Research KnowledgeBase

APA's Research KnowledgeBase connects APA members to curated collections of topically related resources — including plans, regulations, model codes, guides, articles, reports, and multimedia files. Each collection provides commentary and thematic groupings of resource records with bibliographic information, short descriptions, and links to the resources themselves.

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  • Accessory Dwelling Units

    An accessory dwelling unit (ADU) is a smaller, independent residential dwelling unit on the same lot as a single-family home. This collection catalogs resources that provide background, policy guidance, and examples of local plan recommendations and zoning standards for accessory dwelling units from across the country.
  • Active Transportation

    This collection catalogs resources that provide background information and demonstrate how local and regional entities are using plans and plan implementation mechanisms in furtherance of active transportation policy goals.
  • Affordable Housing Programs

    Since the late 20th century, many communities have created programs to preserve or expand the local supply of affordable housing. This collection catalogs resources that provide background and policy guidance or demonstrate how local and regional agencies are using regulatory, investment, and assistance programs to promote or protect affordable housing.
  • Age-Friendly Communities

    Age-friendly communities are places where the built and social environment is accessible to and inclusive of all residents — young and old. This collection catalogs resources that provide background and policy guidance or demonstrate how cities and counties are using plans, programs, and regulations to foster accessible and inclusive communities.
  • Agritourism

    This collection catalogs numerous resources that provide background and policy guidance or demonstrate how localities and regional agencies are using plans, regulations, and programs to support farm-based economic development through commercial enterprises that attract visitors to working farms.
  • Artificial Intelligence and Planning

    Artificial intelligence is the study and application of computer algorithms that mimic human decision-making. This collection catalogs resources that provide background and policy guidance on how local and regional planning agencies can use artificial intelligence in their work.
  • Autonomous Vehicles

    Autonomous and connected vehicle technology is expected to transform the nation’s transportation system over the coming decades, with major implications for the planning and design of cities and regions. This collection catalogs resources that provide background, policy guidance, and examples of plans that address autonomous vehicles.
  • Benefits of Compact, Mixed Use Development

    This collection catalogs synthesis and original research articles and reports that illustrate what researchers have learned to date about the costs and benefits associated with compact, mixed use development.
  • Biophilic Planning

    Biophilic planning seeks to strengthen connections between people and nature. This collection catalogs resources that provide background and policy guidance on biophilic planning and demonstrate how local and regional agencies are using plans, regulations, and programs to promote biophilic principles.
  • Brownfields Redevelopment

    Brownfields are previously developed sites that have, or are perceived to have, contamination associated with current or historical land uses. This collection catalogs resources that provide background and policy guidance or demonstrate how cities and counties are using plans, programs, and regulations to promote brownfield redevelopment.
  • Built Environment and Health

    Planning evolved as a response to issues in the built environment, like overcrowding, that contributed to public health crises. This collection catalogs resources that provide background, research, and policy guidance or demonstrate how local and regional agencies are using plans, regulations, and programs to guide change in the built environment to improve health outcomes.
  • Capital Improvements Programming

    Capital improvements programming is a plan implementation technique that involves prioritizing and scheduling investments in public facilities and infrastructure over a multi-year period. This collection catalogs resources that provide background and policy guidance or demonstrate how localities are using multi-year capital investment programs as plan implementation tools.
  • Climate Change

    Planners have a responsibility to help shape and implement plans that decrease greenhouse gas (GHG) emissions and protect communities from climate-related hazards. This collection catalogs resources that provide background and policy guidance on climate change and action and demonstrate how local and regional agencies are using plans, programs, and regulations as climate action tools.
  • Community Visioning

    Community visioning is a participatory planning process that seeks to describe an agreed-upon desired future for a community. This collection catalogs resources that provide background, procedural guidance, case studies, and examples of local documents that illustrate various aspects of the community visioning process.
  • Complete Streets

    Complete streets is an approach to planning and designing streets and street networks that prioritizes safe and convenient access for all modes and users. This collection catalogs resources that provide background and policy guidance, as well as examples that demonstrate how localities are using plans, policies, and regulations to consider all modes of transportation in the design of streets.
  • Comprehensive Planning

    A comprehensive plan is an official statement that sets forth goals, policies, and guidelines intended to direct a jurisdiction's present and future development. This collection catalogs resources that provide background information, comprehensive plan development guidance, and examples of potentially noteworthy plans from various types of communities across the country.
  • Conflict Management in Planning

    Conflict is an inevitable part of any collective effort to manage change in communities. This collection catalogs resources that provide background information and practical guidance exploring conflict management principles, the roles planners play in managing conflicts, and specific tools and techniques planners can apply in their work.
  • Content-Neutral Sign Regulation

    The U.S. Supreme Court’s 2015 decision in Reed v. Town of Gilbert re-emphasized the importance of content neutrality in sign regulation. This collection catalogs resources that provide background and examples of local sign codes revised based on the Reed decision as well as others that adhere to the principle of content neutrality.
  • Creative Placemaking

    Creative placemaking is a process where community stakeholders use arts and cultural strategies to implement community-led change. This collection catalogs resources that provide background and policy guidance or demonstrate how community stakeholders are using plans, regulations, and programs that support the arts and cultural activities.
  • Design Review

    Design review is a process by which development projects are reviewed against architectural and site design criteria, in many cases by a specially designated design review board or committee. This collection catalogs resources that provide background, policy guidance, and examples of local design guidelines and process guides from across the country.
  • Design Thinking in Planning

    Design thinking is a human-centered design approach that uses an iterative five-step process: researching, reframing, ideating, prototyping and iterating. This collection catalogs resources that provide background and procedural guidance on using design thinking techniques in the context of planning.
  • Digital Twins and Planning

    Digital twins are virtual representations of physical objects or systems that integrate real-time data to enable monitoring and simulation. This collection catalogs resources that provide background and policy guidance on the development of digital twins as planning-support tools and demonstrate how local and regional agencies are using digital twins to guide policy and implementation.
  • Downtown Revitalization

    Downtowns are powerful symbols. For many visitors and residents, a vibrant downtown equals a healthy city. This collection catalogs resources that provide background and policy guidance and demonstrate how specific cities and counties are using plans, programmatic investments, and regulations to revitalize downtowns.
  • Electric Vehicle Infrastructure

    This collection catalogs resources that provide background and policy guidance on the deployment of charging stations for electric vehicles and demonstrate how local and regional agencies are using plans, regulations, and programs to expand electric vehicle infrastructure.
  • Environmentally Sensitive Areas

    Environmentally sensitive areas (ESAs) are environmental features that are susceptible to adverse impacts from new development. This collection catalogs resources that provide background, policy guidance, or examples of local plans and regulations aimed at protecting environmentally sensitive areas.
  • Farmland Protection

    This collection catalogs numerous resources that provide background and policy guidance or demonstrate how localities and regional agencies are using plans, regulations, and programs to protect and preserve agricultural lands.
  • Food Systems

    Food systems are the chain of activities connecting food production, processing, distribution, consumption, and waste. This collection catalogs resources that provide background, policy guidance, model ordinances, and examples of local and regional plan recommendations and development regulations for various types of activities and uses that promote food access or security from across the country.
  • Food Trucks

    Food trucks can add interest, vibrancy, and activity to underutilized spaces and can expand food access in areas underserved by traditional restaurants. This collection examples of resources that provide background and policy guidance or demonstrate how localities are regulating and assisting mobile food vendors.
  • Form-Based Zoning

    Form-based zoning is an approach to zoning that emphasizes built form over land use. This collection catalogs resources that provide background and policy guidance on form-based zoning, as well as examples of local form-based codes.
  • Grayfields Reuse and Redevelopment

    Currently, many cities and counties across the U.S. have a large supply of vacant or underutilized auto-oriented commercial properties. This collection catalogs resources that provide background, policy guidance, and examples of local plan recommendations and zoning standards to facilitate the reuse or redevelopment of abandoned or underutilized commercial properties.
  • Green Building

    Green building encompasses a wide range of planning, design, and construction practices that seek to improve the environmental performance of buildings. This collection catalogs resources that provide background and policy guidance or demonstrate how cities and counties are using plans, regulations, and programs to require or incentivize green building practices.
  • Green Stormwater Infrastructure

    Green stormwater infrastructure uses (or mimics) natural processes to reduce or treat stormwater runoff. This collection catalogs resources that provide background and policy or design guidance, as well as examples that demonstrate how localities are using plans, regulations, and programs to minimize dependence on gray infrastructure for stormwater management.
  • Group Housing

    A group home is a dwelling unit occupied as a single housekeeping unit by a small number of unrelated individuals. This collection catalogs resources that provide background, policy guidance, and examples of plan recommendations and zoning regulations for various types of group living situations.
  • Hazard Mitigation

    Hazard mitigation is any sustained action taken to reduce or eliminate the risk of property damage or injuries from natural or human-caused disasters. This collection catalogs resources that provide background and policy guidance or demonstrate how cities and counties are using plans, programs, and regulations to mitigate natural and human-caused hazard risks.
  • Historic Preservation

    Historic preservation is the practice of protecting and preserving buildings, sites, and districts that have historical or cultural significance. This collection catalogs resources that provide background and policy guidance or demonstrate how cities and counties are using plans, regulations, and programs to protect and enhance historic buildings, sites, and districts.
  • Home Occupations

    In zoning, a home occupation is any business operated (or paid work performed) by a resident as an accessory use to a dwelling unit. This collection catalogs examples of resources that provide background and policy guidance or demonstrate how localities are regulating and assisting home-based businesses.
  • Housing Supply Planning

    Urban, suburban, and rural communities across the United States face a housing shortage. This collection catalogs resources that provide background and policy guidance on housing supply planning and examples of local housing needs assessments, plans, and plan implementation tools from across the country.
  • Improving Development Review

    The development review process should be predictable, efficient, and open, and it should add value to the community. This collection catalogs resources that provide background, policy and procedural guidance, and examples of local organizational or procedural evaluations aimed at improving the efficiency or efficacy of local development review.
  • Inclusionary Housing

    Inclusionary housing programs link affordable housing provision to private development by requiring or incentivizing developers to construct affordable housing units as part of market-rate residential projects. This collection catalogs resources that provide background and policy guidance or demonstrate how localities are using plans and development regulations to promote inclusionary housing.
  • Integrated Water Resource Management

    Integrated Water Resource Management looks holistically at the planning and management of water supply, wastewater, and stormwater systems. This collection catalogs resources that provide background and policy guidance or demonstrate how local, regional, and state agencies are using plans, regulations, and programs to manage water resources in an integrated way.
  • Introducing Planning Concepts to Nonplanners

    While the practice and profession of planning has broad effects on all segments of society, many community stakeholders have a limited understanding of fundamental planning concepts. This collection catalogs resources that can help introduce and explain planning fundamentals to nonprofessional audiences, including reports, articles, handouts, guidebooks, activities, and educational curricula.
  • Marijuana-Related Uses

    Many cities and counties are exploring whether or how to make space for marijuana-related land uses without undermining public health, safety, or welfare. This collection catalogs resources that provide background, policy guidance, and examples of local zoning and licensing regulations for marijuana-related uses.
  • Measuring Planning Department Performance

    To improve their function and performance, planning departments may set goals and objectives and use performance measures to track departmental performance and accomplishments. This collection catalogs resources that provide background on and examples of performance metrics used by various planning agencies across the country.
  • Neighborhood Planning

    A neighborhood plan presents a vision and a strategy to guide change within a discrete, contiguous, predominantly residential subarea of a city. This collection catalogs resources that provide background and policy guidance on planning for discrete, contiguous, predominantly residential subareas of cities, as well as examples of locally adopted neighborhood plans.
  • Online Public Engagement

    Online public engagement is an umbrella term for public-sector efforts to notify, inform, consult, or collaborate with community members through websites and web applications. This collection catalogs resources that provide background and policy guidance as well as resources that explain or illustrate how local and regional agencies are using online public engagement tools and techniques.
  • Outdoor Lighting

    This collection catalogs resources that provide background and policy guidance or demonstrate how localities are using plans and regulations to minimize light pollution associated with human settlements.
  • Planning and Zoning Enabling Laws

    State statutes establish the framework for local planning activities. Through these laws, states delegate power to local governments to prepare comprehensive plans and adopt zoning and other land-use and development regulations. This collection catalogs resources that provide background on those state laws as well as the laws themselves.
  • Residential Infill Development

    Residential infill development refers to the development of new housing on vacant or underutilized land in previously developed areas. This collection catalogs resources that provide background information and demonstrate how local and regional entities are using plans and plan implementation mechanisms to guide successful residential infill development.
  • Rethinking Off-Street Parking Requirements

    Since APA published the High Cost of Free Parking in 2005, many cities and counties across the U.S. have reevaluated their approaches to requiring off-street parking for all new land uses and development. This collection catalogs resources that provide background, policy guidance, model ordinances, and examples of local policy-driven off-street parking requirements.
  • Scenario Planning

    Scenario planning enables professionals, and the public, to respond dynamically to an unknown future. This collection catalogs resources that provide information about developing and using scenarios in local and regional planning.
  • Scenic View Protection

    This collection catalogs resources that provide background and policy guidance or demonstrate how localities are using plans, regulations, and programs to protect natural or rural vistas and viewsheds from visual obstructions.
  • Shared Mobility

    Shared Mobility refers to transportation services that provide users with short-term access to transportation modes on an as-needed basis. This collection catalogs resources that provide background and policy guidance or demonstrate how local and regional agencies are taking action to accommodate or encourage ridesourcing; bike, car, and scooter sharing; ridesharing; and microtransit services.
  • Short-Term Residential Rentals

    This collection catalogs resources that provide background and policy guidance, as well as examples of local regulations, that address short-term residential rentals.
  • Small Wireless Facilities and Wireless Facilities in the ROW

    This collection catalogs resources that provide background, policy guidance, model ordinances, and examples of local development regulations for small wireless facilities and wireless facilities in public rights-of-way.
  • Smart Cities

    A “smart city” uses information and communication technology (ICT) to optimize citizen engagement, service delivery, and systems performance. This collection catalogs resources that provide background and policy guidance, as well as examples of local uses of information and communications technology to engage citizens, deliver services, and enhance urban systems.
  • Social Equity

    Social equity means all community members can participate, prosper, and reach their full potential. Explore this collection of resources that provide background, research, and policy guidance or demonstrate how local and regional agencies are using plans, regulations, and programs to advance social equity goals.
  • Solar Energy

    This collection catalogs resources that provide background and policy guidance on solar energy use, as well as examples of local plans and regulations that support solar development.
  • Tactical Urbanism

    The term tactical urbanism refers to any temporary, low-cost intervention in the built environment. This collection catalogs resources that provide background and policy guidance related to or examples of local programs and policies for temporary, low-cost interventions in the built environment.
  • Tiny Houses and Micro Apartments

    While the average amount of living space per person continues to grow in the U.S., there is a growing interest among property owners and residents in many communities in micro housing. This collection catalogs resources that provide background, policy guidance, and examples of local development regulations for tiny houses, tiny house subdivisions, and micro apartments from across the country.
  • Transfer of Development Rights

    This collection catalogs resources that provide background on or policy guidance for transfer of development rights (TDR) programs as well as examples of local plans and development regulations that demonstrate specific approaches to TDR.
  • Transit-Oriented Development

    This collection catalogs numerous resources that provide background and policy guidance on, or examples of, how communities are using plans and regulations to facilitate higher-density mixed use development within walking distance of mass transit stations.
  • Tree Preservation and the Urban Forest

    A healthy urban forest provides environmental, social, and economic benefits. This collection catalogs resources that provide background, policy guidance, and examples of how cities and counties are using plans and regulations to protect trees and expand urban tree canopies.
  • Urban Agriculture

    This collection catalogs resources that provide background and policy guidance or demonstrate how metropolitan localities are using plans, regulations, and programs to advance food production goals through urban agriculture uses.
  • Urban Heat Resilience

    Extreme heat is one of the deadliest climate risks in the United States. This collection summarizes the state of the practice regarding local and regional efforts to mitigate and manage urban heat effects. And it catalogs resources that provide background and policy guidance or demonstrate how local and regional agencies are using plans, programs, and regulations to boost resilience to urban heat.
  • Urban Livestock

    This collection catalogs numerous resources that provide general background, policy guidance, and examples of local regulatory provisions governing the keeping of farm animals and poultry in urban areas.
  • Wildland-Urban Interface

    The wildland-urban interface (WUI) is defined as the area where human development borders or intermingles with forests or other wildlands. This collection catalogs resources that provide background and policy guidance or demonstrate how communities are using plans, regulations, and programs to address wildfire and other challenges in the WUI.
  • Wind Energy

    This collection catalogs resources that provide background and policy guidance on wind energy use, as well as examples of local plans and regulations that support wind development.
  • Youth in Planning

    Successful youth engagement in planning strengthens civic infrastructure and elevates the perspectives of those with the greatest stake in the future. This collection catalogs resources that provide background on, policy guidance for, and examples of local and regional efforts to engage youth in planning and land use decision-making processes.
  • Zoning Reform and Code Writing

    Zoning is among the most powerful tools local governments have to control future land use and development. This collection catalogs resources that provide general background, policy and process guidance, and examples of code evaluation reports and noteworthy recent zoning and development codes from various types of communities across the country.