The National Mall in Washington, D.C., encompasses some of our country's most treasured icons and serves as a public gathering place for millions of visitors each year. The National Air and Space Museum, for example, was the most visited museum worldwide in 2003, hosting 9.4 million visitors. Federal agencies with facilities on the National Mall have begun implementing physical security enhancements to protect their facilities and the visiting public. This report responds to Congressional interest in the efforts and expenditures pertaining to these security enhancements and discusses (1) the physical security enhancements that have been implemented on the National Mall since September 11, 2001, the additional enhancements planned, and the costs of these enhancements; (2) the considerations given to incorporating access and aesthetics into the design and approval of these security enhancements, and how issues of access and aesthetics are perceived by visitors in relation to these enhancements; and (3) examples of how federal agencies are using key practices to implement the enhancements, and any challenges the agencies are experiencing in using these key practices. In commenting on a draft of this report, the Smithsonian Institution, Department of the Interior, Department of Agriculture, and National Gallery of Art provided clarifying and technical comments, which were incorporated into this report where appropriate.

Since September 11, 2001, federal agencies on the National Mall have obligated about $132 million for physical security enhancements, with the National Park Service and the Smithsonian accounting for about 75 percent of the total obligations. Security enhancements include additional security personnel, facility upgrades, and equipment and technology. Planned enhancements include the installation of permanent security barriers to protect against vehicle bombs. Public access and aesthetic considerations are integral to the design and approval of security enhancements on the National Mall. Federal agencies must coordinate with reviewing organizations, such as the National Capital Planning Commission, and consider aesthetics, historic preservation, urban design, urban planning, and environmental effects when implementing security enhancements. Although federal agencies reported that the review process can be time-consuming, review organizations noted that early and frequent consultation with them helps to ensure a smoother, more efficient, and expeditious review process. GAO's survey of about 300 visitors to the National Mall, and reports from federal agencies, indicate that visitors value access to and the appearance of the National Mall and generally find the current level of security enhancements acceptable. GAO's survey results also suggest that visitors regard access and aesthetics as important priorities when adding security enhancements to the National Mall. Federal agencies on the National Mall reported using five of the six key practices identified by GAO--allocating resources using risk management, leveraging technology, information-sharing and coordination, performance management and testing, and strategic management of human capital--in implementing physical security enhancements. However, none of the federal agencies on the National Mall reported using the key practice of aligning assets to mission in implementing security measures because they believe they do not have excess or underutilized facilities or consider the practice applicable to property under their jurisdiction. Agencies identified balancing ongoing mission priorities with the need for security as a common challenge in using key practices to implement physical security enhancements.