Accessibility—A term describing the degree to which something is accessible by as many people as possible. In transportation design, accessibility is often used to focus on people with disabilities and their right of access to thoroughfares, buildings and public transportation. Accessibility also refers to transportation facilities that comply with Public Rights-of-Way Accessibility Guidelines (PROWAG).
Access Management—Access management is defined as the management of the interference with through traffic caused by traffic entering, leaving and crossing thoroughfares. It is also the control and regulation of the spacing and design of driveways, medians, median openings, traffic signals and intersections on arterial streets to improve safe and efficient traffic flow on the road system.
Arterial—A street that typically emphasizes a high level of traffic mobility and a low level of property access. Arterials accommodate relatively high levels of traffic at higher speeds than other functional classes and serve longer distance trips. Arterial streets serve major centers of activity of a metropolitan area and carry a high proportion of the total urban area travel. Arterials also serve significant intra-area travel, such as between central business districts and outlying residential areas, between major inner city communities or major suburban centers. Arterial streets carry important intra-urban as well as intercity bus routes.
Articulation—An architectural term that refers to dividing building facades into distinct parts that reduce the appearance of the building's mass adjacent to the sidewalk, identify building entrances and minimize uninviting blank walls.
Bicycle Boulevard—A roadway that motorists may use that prioritizes bicycle traffic through the use of various treatments. Through motor vehicle traffic is discouraged by periodically diverting it off the street. Remaining traffic is slowed to approximately the same speed as bicyclists. STOP signs and signals on the bicycle boulevard are limited to the greatest extent possible, except when aiding bicyclists in crossing busy streets.
Collector—A street that typically balances traffic mobility and property access. Collector streets provide land access and traffic circulation within residential neighborhoods, commercial and industrial areas. Collector streets pass through residential neighborhoods, distributing trips from the arterials through the area to the ultimate destination. Collector streets also collect traffic from local streets in residential neighborhoods and channel it into the arterial system. In the central business district, and in other areas of like development and traffic density, the collector system may include the street grid that forms a logical entity for traffic circulation.
Community—A group of people living within a defined geographic area or political boundary such as a neighborhood, district, town, city, or region. It is both a physical place of streets, buildings, schools and parks and a socioeconomic structure, often defined by qualities including social traits, values, beliefs, culture, history, government structure, issues of concern and type of leadership.
Community Livability—Refers to the environmental and social quality of an area as perceived by residents, employees, customers and visitors, including safety and health, local environmental conditions, quality of social interactions, opportunities for recreation and entertainment, aesthetics and existence of unique cultural and environmental resources.
Context—The nature of the natural or built environment created by the land, topography, natural features, buildings and associated features, land use types and activities on property adjacent to streets and on sidewalks and a broader area created by the surrounding neighborhood, district, or community. Context also refers to the diversity of users of the environment.
Context Sensitive Solutions (CSS)—Collaborative, interdisciplinary process that involves all stakeholders to design a transportation facility that fits its applicable setting and preserves scenic, aesthetic, historic and environmental resources while maintaining safety and mobility. CSS respects design objectives for safety, efficiency, capacity and maintenance while integrating community objectives and values relating to compatibility, livability, sense of place, urban design, cost and environmental impacts.
Context Zone—One of a set of categories used to describe the overall character of the built and natural environment, building from the concept of the "transect"—a geographical cross section through a sequence ranging from the natural to the highly urbanized built environment. There are six context zones plus special districts describing the range of environments including four urban context zones for the purpose of CSS—suburban, general urban, urban center and urban core.
Control Vehicle—A vehicle that infrequently uses a facility and must be accommodated, but encroachment into the opposing traffic lanes, multiple-point turns, or minor encroachment into the roadside is acceptable. A condition that uses the control vehicle concept arises where occasional large vehicles turn at an intersection with low opposing traffic volumes (e.g., a moving van in a residential neighborhood or once per week delivery at a business) or where large vehicles rarely turn at an intersection with moderate to high opposing traffic volumes (e.g., emergency vehicles).
Corridor—A transportation pathway that provides for the movement of people and goods between and within activity centers. A corridor encompasses single or multiple transportation routes or facilities (such as thoroughfares, public transit, railroads, highways, bikeways, etc.), the adjacent land uses and the connecting network of streets.
Corridor Plan—Document that defines a comprehensive package of recommendations for managing and improving the transportation system within and along a specific corridor, based upon a 20-year planning horizon. Recommendations may include any effective mix of strategies and improvements for many modes.
Corridor Planning—Process that is collaborative with local governments and includes extensive public participation opportunities. A corridor may be divided into logical, manageable smaller areas for the purpose of corridor planning.
Design Control—Factors, physical and operational characteristics, and properties that control or significantly influence the selection of certain geometric design criteria and dimensions. Design speed, traffic and pedestrian volumes, location and sight distance are examples of design controls.
Design Vehicle—Vehicle that must be regularly accommodated without encroachment into the opposing traffic lanes. A condition that uses the design vehicle arises where large vehicles regularly turn at an intersection with high volumes of opposing traffic (e.g., a bus route).
Edge Zone—The area between the face of curb and furnishing zone, an area of required clearance between parked vehicles or traveled way and appurtenances or landscaping.
Environment—The natural and built places within or surrounding a community. The natural environment includes the topography, natural landscape, flora and fauna, streams, lakes and watersheds, and other natural resources, while the human/built environment includes the physical infrastructure of the community, as well as its institutions, neighborhoods, districts, and historical and cultural resources.
Frontage Zone—The distance between the through-way and the building front or private property line that is used to buffer pedestrians from window shoppers, appurtenances and doorways. It contains private street furniture, private signage, merchandise displays, etc. The frontage zone can also be used for street cafes. This zone is sometimes referred to as the "shy" zone.
Functional classification—A system in which streets and highways are grouped into classes according to the character of service they intended to provide.
Furnishings Zone—The area of the roadside that provides a buffer between pedestrians and vehicles. It contains landscaping, public street furniture, transit stops, public signage, utilities, etc.
Human Scale—How humans perceive the size of their surroundings and their comfort with the elements of the natural and built environment relative to their own size. In urban areas, human scale represents features and characteristics of buildings that can be observed within a short distance and at the speed of a pedestrian, and sites and districts that are walkable. In contrast, auto scale represents a built environment where buildings, sites, signs, etc. are designed to be observed and reached at the speed of an automobile.
Intermodal—Refers to the connections between transportation modes.
Intersection—Where two or more public streets meet. They are characterized by a high level of activity and shared use, multi-modal conflicts, complex movements and special design treatments.
Local Street—Streets with a low level of traffic mobility and a high level of land access, serving residential, commercial and industrial areas. Local governments typically have jurisdiction for these streets.
Major Thoroughfare—As defined for this report, major streets (and rights-of-way, including improvements between the pavement edge and right-of-way line) in urban areas that fall under the conventional functional classes of arterials and collector streets. Thoroughfares are multimodal in nature and are designed to integrate with and serve the functions of the adjacent land uses.
Mixed-Use—The combining of, or zoning for, retail/ commercial and/or service uses with residential or office use in the same building or on the same site either vertically (with different uses stacked upon each other in a building) or horizontally (with different uses adjacent to each other or within close proximity).
Mixed-use Area—Areas comprised of a mix of land uses, scales and densities that provide some level of internal pedestrian connectivity. The Urban Land Institute (ULI) defines mixed-use as "three or more significant revenue producing uses with significant functional and physical integration of the different uses that conform to a coherent plan."
Mobility—The movement of people or goods within the transportation system.
Multimodal—Refers to the availability of transportation options within a system or corridor whether it be walking, bicycling, driving, or transit.
Multi-use Area—Areas containing two or more land uses that may or may not be complementary and interactive, but that have little or no internal connectivity by any travel mode, and have little or no shared access or shared parking, Nearly all interaction between buildings in this type of area is by motor vehicle travelling on public streets rather than within large parking areas.
New Urbanism—A multidisciplinary movement dedicated to the restoring of existing urban centers and towns within metropolitan regions, reconfiguring sprawling suburbs into real neighborhoods and diverse districts, conserving natural environments and preserving a community's built legacy. The new urbanist vision is to transform sprawl and establish compact, walkable, sustainable neighborhoods, streets, and towns.
(Source: Charter of the New Urbanism and www.cnu.org)
Place/Placemaking—A holistic and community-based approach to the development and revitaliza-tion of cities and neighborhoods. Placemaking creates unique places with lasting value that are compact, mixed-use, and pedestrian and transit oriented, and that have a strong civic character. (Source: www.placemakers.com and Chuck Bohl, "Placemaking")
Public Participation—A collaborative process that encourages stakeholders to participate in the formation, evaluation and conclusion of a plan or transportation improvement project.
Right of way—The publicly owned land within which a thoroughfare can be constructed. Outside of the right-of-way the land is privately owned and cannot be assumed to be available for thoroughfare construction without acquiring the land through dedication or purchase.
Safety—A condition of being safe, free from danger, risk, or injury. In traffic engineering, safety involves reducing the occurrences of crashes, reducing the severity of crashes, improving crash survivability, developing programmatic safety programs and applying appropriate design elements in transportation improvement projects.
Sight Distance—Distance that a driver can see ahead in order to observe and successfully react to a hazard, obstruction, decision point, or maneuver.
Single-use Area—Single-use areas may be corridors or districts which are predominantly comprised of a single type of land use. Often the scale of single-use areas, their lack of a mix of uses and their associated roadway networks tend not to be conducive to walking. Transportation in single-use areas is primarily by motor vehicles, although transit and bicycling can be viable modes. Single-use areas might contain large tracts of housing such as subdivisions or commercial, or industrial uses that rely on freight movement and therefore need to accommodate significant numbers of large vehicles.
Smart Growth—Land use development practices that create more resource efficient and livable communities, with accessible land use patterns. It is an alternative to sprawl development patterns.
Stakeholders—Groups or individuals that have an interest (stake) in the outcome of the planning or project development process. Typical stakeholders include elected officials, appointed commissioners, metropolitan planning organizations, state and local departments of transportation, transit authorities, utility companies, business interests, neighborhood associations and the general public.
Streetside—The public right-of-way, which typically includes the planting area and sidewalk, from the back of the curb to the front property line of adjoining parcels. The roadside is further divided into a series of zones that emphasize different functions including the frontage, throughway, furnishings and edge zones. Transportation facilities, including bus shelters, waiting areas and bicycle parking, may be part of the roadside.
Thoroughfare—As defined for this report, major streets (and their rights-of-way, including improvements between pavement edge and right-of-way line) in urban areas that fall under the conventional functional classifications of arterials and collector streets excluding limited-access facilities. Thoroughfares are multi-modal in nature, and are designed to integrate with and serve the functions of the adjacent land uses.
Throughway Zone—The walking zone that must remain clear both horizontally and vertically for the movement of pedestrians.
Traditional Urban Environments—Places with development pattern, intensity and design characteristics that combine to make frequent walking and transit use attractive and efficient choices, as well as provide for automobiles and convenient and accessible parking. Traditional urban environments typically have mixed land uses in close proximity to one another, building entries that front directly on the street, building, landscape and thoroughfare design that is pedestrian-scale, relatively compact development, a highly-connected, multimodal circulation network, usually with a fine "grain" created by relatively small blocks, thoroughfares and other public spaces that contribute to "placemaking" (the creation of unique locations that are compact, mixed-use, and pedestrian and transit oriented, that have a strong civic character and with lasting economic value).
Transect—A continuum of contexts ranging from the natural and agricultural (parks, open space, farmland) to varying intensities of urbanism (from suburban to urban core). The transect is the basis for the four urban context zones used in this guidance.
Transitions—A change in thoroughfare type, context (e.g., rural to urban), right-of-way width, number of lanes, or neighborhood or district. Geometrically, transitions refer to the provision of a proper smooth taper where lanes or shoulders change width, lanes diverge or merge, or lanes have been added or dropped.
Traveled Way—The public right-of-way between curbs, including parking lanes, and the travel lanes for private vehicles, goods movement, transit vehicles and bicycles. Medians, turn lanes, transit stops and exclusive transit lanes, curb and gutter, and loading/ unloading zones are included in the traveled way.
Traversable Community—Denotes the ability to travel within an area based on the area's size, network connectivity, availability of multimodal facilities, and mix of uses that elicit the need to travel within the area. Large and predominantly single-use districts are most easily traversed by automobile; whereas compact mixed-use districts can be viably traversed by walking or bicycling.
Urban Area—As defined by federal-aid highway law (Section 101 of Title 23, U.S. Code) urban area means an urbanized area as an urban place as designated by the Bureau of the Census having a population of 5,000 or more.
Values—Attributes and characteristics regarded by a community as having ultimate importance, significance, or worth. Community values encompass the natural and built environment, its social structure, people and institutions. The term often refers to a set of principles, standards, or beliefs concerning the elements of the community that are of ultimate importance.
Vision—Part of the process of planning a community that involves residents looking into the future, thinking creatively and establishing what they want their community to be in a 20- or 50-year planning horizon. A vision describes an ideal picture and guides goal-setting, policies and actions by helping to understand community concerns, prioritize issues, determine necessary actions and identify indicators to measure progress. Successful visions include a future that:
Walkable—Streets and places designed or reconstructed to provide safe and comfortable facilities for pedestrians, and are safe and easy to cross for people of all ages and abilities. Walkable streets and places provide a comfortable, attractive and efficient environment for the pedestrian including an appropriate separation from passing traffic, adequate width of roadside to accommodate necessary functions, pedestrian-scaled lighting, well-marked crossings, protection from the elements (e.g., street trees for shade, awnings, or arcades to block rain), direct connections to destinations in a relatively compact area, facilities such as benches, attractive places to gather or rest such as plazas and visually interesting elements (e.g., urban design, streetscapes, architecture of adjacent buildings).
Walkable Communities—Walkable communities possess these two attributes: first, by location, in a mixed-use area within an easy and safe walk of goods (such as housing, offices, and retail) and services (such as transportation, schools, libraries) that a community resident or employee needs on a regular basis. Second, by definition, walkable communities make pedestrian activity possible, thus expanding transportation options, and creating a streetscape that better serves a range of users—pedestrians, bicyclists, transit riders and automobiles. To foster walkability, communities must mix land uses and build compactly, and ensure safe and inviting pedestrian corridors. (Source: www.smartgrowth.org)
Additional Sources of Definitions
Victoria Transport Policy Institute. TDM Encyclopedia Glossary. May 10, 2005. www.vtpi.org/tdm/tdm61.htm.
Federal Highway Administration. FHWA Functional Classification Guidelines, Section II. Concepts, Definitions, and System Characteristics. April 2000. www.fhwa.dot.gov/planning/fcsec2_1.htm.
Metropolitan Transportation Commission (San Francisco Bay Area). Arterial Operations Program Ped/ Bike Safety Toolbox. April 2003. www.bayareatraffic-signals.org/toolbox/Tools/BikeBlvd.html