Human-Centered Systems
Civil Infrastructure

Patrick McCarthy
Purdue University

Webster's New 20^th Century Dictionary defines system as a "regularly interacting or interdependent group of items forming a unified whole." There are many obvious examples that share the defining characteristic of regular interdependency/interaction, including economic systems, political systems, environmental systems, ecological systems, and urban systems. Simple or complex machines also encompass this concept of a system. In each of these instances one could identify the relevant actors, agents, or parts that regularly interact to form the unified whole. Further, by the above definition, each of these systems could be segmented into a set of distinct but related sub-systems. An urban system, for example, itself is comprised of political, economic, social, environmental, etc. sub-systems.

However one defines the term "important", human-centered systems are those in which individuals play an important interactive role. Individuals do not passively react to systemic changes but take an active role that not only determines the system's current state but also how that system dynamically evolves and interacts with other systems over time. In other words, individuals manage the system to suit their collective present and expected future needs. This raises a number of important questions and issues on how best to manage the system.

Historically, political, economic, and a variety of other forces have induced individuals to congregate and form urban communities or systems. A natural requirement of such systems is the development of civil infrastructure, a sub-structure or "underlying foundation" that supports the political, economic, work, recreational, residential, and other of a community's varied activities. Among a community's civil infrastructure are its transportation networks (highway, rail, air, and water), water supply facilities, sanitary and storm sewers, communication capabilities, educational and medical facilities, libraries, and parks. Civil infrastructure capital assets, similar to private capital, have two important characteristics: they are long-lived; and they require periodic maintenance. The long life span of most civil infrastructure implies that a community has an age distributed set of assets at any given point in time. Some civil infrastructure may be a few years old but much, and probably most, of these public sector assets will be many years if not decades old. In addition to expending resources to increase their stock of infrastructure, communities must devote part of their local resources to ensuring that these assets continue to provide reliable services that meet required standards of operation.

Through scientific discovery and innovation in the sciences, technological developments have had significant impacts upon communities' abilities to strengthen their infrastructure support for the citizenry. At the same time, these advances have created complex and sophisticated systems that are unwieldy at best and inefficiently maintained and used at worst. A challenging task for communities is to find ways to effectively manage this set of interacting and interdependent infrastructure. But effective management and functioning of a complex system of interrelated assets requires that relevant information on various levels be available to interested parties, including those who use the assets, those who maintain the assets, and those who make policy decisions about future capital and maintenance activities. Information currently available to asset stakeholders is not sufficient to provide detailed information on asset inventories, locations, qualities, inspection procedures and deterioration, the extent to which the asset is effectively and efficiently used and maintained, the value of existing assets, and whether future resources should be devoted to additional infrastructure capital or maintenance on existing capital. Although some communities may be able to answer some of these questions for some of their assets, no community is likely to answer all of these questions for all of their assets. Moreover, few if any communities have the ability to identify the effects that changes in one part of the infrastructure will have upon other parts of the system.

This raises a question. Do communities today have a civil infrastructure system? Possibly not. Certainly, all communities have civil infrastructure in the form of transportation, water, sewage, etc. assets but do these assets regularly interact to form a unified whole? Possibly, but probably not. And to the extent that components of civil infrastructure are systems that operate independently and are not fully integrated in an urban environment, existing civil infrastructure does not comprise a system.

By facilitating the generation, distribution, and presentation of data relevant to civil infrastructure, past and continuing advances in information technology (e.g. GIS, GPS, intranet, Internet, etc.) offer society important tools for managing their public assets. But this also implies a need to harness the information in such ways that the needed data will be accessible to end users in appropriately required detail. Essentially, the question is how do we exploit the increasing potential for generating useful information in order to satisfy what are apt to be multiple and conflicting objectives in the face of multiple, and perhaps uncertain constraints. Not only does this depend upon how technology evolves, but it will also depend upon the set of defined objectives.

Ideally, an information based human-centered civil infrastructure system would collect, combine, distribute, and productively summarize in easily accessible forms the wealth of interrelated data generated from its sub-systems. It could provide visual representations of changes to the system as well as extract relevant data for financial or statistical analyses. Changes to the system, whether they be maintenance actions, additional assets, breakdowns, unexpected flow changes, and so forth would seamlessly percolate through the rest of the system, updating associated links, and enabling civil infrastructure managers to more efficiently and effectively use the scarce infrastructure resources available. Further, one can easily imagine that evolving information technologies could imply alternative and less costly organizational arrangements for managing civil infrastructure. More decentralized organizational structures may use fewer resources as public asset managers adopt these technologies.

The challenge that I see for civil infrastructure is in creating an appropriate information-based environment that will enable civil infrastructure professionals to further integrate and more productively manage their existing and future stocks of public capital, and to do so across increasingly longer timeframes.