To determine what would be sufficient to meet the nation’s demand for infrastructure services such as efficient and safe mobility and clean water is not simple. The investment requirements depend on (1) the supply of service—what facilities exist, their condition and maintenance, how efficiently they are operated, and how services might be provided other than through capital spending—and (2) the demand for such services by the public, which can be influenced, in part by the price charged for infrastructure services and the state of the economy. Infrastructure investment estimates can vary greatly depending on the extent to which such factors are considered in investment calculations. For example, the investment required to maintain or rehabilitate existing facilities could differ significantly from the investment required to meet a specified level of service. Moreover, focusing on the provision of service, rather than the condition of a structure or facility, can lead to the consideration of less costly, noncapital alternatives to meeting the demand for infrastructure. For example, to meet a specified level of service on roads, such as keeping traffic flowing at the speed limit, decisionmakers might consider changing the timing of traffic lights rather than building new lanes. Furthermore, future investment needs are not a predetermined reality and can be affected by more efficient use of existing infrastructure. For example, technological improvements can increase the efficiency of infrastructure. In addition, pricing strategies can affect the use of infrastructure— relatively higher fees can encourage users to economize on their consumption. The seven agencies we reviewed develop information on infrastructure investment requirements because of their roles in financing and developing infrastructure. (See fig. 1.) ARC, the Army Corps, EPA, FAA, FHWA, and FTA provide funding for transportation, water supply, and wastewater treatment infrastructure that is owned, operated, and maintained by others. GSA and the Army Corps are directly responsible for acquiring and maintaining federal office buildings and dams and flood- control structures, respectively. At the request of the Congress, EPA, FAA, FHWA, and FTA periodically prepare long-term infrastructure investment estimates. Every 5 years, ARC prepares an estimate of the cost to complete the Appalachian Development Highway System, which it finances by distributing federal funds to states within Appalachia. GSA maintains information on the investment needs for public buildings and the Army Corps maintains information on the investment needs for water resources (inland and deep draft navigation, flood control, and shore protection), hydropower, water supply and wastewater treatment. The investment estimates developed by the seven agencies will be funded, at least in part, by federal financing. The Army Corps’ estimate only includes the federal portion of investment. GSA’s estimate for investment in public buildings will be financed entirely with federal funds. Figure 2 shows the spending trends from fiscal years 1990 to 1999 for the seven agencies. Spending (in constant 2000 dollars) ranges from an average of $150 million per year for ARC to an average of $20.6 billion per year for FHWA. Although these seven agencies have made large investments in public infrastructure, state and local governments and the private sector play important roles in financing significant portions of some infrastructure, such as water treatment and supply and transportation. Preparing investment estimates is a capital decisionmaking activity by federal agencies. In 1998, we identified the practices of leading government and private-sector organizations in capital decisionmaking.During that review, we found that conducting a comprehensive needs assessment is an important first step in an organization’s decisionmaking process for infrastructure because it allows an organization to (1) consider its overall mission, (2) identify the resources needed to fulfill both immediate requirements and anticipated future needs on the basis of results-oriented goals and objectives that flow from the organization’s mission, and (3) consider both capital and noncapital approaches to addressing these goals. The following leading practices relate to developing and using investment estimates: conduct a comprehensive assessment of the resources needed to meet an agency’s mission and results-oriented goals and objectives; establish a baseline inventory of existing assets, evaluate their condition, determine if they are performing as planned, and identify excess capacity; consider alternative ways to address needs, including noncapital use cost-benefit analysis as a primary method to compare alternatives and select economically justified investments; rank and select infrastructure projects for funding based on established criteria; budget infrastructure projects in useful segments; develop a long-term capital plan that defines capital asset decisions; establish procedures to review data developed by others and using independent reviews of data and methods to further enhance the quality of estimates. The leading practices we identified reflect requirements that the Congress and Office of Management and Budget (OMB) have placed on federal agencies that are aimed at improving federal agencies’ capital decisionmaking practices. These requirements relate to aspects of investment estimates, such as developing cost information, measuring the benefits of proposed investments, and using investment estimates as a first step toward acquiring infrastructure. These requirements include, for example, the Chief Financial Officers’ Act of 1990, which required the development of accounting and financial systems to report cost information and that the principles used in accounting for program costs be consistent with those used in developing program budgets. In addition, the Government Performance and Results Act of 1993 (Results Act) required agencies to develop mission statements, long-range strategic goals and objectives, and annual performance plans. The Results Act emphasized identifying and measuring outcomes, including benefits. In addition, the Congress enacted the Federal Acquisition Streamlining Act of 1994 to improve the federal acquisition process. Title V of the act was designed to foster the development of (1) measurable cost, schedule, and performance goals and (2) incentives for acquisition personnel to reach these goals. To help agencies integrate and implement these and other requirements, OMB added a section to its annual budget preparation guidance (Circular A-11) requiring agencies to provide OMB with information on major capital acquisitions and to submit a capital asset plan and justification. This guidance is supplemented by OMB’s Capital Programming Guide, which provides detailed steps on planning, budgeting, acquiring, and managing infrastructure and other capital assets. The steps in OMB’s guide include the concepts covered by our 10 leading practices. The seven agencies we reviewed produce investment estimates for water resources, hydropower, water supply, wastewater treatment, airports, highways, mass transit, and public buildings. Some estimates—for water resources, hydropower, and public buildings—are developed for federal spending; the other estimates are developed for spending from federal, state, and local sources. The estimates cannot easily be compared because they were developed using different methods, time periods, and funding sources. A fundamental reason that the estimates were prepared differently and lack comparability is that they are developed and used for different purposes. Some agencies use the information to determine the financial resources needed to manage and/or repair their own assets, and other agencies develop estimates at the request of the Congress to provide general information to decisionmakers or to help direct funding to recipients of federal assistance. The seven agencies identified investment amounts that vary from GSA’s estimate of $4.58 billion over 1 to 5 years to repair public buildings to FHWA’s estimate of $83.4 billion each year over 20 years to preserve and improve the nation’s highways. The investment estimates are summarized in table 1. The investment estimates cannot be easily compared or simply “added up” to produce a national estimate of all infrastructure investment needs because of differences in the methods used, time periods covered, and funding sources. For example, EPA used engineering-based approaches to develop costs for its drinking water and wastewater treatment estimates. By contrast, FHWA developed a computer model to forecast the future condition of and improvements to highway segments that uses cost-benefit analysis as the primary criteria for including improvements in its overall investment estimate. In addition, the estimates involve differing time periods. For example, FAA’s estimate of airport infrastructure investment covers 5 years, while ARC and the Army Corps produce estimates of undefined time periods for highways and water resource projects, respectively. Some agencies prepared their estimates in constant year dollars—ARC’s estimate is in 1995 dollars—while other agencies, such as GSA, presented their estimates in current dollars. The estimates also include differing funding sources: estimates by the Army Corps and GSA include only the costs to the federal government, while estimates by the other five agencies include total costs to federal, state, and local organizations. Each of the seven agencies used data from various localities, states, or agency regional offices and aggregated those data to produce a national estimate for infrastructure investment. Each agency’s process for developing its investment estimate is summarized below. They are described in detail in appendix II. The Army Corps estimated that $38 billion in federal funds was required to complete water resources and hydropower infrastructure projects already under construction as of March 30, 2001. Infrastructure projects included in this estimate were initially identified by local governments, groups, and/or private citizens, who requested assistance from the local Army Corps district office. According to an Army Corps official, regional Army Corps personnel evaluate the requests and determine both the seriousness of the problems and the need for immediate solutions. Project costs are estimated by engineers and other professionals using existing industry data. The agency also uses cost-benefit analysis to determine which projects are economically justified and would assist the agency in reaching its goals, such as environmental protection and flood mitigation. The evaluation and cost estimate is sent to the agency’s headquarters, and selected projects are submitted for funding as part of the Department of Defense’s annual budget. FAA estimated that $35.1 billion in federal and nonfederal funds was required for airport infrastructure from 1998 to 2002. Data for the investment estimate come primarily from airport plans—such as airport master plans and layouts--which include proposals and cost estimates for specific infrastructure projects at individual airports. FAA officials in field offices review each project, and approved projects are entered into a FAA database. FAA officials in headquarters review the database for anomalies in the data, then add up the estimated cost of each project to produce an overall investment estimate.