Guidebook for Measuring Performance of Automated People Mover Systems at Airports (2012)

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.

50 This guidebook has been provided to identify a set of performance measures and associated data requirements for airport APM operators to assess and improve performance, compare airport APM systems, and plan and design future systems. The measures are intended to address the efficiency, effectiveness, and quality of APM systems at airports. Thus far, the guidebook has set forth the measures to be used in comparing airport APM systems (i.e., external measures). These measures can also be used to assess and improve the performance of an individual airport APM system and, therefore, can be used as internal measures as well. However, there are other internal measures that may be useful for assess­ ing and improving the performance of an individual airport APM system that do not work as well as external measures. The following sections discuss these additional internal mea­ sures as well as those to be used in the planning and design of airport APM systems. 6.1 Internal Measures for Assessing and Improving Performance of Airport APM Systems Airport APM systems have varying characteristics and are made up of different technologies that can make it challenging to develop meaningful measures that are directly comparable among airport APM systems. Chapter 5 set forth the measures that may be the best in achieving such comparisons. How­ ever, there are many other performance measures that can be implemented by airport APM systems and that may be worth­ while to track for assessing and improving the internal perfor­ mance of an individual airport APM system even though they may not be worthwhile for comparisons among systems. Some of the internal measures currently in use or that could be implemented at airport APM systems are: • Average vehicle service miles per collector shoe; • Average vehicle service miles per traction motor; • Average vehicle service miles per running tire; • Average vehicle service miles per guidance tire; • Average cycles per drive cable (for cable­propulsion APMs); • MTBF or MTTR, ATC system: – MTBF or MTTR, automatic train operation (ATO) sub­ system; – MTBF or MTTR, ATS subsystem; – MTBF or MTTR, ATP subsystem; – MTBF or MTTR, traction power distribution system; and – MTBF or MTTR, guideway equipment system. The purpose of this chapter is not to provide a compre­ hensive list or detailed definition and requirements for these measures; rather it is to illustrate that the number and type of performance measures that could be implemented for inter­ nal measurement purposes are quite extensive. Although operators of an airport APM system may choose to implement numerous performance measures, an effective performance measurement program should reflect a balanced set of a few vital measures (see Section 4.2). More often than not, airport APM system owners/operators implement these few vital measures to represent performance of the entire system, but individual departments within the O&M organi­ zation will often track many other measures directly related and helpful to their discipline. Sometimes this involves the temporary establishment of a performance measure due to an abnormally high failure rate of a particular component that may not have otherwise been the target for such a mea­ sure. For example, the vehicle maintenance department may be interested in understanding the wear rate of running tires so as to compare one manufacturer to another, or in un­ derstanding why there are higher wear rates at a given time (e.g., there could be a track condition causing this higher wear). Or, there may be a component on an electronic circuit board failing in relatively large numbers after operating without incident for a number of years. In this case, implementing a performance measure associated with this component would C h a p t e r 6 Other Airport APM System Performance Measures

51 be expected for a certain period until the cause is identified and rectified, but it would likely be a measure that would not have otherwise been implemented nor permanently instituted had the spike in failures not have occurred. 6.2 Measures for Planning and Designing Airport APM Systems APMs play a critical role in transporting passengers effi­ ciently and safely at airports and therefore need to be highly dependable and safe. The measures that can be used for plan­ ning and designing airport APM systems largely include the availability­, reliability­, and maintainability­type measures similar to those discussed in previous sections of the guidebook. For example, during the planning and design phases of an airport APM system, APM system suppliers determine the dependability, availability, reliability, and/or maintainability values of subcomponents, equipment, and subsystems, based on certain anticipated failure rates, to verify that the overall sys­ tem will meet the target of the particular performance measure once service is established. Often, these targets are stringent due to the critical role APM systems play at airports. When planning APMs, such high performance standards can be considered in developing alignments and configurations that will allow APM system suppliers to provide the equipment and equipment redundancies necessary to ensure that the system will perform at these levels. For example, there could be several crossovers in an airport APM system that allow APM vehicles to operate around a failed section of track and still move passen­ gers among airport facilities fairly efficiently. The consideration of crossover quantities and placement during the planning and design phases of an airport APM system is driven, in part, by satisfying the high targets set for these service availability performance measures. Similarly, certain airport APM systems have the capabil­ ity to automatically couple APM vehicles into larger train consists and immediately insert these trains into service to rapidly respond to either increased demand in the system or to degraded operational modes brought on by one or more mainline failures. This automated coupling feature, along with the crossover quantity/placement issue mentioned previously, can allow a system to be rapidly reconfigured and maintain the same line capacity in a degraded operational mode as in nominal operational modes. The consideration of this feature in the planning and design phases of an airport APM is again driven, in part, by satisfying the high targets set for the avail­ ability performance measures. Safety is also extensively considered in the planning and design of airport APM systems, and performance measures are used to quantify and verify during the design phase that hazards are limited to essentially negligible levels. For example, the mean time between hazard element (MTBHE) performance measure is used, in part, to verify and validate that the duration of time between hazard elements for the ATC system meets or exceeds the required level. Other measures that can be considered during the planning and design of an airport APM system include the walk distance to airport APM stations, number of level changes to and from the APM station, the APM platform size and configuration [i.e., center platform, side platforms, triple (flow­through) platforms, etc.], ultimate design line capacity of the system, travel time, and passenger vehicle space allocations. These are discussed in ACRP Report 37: Guidebook for Planning and Implementing Automated People Mover Systems at Airports.