6.7 Infrastructure

Infrastructure is expensive to build and maintain, so it's usually paid for by governments or large utility companies. Once built, it lasts for decades and locks in patterns of development.

• Transportation: roads, highways, bridges, bus and rail transit, ports and airports.
• Water and sanitation: clean water supply, sewers and wastewater treatment.
• Energy: power plants and electrical grids.
• Communications: phone networks, fiber-optic cables and cell towers.
• Social infrastructure: schools, hospitals, parks and public safety.

Businesses locate where infrastructure lets them move goods, workers and data cheaply. Highway interchanges attract warehouses and edge cities (6.2). Ports and airports attract logistics firms. Fast internet attracts tech companies. Places with good infrastructure attract investment, which generates taxes to pay for more infrastructure, so advantages build on themselves.

Transit can open up opportunity. Bogotá, Colombia, built the TransMilenio bus rapid transit system, which opened in 2000 and gives buses their own lanes so they move like a subway at lower cost. Medellín, Colombia, added cable cars in 2004 to connect low-income hillside neighborhoods to the metro, cutting long commutes to jobs downtown.

Where infrastructure goes, and where it doesn't, can deepen inequality. In the 1950s and 1960s, U.S. interstate highways were often routed through Black and immigrant neighborhoods. In St. Paul, Minnesota, Interstate 94 cut through the Rondo neighborhood, and in New Orleans, an elevated stretch of I-10 replaced the tree-lined median of Claiborne Avenue, a center of Black business life in the Tremé neighborhood. Homes and businesses were destroyed, and the remaining areas were split and polluted.

In many fast-growing cities in lower-income countries, informal settlements lack piped water, sewers and reliable power, so residents pay more for water from vendors and face greater health risks. A digital divide also exists within cities: neighborhoods without affordable high-speed internet are cut off from online schooling, jobs and services.

Infrastructure decisions happen at several scales. A city decides where bus routes go; a national government funds highways or high-speed rail; global investors finance ports and power plants. The effects also show up at different scales, from a single block split by a highway to a whole region gaining from a new port.