Key Characteristics

Infrastructure generally shares several key characteristics: 

• Long-lived assets: They involve significant initial investment in durable, long-lasting engineered structures.
• Networked delivery: Services are typically delivered through an interconnected system designed to serve many users (e.g., power grids, road networks, water pipelines).
• High sunk costs: The investment in the delivery system is often dedicated to a specific purpose and cannot easily be converted to other uses.
• Public benefit/externalities: The systems provide broad societal benefits beyond direct users (e.g., a strong transport network benefits the entire economy).
• Natural monopolies: Often, the technology and cost structures naturally lead to a single provider being the most efficient option (e.g., one set of water pipes per street).
• Both public and private goods aspects: While usage can often be restricted by price (a private good characteristic), consumption is often non-rival up to a point of congestion (a public good characteristic). 

Types and Examples

• Transportation: Roads, bridges, railways (including tracks, signaling, and rolling stock), airports (runways, terminals), ports, and inland waterways.
• Utilities and Power: Electricity generation, transmission, and distribution networks; water supply systems, irrigation canals, and sanitation/sewerage systems.
• Communication: Telecommunication networks, telephone lines, and broadband internet infrastructure.
• Public Facilities: Schools, hospitals, and administrative buildings can also be considered part of a nation’s personal and institutional infrastructure.