typically, an APM equipment room is located directly adjacent to the CCF. The specific require- ments for the equipment and layout of the facility must be considered to ensure that an adequate spatial foot- print is reserved in the planning stage. The CCF should be planned to accommodate additional equipment and/or personnel required for future expansion of the system, if such expansion is anticipated. With regard specifically to the land- side system in this example, such CCF expansion consider- ations are probably not applicable because a cable-propelled dual-lane shuttle is difficult to expand in an economical or practical way. Such expansion is not impossible, but if it is an important planning consideration, a self-propelled dual-lane shuttle would be a better planning choice. • Determine the location of the facility. From a planning perspective, combining the CCF with the MSF (locating the CCF within the MSF) is typically a solution that allows 143

functional consolidation and efficiencies. If the CCF is located remotely from the MSF, some duplication of mini- mum essential facilities such as restrooms and administra- tive space may be required. The initial location planned for the CCF should be considered its permanent location, and any possible expansion or changes to adjacent or surround- ing facilities that could cause disruption to the CCF should be considered when choosing this location. Although CCFs have been successfully relocated, the CCF is the electronic center of the APM system; thus, such relocations are diffi- cult, expensive, and invariably cause significant operational disruptions. • Determine staff requirements for central control opera- tors. Adequate staffing and the number of CCOs should be considered with project-specific requirements. As a general planning rule, a minimum of two CCOs should staff the CCF at any time. The total number of CCOs will depend upon sys- tem size, shift arrangements, and benefit (particularly leave) factors. The reader is encouraged to note the decision diamond in Fig- ure A-10 where the theoretical landside system has now been planned to include a 2,000 square foot CCF located within the airport operations center with a single redundant workstation and a minimum of a single CCO on duty. Station and Passenger Flow Analysis A prerequisite note regarding the following bullets is that architectural analysis and programming is critical to the suc- cessful planning of the stations. Also, reference Section 8.4, Stations, for additional detailed discussion regarding the pro- gramming of APM stations. • Determine minimum platform length using maximum train consist length. Various queuing areas for passengers must be taken into account when the total platform length is determined. These include queues for the trains as well as for escalators and elevators. If future expansion plans call for increasing the number of vehicles per train, then the platform must be sized to accommodate this future train length. In these cases, the automatic station doors for the future vehicles are typically not installed, although their positions are reserved by removable window wall assem- blies or some type of removable panels. In some instances, the future automatic station door sets may be procured and installed prior to their actual activation. • Define desired level of service in terms of passenger queue area and circulation area on the center platform. This level of service can range from planning for virtually no waiting queue to, in rare occasions, missed trains being an acceptable situation during peak periods. The queue area depends upon the headways of the trains to a large degree, and thus should be planned in conjunction with the trains’ performance parameters. The circulation on an APM platform requires circulation paths to and from the trains and to and from vertical circulation elements. Few if any other functions typically exist on the platform. For instance, it is not recommended to install seating, vending machines, newspaper racks, telephone banks, FIDS, or other such amenities on an APM platform. The short wait times on the platform do not permit use of such amenities without interfering with the primary purpose of the platform, which is to quickly and efficiently move people on and off the trains. • Determine minimum platform width based on vertical circulation requirements and desired level of service dur- ing peak demand. This is another topic for which the reader is encouraged to review Section 8.4, Stations, for additional detailed discussion. As an overview, the minimum platform width for small APM systems (i.e., a short landside shuttle) may likely be determined by the minimum width required for the vertical circulation elements. Assuming all of these elements would be grouped at one end of the station, their combined dimensions would constitute the minimum pos- sible width of the associated platform. Also, the type of station is a key factor in determining minimum platform width(s). For example, a center platform station has a single area that must accommodate two functional platforms for trains arriving on either side. This single platform accom- modates both boarding and deboarding passengers, and the fact that two trains may arrive at the same time (for exam- ple, at the middle station of a three-station shuttle) must be considered. Side platform stations have platforms that accommodate only one train each, but each platform must have a full complement of vertical circulation elements and must accommodate both boarding and deboarding pas- sengers. A triple platform station (also referred to as a “side- center-side” or “flow-through” station platform) has three separate platforms, each with a full complement of verti- cal circulation elements. In this case, the center platform serves as a boarding platform only and the two side plat- forms serve only as deboarding platforms. The automatic door sets for the deboarding platforms open several seconds before the door sets for the boarding platform. This estab- lishes the proper queue movement and allows the fastest and most efficient boarding and deboarding of the train, although this station type is the most expensive and requires the most overall space. • Determine NFPA 130 compliance. An excellent guide for life safety issues is the National Fire Protection Association’s “NFPA 130—Standard for Fixed Guideway Transit and Pas- senger Rail Stations.” Its content is well researched and is dedicated to specialized life safety issues. For example, the NFPA 130 test for emergency egress from a station is not a 144

typical/historical building code occupancy type analysis, but rather an analysis of time, distance, and pedestrian move- ment that most accurately reflects the real-world situation on the station platform. The reader is encouraged to review Section 8.4, Stations, for additional detailed discussion on this topic. • Develop and evaluate alternative station configurations and vertical circulation locations to determine the pre- ferred station layout and size. The guidelines given in this appendix and in Section 8.4, Stations, provide only an over- view of basic APM station design parameters. An architect, in collaboration with an APM specialist, should fully explore different station configurations within the context of project- specific and site-specific factors in order to develop the most appropriate specific station design(s). The reader is encouraged to note the decision diamond in Fig- ure A-10 where the landside shuttle system of this example has now been planned to utilize center platforms approximately 120’ long, with one elevator, one open stair (in addition to any required fire exits/stairs), and two pairs of escalators. Cost Considerations A variety of costs must be considered for the successful plan- ning of an APM system. These costs include the initial capital costs required to implement the APM as well as the ongoing operations and maintenance costs of the system. In terms of APM planning, a cost–benefit analysis is recommended as a test of the overall viability of the APM system. This section focuses primarily on APM system costs and not the costs of the associated fixed facilities. This is because the costs associated with the APM system’s fixed facilities can be estimated by a professional estimating firm. The APM system costs, on the other hand, vary widely within the APM industry because each different APM supplier uses a different and proprietary tech- nology. Costs for different projects by the same supplier may also vary significantly because of different scales of economy involving fleet size, capacity requirements, level of bid compe- tition, and so forth. Thus, estimating and comparing the cost of a proposed APM system against standard industry costs is difficult because repeatable and consistent costs within the industry are quite elusive. The following discussion amplifies the cost considerations listed in the process blocks of Figure A-11 and offers relevant points to be considered in preparing system cost estimates. Capital Costs • Gather detailed historical data on systems costs of simi- lar airport APM implementations. A key consideration is to ensure, to the greatest degree possible, the similar nature of the APM systems for which the capital cost data is being gathered. Since no two APM systems are identical, it is best to select a set of systems as similar to each other as possible and then adjust the capital costs according to the known differences from the system being compared. • Adjust historical data for airport-specific factors. These factors can include the likelihood of union or open-shop labor and the associated local labor rates by category for appropriate building or highway labor categories. Other airport-specific and location-specific factors include local and national material costs and/or availability, local infla- tion and unemployment rates, and specific bonding require- ments and the associated costs of procuring such bonds. • Estimate the cost of each subsystem or element of the APM system based on normalized historical data. Breaking the estimated costs down by system and major subsystem facili- tates the comparison, possible negotiation, and reconcilia- tion of estimated costs with the proposed actual costs. Within the APM industry, there are fairly standardized breakdowns for both system estimates and the supplier’s proposed costs. Although the total scope of these breakdowns is beyond the scope of this guidebook, the following are some major, industry-accepted breakdown categories: guideway facilities; station facilities; maintenance and storage facility; power distribution facilities; command, control, and communica- tion facilities; fixed facility verification and acceptance; infra- structure and sitework; equipment rooms and UPS spaces; guideway equipment; station equipment; maintenance and storage facility equipment; power distribution system equip- ment; command, control, and communications equipment; vehicles; operating system verification and acceptance; and project management and administration. • Include contingency, soft costs, and inflation/escalation to determine systems cost estimate. The total capital cost estimate will include factors such as contingency, escala- tion, and overhead and profit, in addition to soft costs that are associated with the design and construction manage- ment of the APM system. These factors are best deter- mined and applied on a local and project-specific basis. Whether such factors are applied “above the line” or “below the line” in terms of labor and material subtotals is also best determined by the typical practices of the specific loca- tion and project. • Estimate facilities costs using quantity takeoffs. As dis- cussed in the introduction to this section, the fixed facility costs may be assigned to a conventional cost estimating entity; estimating the cost of the APM fixed facilities does not require any specialized expertise once the facilities are designed. However, it is recommended that an entity with experience in the APM industry coordinate with the cost estimator to ensure that any APM-specific issues are ade- quately addressed. 145

146 Source: Lea+Elliott, Inc. Figure A-11. APM cost–benefit planning process.

• Determine system versus facilities procurement packag- ing and its impact on supplier competition. Within the APM industry, there are a variety of ways APM systems and associated fixed facilities can be procured; various methods are discussed in Chapter 10. Many procurement options exist, and the best approach should be determined by a spe- cific procurement plan agreed to by all appropriate parties in accordance with local, state, and national law. Such a procurement plan is most appropriately developed after the planning stage of the system and is thus beyond the scope of this guidebook. However, general assumptions regard- ing the procurement approach, particularly with regard to packaging different contracts, are appropriate to consider when estimating the cost of the APM because such packag- ing can affect supplier competition and price. For example, for a small APM system, small suppliers may not have expe- rience in, or even be capable of, proposing on a full DBOM approach to system implementation. Such factors should be considered in how the total work is packaged in terms of stand-alone contracts or contracts requiring a combination of construction trades. In addition, such packaging should be considered in conjunction with local practice and project- specific issues such as M/W/DBE participation goals. Operations and Maintenance Costs • Gather historical data on APM operations costs at simi- lar airport applications. A key consideration is to ensure, to the greatest degree possible, the similar nature of the APM systems for which the data is being gathered in terms of all operational and technical parameters. Since no two APM systems are identical, it is best to select a set of sys- tems as similar to each other as possible and then adjust the O&M costs according to the known differences from the system being compared. • Adjust historical data for airport-specific factors. These factors can include the likelihood of union or open-shop labor and the associated local labor rates by category. Other airport-specific factors include the party that is intended to perform the O&M services, both initially and in the future. Options could include the initial supplier, a possible third party provider by way of competitive bids, or the airport’s own in-house staff. • Determine annual fleet mileage and fleet size based on operating fleet over the design day (see capacity analysis). Factors considered in the capacity analysis must also be considered in determining the fleet mileage, which deter- mines the wear and tear on the vehicle fleet, which in turn determines the frequencies of major and minor mainte- nance intervals. • Derive energy, consumables, and parts consumption from the annual fleet mileage and historical data. Some addi- tional options for the airport to consider are how and where particular O&M costs will be accommodated and budgeted for. For example, parts and consumables might be included in the annual budget for an airport’s maintenance depart- ment, whereas the electrical costs for system operations might be included in the annual budget of an airport’s util- ity department. • Derive staffing and management requirements based on fleet size, mileage, and historical data. Staffing for the APM system will consist of several different categories, and staffing will vary in proportion to system size and complexity. There are typically three work shifts that provide 24 hour coverage of the system 365 days per year. “First Shift” typically refers to the shift most closely approximating 8 a.m. to 5 p.m. “Third Shift” typically refers to the overnight shift when the system is operating off-peak and wayside and other mainte- nance tasks are best accomplished. “Second Shift” typically encompasses the 8 hours between first and third shifts. Staff categories typically consist of administrative and man- agement staff, operations staff, and maintenance staff. The administrative staff typically includes a site manager and secretary or other clerical positions. Administrative staff typically works first shift. Operations staff typically includes the central control operators as well as mechanics and mechanics’ helpers. Operations staff must cover all three shifts. Maintenance staff typically includes electrical tech- nicians, mechanical technicians, and their helpers. Mainte- nance staff typically focuses their work during the third shift although there is typically overlap between operations and maintenance staff members and the shifts that they work. • Include contingency and other factors to determine the O&M cost estimate. The total O&M cost estimate will include factors such as contingency, escalation, overhead, and profit, and these factors are best determined and applied on a local and project-specific basis. Whether such factors are applied “above the line” or “below the line” in terms of labor and material subtotals is also best determined by the typical practices of the specific location and project. Cost–Benefit Analysis At this point in the planning process, it is assumed that the proposed APM system’s level of service has been checked for any fatal flaws in meeting the airport’s goals and objectives and that complete O&M and capital cost estimates have been pro- duced for the subject system. The next recommended step is to look at those costs in terms of a cost–benefit analysis. Detailed information regarding performance of a cost–benefit analysis for an airport APM is presented in Section 9.2. • Identify a base case (no-build alternative) and an evalua- tion period over which to measure costs and benefits. The 147

base case, no-build alternative must be evaluated over a period of time. The length of this time period should be commensurate with other projected time frames within which milestones affecting the airport will occur. For exam- ple, within what time frame is a particular percent increase in airport operations projected to occur? Within what time frame are a certain number of landside parking spaces pro- jected to be required? Within what time frame is a new remote consolidated rental car facility or on-airport hotel projected to be built? The no-build base case should be evaluated within such time frames. • Measure and compare the costs and benefits for the airport, its passengers, and the general public if the APM is built and in the no-build base case. Some benefits that can be compared are directly related to level-of-service issues affect- ing the airport’s passengers and general public. Such issues may include travel time, walk distance, ease of wayfinding, work effort, and comfort and/or protection from the ele- ments. Refer to Section 9.2 for more details. For landside APM systems, costs should be considered in terms of lost potential revenue as well as expenditures. For example, if the level of service provided by a landside APM would help moti- vate a four-star hotel chain to build a remote, yet on-airport, landside hotel, what is the lost revenue potential to the air- port should the hotel and/or other transit-oriented develop- ment (TOD) not be built due to the lack of an APM? • Evaluate the accuracy of the cost–benefit analysis and then determine whether or not the benefits outweigh the costs and the system should be built. The cost–benefit analysis will include some subjective criteria that are not as easily evaluated as objective data such as hard costs. Subjective data can be ranked, weighted, and empirically analyzed in a way that offers a fair, impartial, and accurate assessment and comparison. The parties appropriately charged with deci- sion making should assure themselves that the cost–benefit analysis is accurate in terms of both subjective and objective data and base their ultimate build/no-build decision on this. The reader is encouraged to note Figure A-11 where the land- side system has been determined to have connectivity benefits that outweigh its cost. Financial Strategies • Evaluate APM affordability. Now that the APM system planning has been approved, its overall affordability must be assessed as part of the airport’s projected capital pro- gram. This is illustrated graphically in the Figure A-12 flowchart. At this point, several options can be considered, depending upon the particular financial situation of the airport. If adequate funds exist, the entire system would likely move forward toward procurement and implemen- tation. Another option would be to phase in the imple- mentation of the system in order to extend cash flow requirements. Note that this approach, although not uncommon, results in cost deferment, not cost savings, and the final cost for full system implementation is invari- ably greater due to inflation factors. • Investigate financing strategies. Different financing strate- gies are airport-specific and depend upon a variety of factors, including whether the airport is functionally a department of its host city or is controlled by an inde- pendent quasi-governmental body. This difference and others play a role in how the particular airport’s rates, fees, and charges are assessed and managed. The following are examples of some of the more common funding avenues for landside APM systems although they may not apply to the particular airport at hand. – Airport Bonds. Such bonds may be joint revenue bonds where debt service is shared widely among all air- port stakeholders. In addition, airports may issue spe- cial facility bonds where the debt service is assigned to a single entity, such as an airline, or a small pool of users. Special facility bonds are typically used to fund dedi- cated-use projects whereby the project’s use is virtually exclusive to the bond guarantor. – Public–private partnerships. A public–private partner- ship (sometimes referred to as PPP or P3) is a contrac- tual agreement between a public-sector agency and a private-sector business venture where the parties com- bine their skills and assets to build and operate a public- use facility. Each sector (public and private) also shares in the risks and rewards associated with the project. Although P3s have been used to provide public services, most involve physical facilities. Of these public-use facil- ities, civil and structural infrastructure (roadways, bridges) are most common, but transit projects are not unusual. The specifics of the contractual agreement between the parties are crafted in accordance with the particulars of the political and statutory environment, the project itself, and a host of other factors. Such agree- ments are complex and the option of P3 financing is best explored with an entity of proven experience in this field. – Landside commercial developments. If a main purpose of the landside APM is to serve landside commercial development, funding for the APM could be pursued as part of such development, or if the commercial develop- ment is by an entity totally independent from the airport, funding by that entity could be pursued. The percentage of the total funding by the entities separate from the air- port would likely depend upon the proportional levels of service provided by the APM. If the APM links commer- cial development to a regional rail system (with an inter- modal station at the airport’s main terminal), then the 148

149 Source: Lea+Elliott, Inc. Figure A-12. Final APM planning process.

rental revenue potential of the development may be increased due to the improved regional access, as well as through potential density/height increases to the devel- opment via zoning waivers tied to the transit access. – Airport-generated revenues. Assuming such revenue is specifically self-generated by the airport, this funding typically has few use restrictions. Airports have multiple self-generated revenue streams, the largest of which come from landing fees, concession and other lease agreements, and parking fees. Other airport-generated revenue may be tied to the specific development oppor- tunities of the particular airport. For example, DFW International Airport was able to generate a substantial revenue stream by negotiating on-airport drilling rights with natural gas drilling companies. – Customer facility charges. An example of a CFC is where the airport, in accordance with a joint use agreement with its airlines, rental car companies and/or other tenants, assesses dedicated fees to fund particular projects or facil- ities. In recent years, this example has been commonly applied to fund both the construction and operation of consolidated rental car facilities. Typically, the customer actually sees the CFC listed on the receipt for the car rental. If the landside APM serves the rental car facility, its costs (total or partial) could be included in the CFC. Note that in these examples, the charge is made via the rental car company and not directly by the airport (as park- ing fees are, for example), and the fee is not exclusively for the APM system. A precedent regarding airport APMs is that their ridership is free of charge, primarily because riding an APM in an airport environment is typically perceived as being necessary or required to reach a certain destination. Although this may be less true for a landside system as opposed to an airside system, and although vir- tually no other form of public transit is free, the public’s perceived entitlement to riding free on a landside APM will likely remain. CFCs have not typically been assessed directly by airport authorities exclusively for funding APM systems, but nothing precludes this other than lack of prece- dent and the public relations hurdle of overcoming the pas- senger’s perceived entitlement to riding free. The reader is encouraged to note the final decision diamond and process boxes in Figure A-12 where the planning for the theoretical landside system has been completed with the system moving into the procurement and detailed design phases. Of particular note is the fact that once a specific APM technology is selected, it is often necessary to revisit and refine some of the planning phase decisions. At the end of this appendix, a number of underground, airside APM alignments are provided as exam- ples of the type of system that has emerged from the APM plan- ning process described above. For specific details on these existing airside APMs, please see Appendix B. Resulting Systems Table A-1 summarizes the relevant characteristics of the airside and landside APM systems resulting from the theo- retical planning process for Examples 1 and 2. Because of the proprietary nature of APM systems and project-specific requirements for each APM system, the table is not meant to describe the precise design characteristics of the subject systems. Such specifics are typically defined by the APM supplier during the design-build process. The purposes of the planning process for an APM are to confirm the viabil- ity of the APM system and if viable, to identify characteris- tics and costs of the APM system to a degree that will allow the airport to: 1. Develop the procurement documents for use in procuring the APM and, 2. Confirm and provide proper and adequate funding for the APM. Further explanation of points (1) and (2) are as follows: The planning process results in parameters for the pro- curement documents, which include system performance specifications. Performance specifications are commonly used in the APM industry, as opposed to a standard Con- struction Specification Institute specification, which is typically used for conventional construction projects. In simplest terms, an APM performance specification tells the APM supplier what to design but not exactly how to design it. For example, Figure A-4 shows that the planning process resulted in three-car trains using 40-foot vehicles for the pinched-loop airside system. This may be accurate for most APM suppliers proposing on the theoretical system, but a particular supplier may propose four-car trains using 30-foot vehicles if that were the supplier’s proprietary vehi- cle. Assuming all other performance characteristics and spec- ifications are met, this alternate train configuration would be acceptable. The planning process results in parameters accurate enough for developing the planning-level estimates of the APM system’s initial capital costs as well as an estimate of the ongoing O&M costs. Although, as in the foregoing exam- ple of three-car versus four-car trains, it is not possible to know with complete certainty if all the planning parameters will be met exactly as anticipated in the final design of the APM system, such potential differences are typically dis- counted for purposes of estimating. This is based on expe- rience that indicates that the aspect of competition between suppliers is an overriding factor in their proposal pricing, compared to such differences between the proprietary aspects of their systems. 150

151 Example 1 Example 2 Airside – Service to three terminal stations, one at each of three freestanding terminals – HUB a irport Landside – Service to one terminal station, an intermodal facility and/or parking structure. Guideway Length (dual - lane miles) 1.5 0.5 Alignment Underground, p inched - l oop Elevated, d ual - l ane s huttle System Capacity 6,000 2,500 No. of Vehicles (Total Fleet) 24 6 Capacity/ Car 1 75 50 Cars/Train 1 3 3 Area/Passenger 3 . 3 ft 2 5 ft 2 No. of Trains 8 2 Peak Hour Headway 2.3 minutes 3.6 minutes Propulsion Power r ail 600 VAC Cable 480 VAC cable drive motors No. of Power Substations 3 to 4 1 Maintenance Facility Off line Online – under an end station Ready/Receiving/Test Track 0 .2 miles of ready/receiving track Guideway serves as test track Central Control Facility location & staff CCF located within MSF – three CCOs on duty CCF located within airport operations center – one CCO on duty Number of Stations 3 2 to 3 Station Platform Type Side - c enter - s ide Center Vertical Circulation One elevator, one stair, and two single - direction escalators for each of the three platforms at each station One elevator, one stair, and two pairs of escalators per station 1Single APM car or vehicle is the typical 40-foot-long car offered by many suppliers. Source: Lea+Elliott, Inc. Table A-1. Characteristics of relevant APM systems.

152 Atlanta – Airside • Seven stations, 1.1 miles of guideway • Underground, pinched loop • Four vehicles per train, with 1.8-minute headway • Fleet size of 49 vehicles with 10,000 pphpd Denver – Airside • Four stations, 1.2 miles of guideway • Underground, pinched loop • Four vehicles per train, with 2.0-minute headway • Fleet size of 31 vehicles with 8,300 pphpd Washington Dulles – Airside • Four stations, 1.4 miles of guideway • Underground, pinched loop • Three vehicles per train, with 1.9-minute headway • Fleet size of 29 vehicles with 7,105 pphpd APM APM APM

153 Atlanta – Landside • Three stations, 1.4 miles of guideway • Elevated, pinched loop • Two vehicles per train, with 2.0-minute headway • Fleet size of 12 vehicles with 2,700 pphpd Birmingham (U.K.) – Landside • Two stations, 0.4 miles of guideway • Elevated, shuttle • Two vehicles per train, with 2.0-minute headway • Fleet size of four vehicles with 1,608 pphpd London Gatwick – Landside • Two stations, 0.7 miles of guideway • Elevated, shuttle • Three vehicles per train, with 2.6-minute headway • Fleet size of six vehicles with 4,200 pphpd APM APM APM

Next: Appendix B - Inventory of Airport APM Systems »
Guidebook for Planning and Implementing Automated People Mover Systems at Airports Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB’s Airport Cooperative Research Program (ACRP) Report 37: Guidebook for Planning and Implementing Automated People Mover Systems at Airports includes guidance for planning and developing automated people mover (APM) systems at airports. The guidance in the report encompasses the planning and decision-making process, alternative system infrastructure and technologies, evaluation techniques and strategies, operation and maintenance requirements, coordination and procurement requirements, and other planning and development issues.

The guidebook includes an interactive CD that contains a database of detailed characteristics of the 44 existing APM systems. The CD is also available for download from TRB’s website as an ISO image. Links to the ISO image and instructions for burning a CD-ROM from an ISO image are provided below.

Help on Burning an .ISO CD-ROM Image

Download the .ISO CD-ROM Image

In March 2012, TRB released ACRP Report 37A: Guidebook for Measuring Performance of Automated People Mover Systems at Airports as a companion to ACRP Report 37. ACRP Report 37A is designed to help measure the performance of automated people mover (APM) systems at airports.

In June 2012, TRB released ACRP Report 67: Airport Passenger Conveyance Systems Planning Guidebook that offers guidance on the planning and implementation of passenger conveyance systems at airports.

(Warning: This is a large file that may take some time to download using a high-speed connection.)

Disclaimer: The CD-ROM is offered as is, without warranty or promise of support of any kind either expressed or implied. Under no circumstance will the National Academy of Sciences or the Transportation Research Board (collectively “TRB’) be liable for any loss or damage caused by the installation or operation of this product. TRB makes no representation or warranty of any kind, expressed or implied, in fact or in law, including without limitation, the warranty of merchantability or the warranty of fitness for a particular purpose, and shall not in any case be liable for any consequential or special damages.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!