Urban sprawl

Urban sprawl (also known as suburban sprawl or urban encroachment) is defined as "the rapid expansion of the geographic extent of cities and towns, often characterized by low-density residential housing, single-use zoning, and increased reliance on the private automobile for transportation". Urban sprawl has been described as the unrestricted spread over large expanses of land around an urban area of housing, commercial development, and roads, with little concern for very dense urban planning.

Urban sprawl refers to a special form of urbanization, and it relates to the social and environmental consequences associated with such development. In modern times some suburban areas described as "sprawl" have less detached housing and higher density than the nearby core city. Medieval suburbs suffered from the loss of protection of city walls, before the advent of industrial warfare. Sometimes the urban areas described as the most "sprawling" are the most densely populated.

The modern disadvantages and costs of urban sprawl include increased travel time, transport costs, pollution, and destruction of the countryside. The revenue for building and maintaining urban infrastructure in these areas are gained mostly through property and sales taxes. Most jobs in the US are now located in suburbs generating much of the revenue.

In Europe, the term peri-urbanisation is often used to denote similar dynamics and phenomena, but the term urban sprawl is currently being used by the European Environment Agency.