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Designing Sidewalks and Trails for Access

Part II of II: Best Practices Design Guide

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Glossary

Accessible route — A continuous, unobstructed path connecting all accessible elements and spaces of a building or facility that meets the requirements of ADAAG.

Alteration — Modification made to an existing building or facility that goes beyond normal maintenance activities and affects or could affect usability.

Americans with Disabilities Act of 1990 (ADA) — A Federal law prohibiting discrimination against people with disabilities.

Americans with Disabilities Act Accessibility Guidelines (ADAAG) — Provide scoping and technical specifications for new constructions and alterations undertaken by entities covered by the ADA.

Architectural Barriers Act of 1968 (ABA) — A Federal law stating that buildings and facilities designed, constructed, or altered with Federal funds, or leased by a Federal agency, must comply with standards for physical accessibility.

Arterial road — A major through route; arterials often provide direct service between cities and large towns.

Assistive device — A device that assists users in accomplishing day-to-day functions. For example, a wheelchair is an assistive device to assist a person who cannot walk.

Audible warning — A warning consisting of words or sounds indicating a potentially hazardous situation.

Barrier removal — Removal, rearrangement, or modification of objects positioned or structured in a manner that impedes access. Can include rearrangement or removal of furniture or equipment, installation of curb cuts or ramps, or repositioning items such as telephone kiosks or newspaper boxes.

Bevel — A surface that meets another surface at any angle other than 0 or 90 degrees.

Bulbout — Another term for a curb extension, which is a section of sidewalk an intersection or midblock crossing that reduces the crossing width for pedestrians and can help reduce traffic speeds.

Caster — A wheel that can pivot but is not intended to govern the driving direction; typically used for the front wheels of most wheelchairs and strollers.

Change of cross slope — An abrupt difference between the cross slope of two adjacent surfaces. A rapid rate of change of cross slope is frequently found on driveway crossing flares and curb ramps without landings. A cross slope that changes so rapidly that there is no planar surface over 0.6 m2 (24 in2) can create a safety hazard.

Change of grade — An abrupt difference between the grade of two adjacent surfaces.

Changes in level — Vertical height transitions between adjacent surfaces or along the surface of a path. Small changes in level are often caused by cracks in the surfacing material. Changes in level may also result when the expansion joints between elements such as curb ramps and gutters are not constructed at the same time. On trails, ruts caused by weather erosion, tree roots, and rocks protruding from the trail surface are common sources of changes in level.

Charrette — An intensive 1-5 day workshop involving members of a community discussing planning issues, interrelationships, and impacts, and creating their own vision for a project, corridor, neighborhood, or community.

Clear space in crosswalk — The additional space required to be included in a crosswalk at the corner where the ramp of a diagonal curb ramp meets the street, so that those entering or exiting the base of the ramp can remain within the crosswalk.

Collector road — A roadway linking traffic on local roads to the arterial road network.

Commercial facility — Facilities that are intended for non residential use by private entities and whose operation affects commerce.

Comprehensive Master Plan — A broad collection of goals, policies, and objectives adopted by a locality for the purpose of directing the growth of the locality.

Continuous passage — An unobstructed way of pedestrian passage or travel that connects pedestrian areas, elements, and facilities to accessible routes on adjacent sites.

Cross slope — The slope measured perpendicular to the direction of travel.

Curb extension — A section of sidewalk at an intersection or midblock crossing that reduces the crossing width for pedestrians and can help reduce traffic speeds.

Curb ramp — A combined ramp and landing to accomplish a change in level at a curb. This element provides street and sidewalk access to pedestrians using wheelchairs.

Design width — The width specification that a sidewalk or trail was designed to meet. For sidewalks, the design width extends from the curb to any buildings or landscaping that forms the opposite border of the sidewalk. For trails, the design width is the area generally considered part of the trail (the beaten path or tread width).

Detectable warning — A standardized surface feature built in or applied to walking surfaces or other elements to warn people with visual impairments of hazards.

Diagonal curb ramp — A curb ramp positioned at the apex of an intersection.

Diagonal technique — An environmental scanning technique where a visually disabled person holds a cane diagonally across the body in a stationary position, with the cane just above or touching the ground at a point outside one shoulder, and with the handle extending to a point outside the other shoulder. Used primarily in familiar, controlled environments.

Drainage inlet — A site where water runoff from the street or sidewalk enters the storm drain system; the openings to drainage inlets are typically covered by a grate or other perforated surface to protect pedestrians.

Driveway crossing — A ramp positioned where a driveway and the sidewalk meet; designed to ease the transition between the street and driveway.

Finished floor elevation — The elevation at which the building foundation meets the prevailing ground surface.

Firmness — The degree to which a surface resists deformation by indentation when, for instance, a person walks or wheels across it. A firm surface would not compress significantly under the forces exerted as a person walks or wheels on it.

Flare — A sloped surface that flanks a curb ramp and provides a graded transition between the ramp and the sidewalk. Flares bridge differences in elevation and are intended to prevent ambulatory pedestrians from tripping. Flares are not considered part of the accessible route.

Frontage Zone — A linear portion of the sidewalk corridor, adjacent to the edge of the right-of-way (or property line).

Furnishings Zone — A linear portion of the sidewalk corridor, adjacent to the curb, that contains elements such as trees, signal poles, utility poles, street lights, street signs, controller boxes, hydrants, parking meters, driveway aprons, planting strips, or street furniture.

Global Positioning System (GPS) — A system that identifies latitude, longitude, and elevation; a hand console is used to obtain data from an orbiting satellite.

Grade — The slope parallel to the direction of travel that is calculated by dividing the vertical change in elevation by the horizontal distance covered. For example, a trail that gains 2 m in elevation over 40 m of horizontal distance has a grade of 5 percent.

Grate — A framework of latticed or parallel bars that prevents large objects from falling through a drainage inlet but permits water and some sediment to fall through the slots.

Grade-separated crossings — Facilities such as overpasses, underpasses, skywalks, or tunnels that allow pedestrians and motor vehicles to cross a street at different levels.

Gutter — A trough or dip used for drainage purposes that runs along the edge of the trail or street and curb or curb ramp.

Intermodalism — The use of multiple modes of transportation to reach one destination; includes combining the use of trains, buses, automobiles, bicycles, and walking into a given trip.

Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) — Federal legislation authorizing highway, highway safety, transit, and other surface transportation programs from 1991 through 1997. It provided new funding opportunities for sidewalks, shared-use paths, and recreational trails. ISTEA was superseded by the Transportation Equity Act for the 21st Century (TEA-21).

Intersection — An area where two or more pathways or roadways join together.

Island — A pedestrian refuge within the right-of-way and traffic lanes of a highway or street; also used as a loading stop for light rail or buses.

Land management agency — Includes any agency or private organization that manages recreation and/or wilderness areas. Examples of land management agencies include: national entities such as the USDA Forest Service, the USDI Bureau of Land Management, and the USDI National Park Service, as well as State and local park systems.

Landing — A level area of the sidewalk at the top of a curb ramp that faces the ramp path.

Level of Service (LOS) — Qualitative and quantitative measurements of the physical environment for the comfort and efficiency of a mode of travel for pedestrians, bicyclists, or motorists. LOS ratings are A-F, similar to school grading systems. A rating of A (LOS) for one mode may be F for another mode. Balance is needed in order to have a transportation facility that is safe and amenable to all the users.

Local road — A road that serves individual residences or businesses and/or distributes traffic within a given urban or rural area.

Long white cane — Navigational device used by people with vision impairments to scan the environment for potential obstacles and hazards.

Maximum cross slope — The highest cross slope of a trail or sidewalk that exceeds the typical running cross slope of the path. The distance over which a maximum cross slope occurs significantly influences how difficult a section of sidewalk or trail is to negotiate.

Maximum grade — The steepest grade that exceeds the typical running grade. The distance over which a maximum grade occurs significantly influences how difficult a section of sidewalk or trail is to negotiate.

Median — An island in the center of a road that provides pedestrians with a place of refuge and reduces the crossing distance between safety points.

Midblock crossing — A crossing point positioned in the center of a block rather than at an intersection.

Minimum clear width — The narrowest point on a sidewalk or trail. A minimum clear width is created when significant obstacles, such as utility poles or tree roots, protrude into the sidewalk and reduce the design width.

Metropolitan Planning Organization (MPO) — An urban regional body for areas with populations larger than 50,000, that makes transportation policy and planning decisions as mandated in Federal transportation legislation.

New construction — A project in which an entirely new facility is built from the ground up or where a new facility is added to an existing facility.

Obstacle — An object that limits the vertical passage space, protrudes into the circulation route, or reduces the clearance width of a sidewalk or trail. On sidewalks, obstacles are most common in retrofit situations, because accessibility was not considered in the original plan. On trails, obstacles can include objects such as boulders, drop-offs, and tree branches.

Parallel curb ramp — A curb ramp design in which the sidewalk slopes down on either side of a landing at street level; parallel curb ramps require users to turn on the landing before entering the street.

Passing space — A section of path wide enough to allow two users to pass one another or travel abreast.

Passing space interval — The distance between passing spaces.

Pedestrian — A person who travels on foot or who uses assistive devices, such as a wheelchair, for mobility.

Pedestrian actuated traffic control — A push-button or other control operated by pedestrians that is designed to interrupt the prevailing signal cycle to permit pedestrians to cross an intersection.

Pedestrian/bicycle coordinator — A position responsible for planning and managing nonmotorized facilities and programs, creating safety and promotional materials that encourage bicycle and pedestrian transportation, and serving as the principal liaison between government transportation entities, the press, citizen organizations, and individuals on bicycling and walking issues.

Perpendicular curb ramp — A curb ramp design in which the ramp path is perpendicular to the edge of the curb.

Places of public accommodation — Facilities operated by private entities that fall within the following 12 broad categories defined by Congress: places of lodging, food establishments, entertainment houses, public gathering centers, sales establishments, service establishments, transportation stations, places of recreation, museums and zoos, social service establishments, and places of education.

Private entity — An individual or organization not employed, owned, or operated by the government.

Program access — Access provided to a program, service, or activity conducted or funded by a public entity.

Prosthesis — An artificial device that replaces part of the body; includes artificial limbs that serve as assistive devices and enable mobility.

Public entity — Any State or local government, department agency, special-purpose district, or other instrumentality of a State or States or local government, and any commuter authority.

Railroad flangeway — A channel paralleling train or trolley tracks embedded in the travel surface of a road.

Ramp — A sloped transition between two elevation levels.

Reach distance — The three-dimensional space within touching or grasping distance of a pedestrian. As a consequence of their seated position, wheelchair users generally have a more limited reach distance than other pedestrians.

Readily achievable — Easily accomplished and able to be carried out without much difficulty or expense; refers to the criterion for barrier removal under Title III of the ADA.

Reasonable accommodation — Modifications or adjustments to a program, work environment, or job description that make it easier for a person with a disability to participate in the same manner as other employees.

Recreation Access Advisory Committee — A committee established in 1993 by the U.S. Access Board to develop recommendations for accessible recreation facilities.

Recreation trail — A trail that is designed to provide a recreational experience.

Rehabilitation Act of 1973 — A Federal law requiring nondiscrimination in the employment practices of Federal agencies of the executive branch and Federal contractors; requires all Federally assisted programs, services, and activities to be available to people with disabilities.

Removable obstacle — An item that obstructs the clear passage space but is not fixed immovably to the ground. Examples of removable objects include newspaper vending boxes, rocks, vegetation, trash receptacles, and small planters.

Rest area — A level portion of a trail that is wide enough to provide wheelchair users and others a place to rest and gain relief from the prevailing grade and cross slope demands of the path.

Rest area interval — The distance between rest areas.

Right-of-way — The rights, title, and interest in real property necessary for the construction and maintenance of the project. Private property rights may be acquired by donation or acquisition and may be fee-simple, easement, or other form of use agreement acceptable to the parties. The property rights must be of sufficient duration to match the design life of the project, and in a form that can be recorded on the land records.

Running cross slope — The average cross slope of a contiguous section of a sidewalk or trail. Running cross slope is measured by averaging the values of cross slope measurements taken periodically at different points along a given section of sidewalk.

Running grade — The average of many short, contiguous grades.

Section 14 (1994) — Section of the ADAAG containing proposed accessibility guidelines for public rights-of-way (now reserved).

Section 504 (1973) — The section of the Rehabilitation Act that prohibits discrimination by any program or activity conducted by the Federal government.

Shared use path — A trail that permits more than one type of user and that has a transportation and recreation function. An example is a trail designated for use by both pedestrians and bicyclists.

Shy distance — The area along a path generally avoided by pedestrians, such as the areas closest to buildings, retaining walls, curbs, and fences.

Sidewalk — The portion of a highway, road, or street intended for pedestrians.

Sidewalk approach — The section of the sidewalk that flanks the landing of a curb ramp. The approach may be slightly graded if the landing level is below the elevation of the adjoining sidewalk.

Sight distance — The length of roadway visible to a driver or pedestrian; the distance a person can see along an unobstructed line of sight.

Site — A parcel of land bounded by a property line or a designated portion of public right of way.

Slip resistant surface — Slip resistance is based on the frictional force necessary to permit a person to ambulate without slipping. A slip resistant surface does not allow a shoe heel, wheelchair tires, or a crutch tip to slip when ambulating on the surface.

Stable surface — Stability is the degree to which a surface remains unchanged by contaminants or applied force, so that when the contaminant or force is removed the surface returns to its original condition. A stable surface is not significantly altered by a person walking or maneuvering a wheelchair.

Surface — The material on which a person walks or wheels in the pedestrian environment. Sidewalk surfaces generally consist of concrete or asphalt, but commonly include tile, stone, and brick. In addition to concrete and asphalt, trails can be surfaced with dirt, rock, gravel, sand, mud, snow, grass, and other substances.

Surface Transportation Program (STP) — A Federal program that provides grants to States for federally funded roadways and enhancement projects.

Switchback — A trail or road that ascends a steep incline by taking a winding course to reduce the grade of the path.

Title II of the Americans with Disabilities Act of 1990 — The section of the Americans with Disabilities Act of 1990 that prohibits State and local governments from discriminating against people with disabilities in programs, services, and activities.

Title III of the Americans with Disabilities Act of 1990 — The section of the Americans with Disabilities Act of 1990 that prohibits places of public accommodation and commercial facilities from discriminating on the basis of disability. Applies to both private and public entities.

Touch technique — An environmental scanning method in which a blind person arcs a cane from side to side and touches points outside both shoulders. Used primarily in unfamiliar or changing environments, such as on sidewalks and streets.

Trail — A path of travel for recreation and/or transportation within a park, natural environment, or designated corridor that is not classified as a highway, road, or street.

Transportation agency — A Federal, State, or local government entity responsible for planning and designing transportation systems and facilities for a particular jurisdiction.

Transportation enhancement — Projects that enhance the transportation network, including providing bicycle and pedestrian facilities; converting abandoned railroad rights-of-way into trails; preserving historic transportation sites; acquiring scenic easements; and mitigating the negative impacts of a project on a community by providing additional benefits.

Transportation Equity Act for the 21st Century (TEA-21) — Federal legislation authorizing highway, highway safety, transit, and other surface transportation programs from 1998 through 2003.

It provides funding opportunities for pedestrian, bicycling, and public transit facilities and emphasizes intermodalism, multimodalism, and community participation in transportation planning.

Truncated domes — Small domes with truncated tops that are detectable warnings used at transit platforms, curb ramps, and hazardous vehicular ways.

Uniform Federal Accessibility Standards — Accessibility standards that all Federal agencies are required to meet; includes scoping and technical specifications.

Universal Design — The designing of products and environments to be usable by all people, to the greatest extent possible, regardless of age, size, or abilities.

U.S. Access Board (United States Architectural and Transportation Barriers Compliance Board) — The Federal agency that is responsible for developing Federal accessibility guidelines under the ADA and other laws.

Vertical clearance — The minimum unobstructed vertical passage space required along a sidewalk or trail.

Visual impairment — Loss or partial loss of vision.

Water bar — A bar made of materials such as wood, rubber, or stone that is placed across a trail to divert runoff across rather than down the trail.

Wheelchair — Wheeled mobility device used by people with limited or no ability to walk. Wheelchairs can be manually propelled or battery powered.

Wilderness Act of 1964 — A Federal law that prohibits the use of motorized vehicles and mechanized construction on certain tracts of Federally managed land.

Updated: 02/10/2014
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