Planopedia

Mixed-use development incorporates two or more uses into the same building, or in the same general area. The term often refers to development that combines residential functions with commercial or even industrial ones, but can also encompass cultural and institutional uses as well as public amenities. Mixed-use development is typically characterized as walkable and pedestrian-friendly, offering residents more chances to live, work, and shop in a single neighborhood and reduce their dependence on car travel. 

The term "mixed-use development" can refer to either the general practice of combining multiple uses, or to a specific development project that does so. Projects with ground-floor retail and upper-floor residences are only one type of mixed-use development. These mixed-use projects combine multiple uses into a single building, often placing more public uses (like retail) at or close to ground level, with more private uses (like housing or offices) higher up. Other mixed-use projects include multiple single-use buildings within the same site or zoning parcel. Still others might combine both types of mixed-use development (sometimes referred to as "vertical" and "horizontal" mixed-use, respectively) into a single walkable area.

Mixed-use development has been a common feature of urban places throughout history, though it wasn't always referred to as such. During the 20th century, concern over factors like overcrowding and pollution led U.S. planners and municipal leaders to situate housing well away from commerce and industry, a history that dovetails with intentional racial segregation in the name of fighting "slums" or "blight." The widespread adoption of automobile transportation and the rise of the modern suburb facilitated the transition to single-family zoning, which many housing advocates argue creates exclusionary neighborhoods out of reach for lower-income households.

In more recent decades, many planners have reconsidered the merits of mixed-use development. For instance, mixed-use neighborhoods tend to be denser and more walkable than neighborhoods reserved for single uses, with many potential positive effects on environmental sustainability and public health. Mixing uses can also ease access to transit and amenities, reduce vehicular traffic, and facilitate greater human connection. Per acre, mixed-use development is often more tax-efficient than single-use development. Infrastructure that serves mixed-use development can also be better consolidated and less costly.

Coupled with rising demand, the relative rarity of mixed-use neighborhoods in U.S. cities limits their affordability. Other drawbacks might involve quality of life issues like noise or heavy foot traffic. Finally, mixing uses doesn't guarantee a well-integrated neighborhood. A downtown high-rise might mix several uses and remain wholly cut off from the life of the street.

Implementing mixed-use development can be a challenge. Zoning codes and other local statutes often segregate uses, requiring mixed-use developments to acquire variances and other site-specific approvals. Opposition from local stakeholders, often referred to as NIMBYs, can also arise. In some cases, developers must share costs to upgrade local infrastructure and municipal service provision. Financing can also be a difficult prospect, since each use must be evaluated separately. On the other hand, combining multiple uses into a single project diversifies financial risk.