Infrastructure is the set of interconnected structural elements that provide the framework for supporting the entire structure. The term is often used very abstractly. For instance, software engineering tools are sometimes described as part of the infrastructure of a development shop, and the term infrastructural capital in economics may be overly broad, as it includes a range from clothing to a continent-spanning canal system. This term can overlap with the notion of internal improvements and public works (see American System (economics)).

Definition disputes

In national security, the term "critical infrastructure" is also extremely broad (although it should be less inclusive as not all infrastructure should be considered critical) and includes support, e.g. for banking, and other such processes of questionable merit. One issue is the necessity of means of protection, and of accounting, in increasing value of life. Advocates of a broad definition usually argue that without these "critical" systems, the rest of the infrastructure is looted, burned, or not safe to use.

Another issue is whether means of persuasion, like computer or radio or television technology, can qualify as infrastructure in any sense, as it is more belief-sustaining than life-sustaining. The arguments parallel those for means of protection, with conservatives generally asserting that belief in a common view of reality, especially in emergency response, is critical to survival.

Urban planning usage

The term is used most often in an urban planning context to denote the facilities that support specific land uses and built environment. This article focuses on those, to avoid the more political issues above.

Typically, infrastructure in this context denotes two general groups of support systems: transportation modalities (roads, rail, etc.) and utilities. These typically compose both public and private systems, and some ambiguously held in common.

Infrastructure may also refer to necessary municipal services, whether provided by the government or by private companies. If provided by nature, e.g. the flow of a river, they are called nature's services and are distincted (at least in economics) as the product of natural capital. This may be augmented or directed by infrastructural capital, e.g. a dam or canal or irrigation ditch. In general what is called infrastructure tends to be very embedded in the natural landscape and cannot be moved from place to place. Even municipal services rely necessarily on fixed locations, e.g. fire stations in central positions in a city, transmission towers on tall buildings, etc..

Infrastructure (in the civic sense) includes:

• Transportation
  • Roads
  • Highways
  • Railroads
  • Public transport
  • Airports
  • Health systems
  • River freight
  • Bike paths
  • Sidewalks
• Utilities
  • Electricity
  • Natural gas
  • Coal delivery
  • Water supply
  • Sewers
  • Telephone service
  • Radio and television bandwidth allocation
  • Cable service
• Municipal services
  • Trash collection
  • Police protection
  • Fire protection
  • Flood protection
  • Postal system
  • Minting and backing currency

• "Soft Infrastructure" is a term that denotes institutions that maintain the health and cultural standards of the population. Principally, this refers to
  • Public education
  • Public health systems including public hospitals