Public capital is the aggregate body of government-owned assets that are used as a means for productivity. Such assets span a wide range including: large components such as highways, airports, roads, transit systems, and railways; local, municipal components such as public education, public hospitals, police and fire protection, prisons, and courts; and critical components including water and sewer systems, public electric and gas utilities, and telecommunications. Often, public capital is defined as government outlay, in terms of money, and as physical stock, in terms of infrastructure. Current state in the U.S. In 1988, the U.S. infrastructure system including all public and private non-residential capital stock was valued at $7 trillion, an immense portfolio to operate and manage. And according to the Congressional Budget Office, in 2004 the U.S. invested $400 billion in infrastructure capital across federal, state, and local levels including the private sectors on transportation networks, schools, highways, water systems, energy, and telecommunications services. While public spending on infrastructure grew by 1.7% annually between 1956 and 2004, it has remained constant as a share of GDP since early 1980s. Despite the value and investment of public capital, growing delays in air and surface transportation, aging electric grid, an untapped renewable energy sector, and inadequate school facilities all have justified additional funding in public capital investment. The American Society of Civil Engineers have continued to give low marks, averaging a D grade, for the nation's infrastructure since its inception of the Report Card in 1998. In 2009, each category of infrastructure varied from C+ to D− grades with an estimated $2.2 trillion of needed public capital investment. The aviation sector remains mired in continued delays in the reauthorization of federal programs and an outdated air traffic control system. One in four rural bridges and one in three urban bridges are structurally deficient. States are understaffed and underfunded to conduct safety inspections of dams. Texas alone has only seven engineers and an annual budget of $435,000 to oversee more than 7,400 dams. Electricity demand outpaces energy supply transmission and generation. Almost half of the water locks maintained by the U.S. Army Corps of Engineers are functionally obsolete. Drinking water faces an annual shortfall of $11 billion to manage their aging facilities and comply with federal regulations. Leaking pipes lose an estimated of clean drinking water a day. Under tight budgets, national, state, and local parks suffer neglect. Without adequate funding, rail