Mixed-use development is — in a broad sense — any urban, suburban or village development, or even a single building, that blends a combination of residential, commercial, cultural, institutional, or industrial uses, where those functions are physically and functionally integrated, and that provides pedestrian connections. The term ("a mixed-use development") may also be used more specifically to refer to a mixed-use real estate development project — a building, complex of buildings, or district of a town or city that is developed for mixed-use by a private developer, (quasi-)governmental agency, or a combination thereof.
Traditionally, human settlements have developed in mixed-use patterns. However, with industrialisation as well as the invention of the skyscraper, governmental zoning regulations were introduced to separate different functions, such as manufacturing, from residential areas. In the United States, the heyday of separate-use zoning in the U.S. was after World War II, but since the 1990s, mixed-use zoning has once again become desirable as the benefits are recognized. These benefits include:
Throughout most of human history, the majority of human settlements developed as mixed-use environments. Walking was the primary way that people and goods were moved about, sometimes assisted by animals such as horses or cattle. Most people dwelt in buildings that were places of work as well as domestic life, and made things or sold things from their own homes. Most buildings were not divided into discrete functions on a room by room basis, and most neighborhoods contained a diversity of uses, even if some districts developed a predominance of certain uses, such as metalworkers, or textiles or footwear due to the socio-economic benefits of propinquity. People lived at very high densities because the amount of space required for daily living and movement between different activities was determined by walkability and the scale of the human body. This was particularly true in cities, and the ground floor of buildings was often devoted to some sort of commercial or productive use, with living space upstairs.
This historical mixed-used pattern of development declined during industrialisation in favor of large-scale separation of manufacturing and residences in single-function buildings. This period saw massive migrations of people from rural areas to cities drawn by work in factories and the associated businesses and bureaucracies that grew up around them. These influxes of new workers needed to be accommodated and many new urban districts arose at this time with domestic housing being their primary function. Thus began a separating out of land uses that previously had occurred in the same spaces. Furthermore, many factories produced substantial pollution of various kinds. Distance was required to minimize adverse impacts from noise, dirt, noxious fumes and dangerous substances. Even so, at this time, most industrialized cities were of a size that allowed people to walk between the different areas of the city.
These factors were important in the push for Euclidian or single-use zoning premised on the compartmentalization of land uses into like functions and their spatial separation. In Europe, advocates of the Garden City Movement were attempting to think through these issues and propose improved ways to plan cities based on zoning areas of land so that conflicts between land uses would be minimized. Modernist architects such as Le Corbusier advocated radical rethinking of the way cities were designed based on similar ideas, proposing plans for Paris such as the Plan Voisin, Ville Contemporaine and Ville Radieuse that involved demolishing the entire center of the city and replacing it with towers in a park-like setting, with industry carefully sited away from other uses.