Improving Zoning with UDOs, Even as Challenges Remain
Unified Development Ordinances (UDOs) are designed to provide clear and coordinated planning frameworks by combining traditional zoning and land use regulations into a single document. This consolidation aims to enhance regulatory efficiency and policy standardization to effectively meet community goals. UDOs employ form-based zoning, a tool for managing municipal growth and development that improves consistency, coordination, and standardization as a city progresses, including neighborhood appearance maintenance and other community characteristics. It’s important to note that form-based zoning can impose additional constraints on a community’s incentive and ability to provide accessible, affordable housing.
UDOs allow communities to easily see overlapping regulations and zones, which may support communities’ overall health by preventing the development of industrial and residential areas in the same vicinity. UDOs may also encourage economic segregation, a situation in which people of different income levels are concentrated in different areas. According to Howard (2016), this segregation indirectly impacts health due to the limited availability of essential services and healthier environmental conditions for the economically disadvantaged. UDOs often restrict certain types of affordable housing, including manufactured homes. This restriction could be regarded as discriminatory as low-income people often depend highly on certain types of low-cost housing. Additionally, applied research around UDOs, as it relates to larger community equity goals, is limited and does not focus on the impacts on affordable housing and/or health outcomes among minority and low-income households.
City UDO Case Studies
The following cases are examples of cities, instead of counties, that have adopted Unified Development Ordinances. In most cases, a county's UDO does not directly enhance or constrain a city's land use and development because cities typically have their own regulation and planning powers. A county's UDO applies mainly to unincorporated areas, not incorporated cities. However, there can be indirect influences, such as county-wide planning efforts or state-mandated requirements that cities must comply with. For example, in some states, counties might have comprehensive plans that cities are expected to align with, but the cities still set their own zoning rules.
Raleigh, North Carolina: Raleigh’s land use plan evolved amid rapid growth and changing urban needs. The city had long relied on an outdated code, “Part 10 Code,” and aging comprehensive plans that no longer addressed modern challenges such as suburban sprawl, disconnected street networks, and inefficient land use practices. A multi-year effort was made to replace the outdated Part 10 Code with a UDO that better reflected the city’s modern planning objectives. However, stakeholder groups had divergent views on the process and the output of the UDO adopted in 2013. City officials and Raleigh’s Planning Department were largely positive, recognizing the new ordinance as a long-overdue update that streamlined and modernized Raleigh’s regulatory framework. The development industry and homebuilders had concerns over ambiguous provisions in the code and a potential for increased administrative burdens, particularly regarding contentious issues like accessory dwelling units (ADU) and tree conservation. Public groups and neighborhood associations felt that despite opportunities for participation, their input was not sufficiently reflected in the adopted version of the UDO, leaving them with a sense of exclusion from decisions that would impact their communities.
The UDO diverged from exclusionary zoning practices, which only allow for one type of use in a specific area, and aimed to better accommodate modern urban development. It replaced the rigid use-based approach with a more flexible, context-sensitive urban form allowing building character, mixed-use development, and greater density. This change fostered more diverse and adaptable neighborhoods. It created new requirements for parking, street design, and open space, underscoring their role in creating a more pedestrian-friendly and interconnected urban fabric. It also streamlined the permitting process and reduced bureaucratic hurdles for developers. Ambiguities, such as provisions regarding accessory dwelling units (ADU) and tree conservation, still remain that could challenge consistent implementation of Raleigh’s UDO.
Buffalo, New York: Buffalo adopted a UDO in 2016 called the “Green Code”. It was part of the city’s effort to replace its old zoning regulations. Buffalo leadership promoted the UDO as an urban vision for the city, meant to simplify land use regulations, attract development, reverse population decline and suburban sprawl, and increase access to affordable housing. The Green Code influenced the removal of minimum parking requirements, which was intended to incentivize more market-responsive, affordable development. This resulted in increased lots that were located in high-walkability and multimodal travel areas. It also enhanced developers’ ability to construct on smaller lots, increased projects’ financial viability, and promoted construction on underutilized, existing developed land. However, the UDO failed to effectively integrate vacant lots, and did not solve the shortage of affordable housing.
Denver, Colorado: Denver integrated form-based codes, which prioritize design and form over specific land use, into its UDO adopted in 2010. This reflected the city’s shift toward design-focused urban planning. The new code was reported to have the potential to create some development difficulties because it did not clearly spell out how commercial and residential projects could occur. However, this approach has not completely removed the need for discretionary approvals for project development. Reports suggest that while form-based codes make initial design approvals more objective, they don’t eliminate discretionary approvals entirely. For instance, developers can request variances (exceptions) if their project faces practical difficulties, and these requests involve the Board of Adjustment making judgment calls. So, it seems likely that the form-based codes have moved discretion to the design approval stage. This means that instead of discretion being about whether a use is allowed, as in traditional zoning, it is now about ensuring designs meet specific standards, like building forms or setbacks, and discretion is not completely insulated from subjectivity and developers’ influence.
UDOs Alone Cannot Solve Everything
As with all policies, there are pros and cons to Unified Development Ordinances. Potential impacts on regulatory and administrative efficiencies, simplifying policies for community stakeholders, and providing a standardized framework for all community members are all promising. UDOs may also significantly improve environmental and sustainability outcomes. However, UDOs may benefit developers disproportionately compared to the community as a whole. While there is potential for greater dense, mixed-use developments that may improve affordable housing access, there are concerns regarding restrictions on certain types of affordable housing and the potential economic segregation. UDOs do not guarantee access to affordable housing. When designing a UDO, policy actors must therefore explicitly state the goals they intend to achieve, set measurable performance indicators for those goals, and critically examine the immediate, medium and long-term direct and indirect impacts of a proposed UDO.