Mixed-use development refers to the practice of containing more than one type of use in a building or set of buildings. In zoning terms, this can mean some combination of residential, commercial, industrial, office, institutional, or other uses.
History
Mixed-used development was the most prominent style of development during the large majority of the history of human cities and towns. Because people walked for daily transportation, it was most convenient to locate the uses in proximity. People often made a living from their own homes. This was particularly true in cities, where the bottom floor was often devoted to some sort of commercial use, and living space was upstairs.
Mixed-used development fell out of favor during the Industrial Age in favor of more efficient manufacturing in dedicated structures. Many of these buildings produced substantial industrial pollution, detrimental to those who lived nearby. These factors were important in the push for Euclidian zoning that separated land uses.
Another impetus for Euclidian zoning was the birth of the skyscraper. Fear of buildings blocking out the sun led many to call for zoning regulations, particularly in New York City. Zoning regulations, first put into place in 1916, not only called for limits on building heights, but eventually called for separations of uses. This was largely meant to keep people from living next to polluted industrial areas. This separation however, was extended to commercial uses as well, setting the stage for the suburban style of life that is common in America today. This type of zoning was widely adopted by municipal zoning codes.
Benefits
Throughout the late 20th century, it began to become apparent to many urban planners and other professionals that mixed-use development had many benefits and should be promoted again. As American cities deindustrialized, the need to separate residences from dangerous factories became less important. Completely separate zoning created isolated "islands" of each type of development. In many cases, the automobile became a requirement for transportation between vast fields of residentially zoned housing and the separate commercial and office strips. Jane Jacobs' influential The Death and Life of Great American Cities argues that a mixture of uses is vital and necessary for a healthy urban area.
Zoning laws attempt to address these problems by using mixed-use zoning. A mixed use district will most commonly be the "downtown" of the community. The mixed use guidelines often result in residential buildings with streetfront commercial space. Retailers have the assurance that they will always have customers living right above and around them, while residents have the benefit of being able to walk a mere number of yards to get groceries and household items, or see a movie.
Drawbacks
Mixed use development is seen as too risky by many developers and lending institutions because economic success requires that the many different uses all remain in business. Most development throughout the mid to late 20th century was single-use, so many development and finance professionals see this as the safer and more acceptable means to provide construction and earn a profit. Christopher B. Leinberger notes that there are 19 standard real estate product types that can obtain easy financing through real estate investment trusts. Each type, such as the office park and the strip mall, is designed for low density, single use construction. Another issue is that short term discounted cash flow has become the standard way to measure the success of income-producing development, resulting in "disposible" suburban designs that make money in the short run but are not as successful in the mid to long term as walkable, mixed use projects. "Good urban architecture costs upward of 50 percent more than typical suburban buildings. In urban areas, residents and businesses demand a higher quality of building, since you are walking past them, not driving by at 45 miles an hour with the buildings set back 150 feet," Leinberger explains.
Mixed use commercial space is often seen as being best suited for retail and small office uses. This precludes its widespread adoption as the trend to ever-larger corporate and government employment accelerates.
Mixed use residential space is best suited to those who prefer public amenities to private, regulated personal space. The lack of private outdoor space for kids and pets is anathema to some, particularly in some North American cultures.
Construction costs for mixed-use development currently exceed those for similar sized, single-use buildings[citation needed]. Challenges include fire separations, sound attentuation, ventilation, and egress. Additional costs arise from meeting the design needs: In some designs, the large, high-ceilinged, columnless lower floor for commercial uses may not be entirely compatible with the smaller scale of walled residential space above. Often the parking space requirements for businesses exceed those of residential development. Thus, mixed use projects often require a large number of parking spaces that may be difficult to finance. It should be noted however that in mixed-use developments in some denser areas, owning an automobile might be considered a luxury rather than a neccesity.
Others maintain that modern consumers prefer big box retailers, as evidenced by the fact that most grocery shoppers today would prefer the convenience of weekly shopping, as opposed to picking up each day's food items from many small shops.