Useful definitions and acronyms


Accessory dwelling unit (ADU)
Secondary housing unit on a single-family lot, also known as a ‘granny flat’
Adaptive reuse
The process of reusing an existing building for a purpose other than which it was originally built or designed for 
Autonomous vehicle (AV)
A vehicle that is capable of sensing its environment and moving safely with little or no human input, also known as a self-driving car


Blighted property
A property that is dilapidated, unsafe, and/or in an unsightly condition
A former industrial or commercial site where future use is affected by real or perceived environmental contamination
Built environment
Consists of buildings, parks, roads, infrastructure, and other physical parts that set the stage for human activity within a city; the human-made space in which people live, work, and recreate on a daily basis
Business improvement district
A commercial district in which property owners or businesses pay an additional tax or fee in order to fund supplemental services or improvements within the district’s boundaries


Carbon neutrality
Achieving net zero carbon dioxide emissions by balancing carbon emissions with carbon removal or simply eliminating carbon emissions altogether
Code enforcement
A process whereby local governments use various techniques to gain compliance with adopted regulations such as land use and zoning ordinances, health and housing codes, sign standards, and uniform building and fire codes
Commercial zoning
Retail and business uses such as shops, convenience stores, big box stores, and restaurants
Context-sensitive development
An approach to the planning and design of transportation projects that balances competing needs of stakeholders, addresses all modes of travel, applies flexibility in inherent design standards, and balances safety, mobility, community, and environmental goals in all projects
A dead-end street, particularly one with a circle for turning around at the end, usually found in suburban residential neighborhood


The rate of people living within a uniform geographic area, such as people per acre or people per square mile
(2-family): one building housing two "families" in two separate housing units that are on top of one another or next to each other


The ratio of building height to street width; good sense of enclosure means that the height of the buildings is in proportion to the width of the intervening public space
Euclidean zoning
Single-use zoning that specifies what uses are allowed on a specific parcel of land


Facade improvement program
Incentive program designed to help property owners or tenants renovate or rehabilitate the entire façade of their building in projects that promote retail activity, create an attractive environment, encourage high-quality architectural design, use high-quality materials, and enhance neighborhood character
The 100-year floodplain represents areas that have a 1% chance of flooding in a given year, or once every 100 years. The 500-year floodplain represents areas that have a 0.02% chance of flooding in a given year, or once every 500 years
Food desert
An area that has limited access to affordable and nutritious food from grocery stores or vegetable shops


Governmental zoning
Uses that are owned or operated by a government agency such as the Commonwealth of Virginia, the City of Richmond, or the federal government. These include facilities such as police and fire stations, libraries, and City Hall
The relatively clean wastewater from baths, sinks, washing machines, and other appliances that may be re-used for non-consumable purposes, such as watering lawns


Heat island effect
An urban area that is significantly warmer than its surrounding areas due to urban elements such as buildings, roads and pavements, and lack of vegetation and shade
Heat vulnerability index
A measure of how likely a person is to be injured or harmed during periods of hot weather, especially young children and older adults
High speed rail
A type of rail transport that operates significantly faster than traditional rail traffic
Historic preservation
The practice of protecting and preserving sites, structures, or districts which reflect elements of local or national cultural, social, economic, political, archaeological, or architectural history


Impervious surface
Describes paved areas like roads and parking lots, and other hard surfaces like building roofs, that do not absorb rainwater but rather allows the water to runoff into other areas and waterbodies
Industrial zoning
Industrial uses such as production, processing, manufacturing, and warehousing, distribution, and logistics
Institution zoning
Institutions such as universities, schools, museums, theaters, and places of worship, which are typically not-for-profit organizations
Intelligent transportation systems (ITS)
Applies advanced sensing, analysis, control, and communications technologies in various transportation systems in order to improve safety, efficiency, and service


Land bank
Entities that acquire, maintain, and return vacant and blighted property to productive uses
All of the visible features of an area of countryside, land or street, often considered in terms of their aesthetic appeal
Light pollution
The presence of human-generated and artificial light in the night environment, inhibiting the observation of stars and planets


An architecture term which refers to the perception of the general shape and form as well as the size of a building
Mixed-use zoning
A building or parcel with more than one use. Refers to either a building with different uses in it (such as a store, restaurant, or office on the ground floor with residences above), or to a parcel of land with more than one use on it
Multi-family zoning
One building with three or more dwelling units in it that are either condominiums (each unit is owned individually) or apartments (each unit is rented and the entire building is owned by one entity)


Office zoning
General office space for medical, professional, and research and development businesses
On-demand transit
A mode of public transportation that differs from traditional, fixed-route transit, in that a user may request a ride with a customized origin and destination


The relationship of a building to its street that is enhanced with the inclusion of elements such as entrances and windows
An approach to planning, design, and organization of public spaces that capitalizes on an area's assets; the goal is to create quality public spaces with strong character that encourages health and equity
Priority streets
A zoning designation that requires a street to be considered in the same way as a “principal street” (the highest order street fronting a parcel) which restricts driveway entrances and parking areas to enhance the pedestrian experience
Public art
Art in any media that has been planned and executed with the intention of being staged in the physical public domain, usually outside and accessible to all
Public open space
Publicly-owned land that features City parks or other types of open space such as cemeteries
Public realm
Includes all exterior places, linkages, and built form elements that are physically and/or visually accessible regardless of ownership; defined as any publicly-owned streets, right-of-ways, parks, publicly-accessible open spaces, and any public and civic buildings and facilities


The capacity of individuals, communities, institutions, businesses, or systems within a city to survive, adapt, and grow no matter what kinds of chronic stresses or acute shocks they experience
Resource Management Area (RMA)
As defined by the Chesapeake Bay Preservation Act: includes all Resource Protection Areas plus the 100-year floodplain, soils that erode easily, steep slopes, non-tidal wetlands, 500-foot separation from Resource Protection Area and 600-foot separation from streams
Resource Protection Area (RPA)
As defined by the Chesapeake Bay Preservation Act: includes land next to water bodies and land, that if developed, may worsen water quality of water bodies; includes tidal wetlands, non-tidal wetlands, water bodies that flow continuously (i.e. rivers and streams), tidal shores, other land that should be protected to improve water quality, and land within a 100-foot strip next to all previously listed areas
Refers to completely changing a parcel's zoning designation to a different one, or a conditional rezoning where the City places conditions on an owner-requested zoning change such as limiting the height of the building or requiring certain improvements on- or off-site; the conditions cannot lessen the requirements of an existing zoning district
Right-of-way (ROW)
The legal right to pass along a specific route through grounds or property belonging to another
Riparian area
The interface between land and a river or stream


Safe Routes to School
An approach that promotes walking and biking to school through infrastructure improvement, enforcement, tools, safety education, and incentives
The area between a building and the property line. Typically, commercial buildings have shallow setbacks, and residential buildings have deeper setbacks
Shared-use path
A form of infrastructure that supports multiple recreation and transportation opportunities, such as walking, biking, and more
Single-family zoning
Detached houses and attached rowhouses with one "family" per house
Small area plan
Defines a vision for redevelopment in a relatively small area of a city
Special Use Permit (SUP)
Allows for an applicant to receive approval for a development that does not conform to the existing zoning district
Street furniture
Objects placed or fixed in the streets for public use, such as mailboxes, road signs, and benches
Water that originates during precipitation events and snow/ice melt, which can infiltrate soil, evaporate, or become runoff that ends up in nearby water bodies


Transit-oriented development (TOD)
Walkable development served by frequent transit with a mix of housing, retail, and employment choices designed to allow people to live and work with less or no dependence on a personal car
Transportation demand management (TDM)
The application of strategies and policies to reduce travel demand by informing, encouraging, or incentivizing the public to use non-driving options
Traditionally marginalized
Groups of people who have historically been oppressed or treated as insignificant and excluded from public decision-making processes, such as women, people of color, the disabled, LGBTQ+ populations, and more
Tree canopy
The layer of leaves, branches, and stems of trees that cover the ground when viewed from above


Urban design
The process of creating the public realm through the artful arrangement of buildings and site elements as cities grow and change; successful urban designs create meaningful spaces that foster positive social interaction, cultural advancement, and civic identity


Vacant parcels
Parcels of land that are not developed
A geographical area that is visible from some location
Vision Zero Action Plan
A multidisciplinary, global strategy to eliminate all traffic fatalities and severe injuries, while increasing safe, healthy, and equitable mobility for all


A land area that channels rainfall and snowmelt to creeks, streams, and rivers, and eventually to outflow points such as reservoirs, bays, and the ocean
Land that is saturated in water, either permanently or seasonally and are important for the following reasons: they absorb water during rain and therefore help reduce flooding; help clean pollutants out of water; allow water to slowly seep into the ground and replenish groundwater; and are habitats for many different types of animals