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The Public Right-of-Way Accessibility Guidelines (PROWAG) rulemaking has concluded. The PROWAG final rule has been published in the Federal Register. Please visit the Access Board’s PROWAG page for the guidelines.

Guide to the ABA Accessibility Standards


This guide provides an introduction to the scoping requirements of the ABA Standards and is intended to be used with a complete copy of the ABA Standards since it does not contain or address the full content of the Standards. It is important that users familiarize themselves with the specific scoping requirements contained in the ABA Standards.



cover of the Uniform Federal Accessibility Standards (UFAS)

Additions, alterations, and leasing actions may require retrofit of existing elements. Existing elements that meet earlier editions of the ABA standards, such as the Uniform Federal Accessibility Standards, do not have to be modified to meet the current standards unless altered (§F203.2).

Additions and alterations undertaken at existing facilities are covered by the ABA Standards. The extent of application is largely determined by a project’s scope of work as the standards apply to those elements or spaces that are altered or added. Additional requirements apply to projects that affect or could affect the usability of, or access to, an area containing a primary function. The standards also require certain elements and spaces to comply in existing facilities leased by Federal agencies.



Projects that increase, expand, or extend a facility’s gross floor area or height of a facility are considered additions (as defined in §F106.5) and must comply with requirements of the standards applicable to new construction. However, existing elements and spaces affected by an addition are treated as alterations and qualify for certain allowances or exceptions that are not permitted in new construction.

Application of the Standards in Additions

Existing facility and addition. Figure notes:   Existing portions of a facility affected by an addition are treated as alterations. Newly built portions added to an existing facility are treated as new construction.  An accessible route must connect additions to site arrival points directly or, if an addition does not include an entrance, through an existing facility.  If not provided in an addition, entrances, toilet and bathing facilities, telephones, and drinking fountains provided in existing facilities must be made accessible to serve the addition.

Requirements for Additions

If not included in an addition, these elements and spaces must be made accessible in the existing facility, where provided:

  • toilet and bathing facilities for each sex (an accessible unisex facility is allowed where only 1 toilet or bathing facility is provided or where compliance to multi-user facilities is technically infeasible)
  • a public telephone
  • a drinking fountain

Building with accessible route shown from public sidewalk, accessible parking spaces, and public transportation stop to entrance of addition.  Icons for men’s room, women’s room, drinking fountain, and phone indicated for existing portion of facility.

At least 1 accessible route is required from site arrival points (accessible parking, passenger loading zones, public streets and sidewalks, and transit stops, where provided) to an accessible addition entrance. If the addition does not have its own entrance, an entrance of the existing facility must be made accessible to serve the addition and an accessible route must serve all accessible spaces and elements of the addition.

These requirements apply fully to all additions. Cost caps based on “disproportionality” are not recognized for additions (but are permitted for a path of travel to altered primary function areas).



Alterations are defined in the standards (§F106.5) as “a change in a building or facility that affects or could affect the usability of a building or facility or portion thereof.” Many types of projects are covered as “alterations”, including remodeling, renovation, rehabilitation, reconstruction, restoration, resurfacing of circulation paths or vehicular ways, and changes or rearrangement of structural parts, elements, or walls. Normal maintenance, reroofing, painting or wallpapering, or changes to mechanical and electrical systems are not considered alterations unless they affect a facility’s usability. For example, a project limited to an HVAC system that includes the addition of thermostats would affect a facility’s usability because it involves elements (operable parts) covered by the standards.

The standards ensure that the opportunities for accessibility presented by an alteration are taken. How and to what extent the standards apply is determined by the scope of a project and the elements and spaces altered. Only those elements or spaces altered are required to comply, but alterations made to areas containing a primary function (a major activity for which a facility is intended) also require an accessible path of travel.

Application of the Standards in Alterations

Floor plan with alterations to non-primary function area and to primary function area.  Figure notes:  Altered elements and spaces are required to comply.  In areas not containing a primary function, an accessible route to an altered element or space is required only when the circulation path to the altered element or space is also altered. Alterations made to areas containing a primary function also require an accessible path of travel to the extent that it is not “disproportionate” to the cost. The accessible path of travel must extend to site arrival points, including parking.   If alterations are limited only to elements in a room or space, then the standards apply only to the elements altered. Similarly, where spaces are altered, the standards apply to those spaces that are altered. If a room or space is completely altered (or built new as part of an alteration), the entire room or space is fully subject to the standards. Compliance is required to the extent that it is technically feasible.

Example: Toilet Room Alterations

Figure of toilet room with altered elements highlighted:  toilet, grab bars, faucet controls, and mirror.

In a restroom project involving alterations to the toilet, grab bars, faucet controls, and mirror, the standards apply to these elements but not to those that remain unaltered. In more extensive projects where additional elements are altered, application of the standards is greater, commensurate with the scope of work.

The standards do not require alterations to exceed the level of access required in new construction. For example, spaces that are exempt in new construction are also exempt in alterations.

Prohibited Reduction in Access

New construction requirements also set the baseline for any alteration that would effectively reduce existing accessibility. Alterations that reduce accessibility below the level that would be required in new construction are prohibited. Reductions in access are allowed only where, and to the extent that, the minimum level required in new construction is exceeded. For example, if an alteration will reduce the number of parking spaces on a site, accessible parking spaces can be proportionately reduced as long as the minimum required in new construction (based on the parking facility’s new total) is met. Elements that are not required by the standards to be provided for accessibility, such as phones, can be completely removed from a site.

Special Provisions for Alterations

Page of the standards and magnifying glass

The standards apply the same requirements used in new construction to alterations but also include provisions unique to alterations. Some provisions clarify application, while others are structured as exceptions that limit coverage or relax technical criteria under certain conditions. Located throughout the standards at the relevant scoping or technical requirement, these provisions and exceptions are distinguished by references to “alterations” or “existing facilities.”

escalator symbol
Vertical Access An accessible route to stories and mezzanines is required in alterations (or additions) where stairs or escalators are added where none existed previously and major structural modifications are necessary (§F206.2.3.1) (or as needed to provide an accessible path of travel to an altered primary function area if not disproportionate to the cost (§F202.4)), unless the building is exempt from the requirement for access between stories.
elevator symbol
Elevators If elevators are altered, all cars programmed to respond to the same call control must be similarly modified (§F206.6.1).
fire alarm symbol
Fire Alarms Compliant fire alarm systems are required only in alterations where fire alarm systems are installed new, replaced, or upgraded (§F215.1, Ex. 1).
ramp symbol
Ramps Slightly steeper running slopes are permitted for short ramps (maximum 6" rise) where space is limited (§405.2, Ex.).
stair symbol
Stairs Full handrail extensions at stairs are not required where they would project hazardously into circulation paths (§505.10, Ex. 3).

Technical Infeasibility

Compliance in an alteration is not required where it is “technically infeasible.” The term is defined as “something that has little likelihood of being accomplished because existing structural conditions would require removing or altering a load-bearing member that is an essential part of the structural frame; or because other existing physical or site constraints prohibit modification or addition of elements, spaces, or features that are in full and strict compliance with the minimum requirements.”

Where technical infeasibility is encountered, compliance is still required to the maximum extent technically feasible.

Example of Technical Infeasibility

Floor plan shows toilet room constrained in size by corridor./ min. egress width, stair tower, and elevator and freight elevator shafts

It may be technically infeasible in an alteration to enlarge a toilet room confined in size by structural supports, elevator shafts, mechanical rooms and chases, stairways, or required egress routes not affected by the project. In this case, the toilet room must be sized and other requirements, including those for plumbed fixtures, must be met to the maximum extent technically feasible. However, the concept of technical infeasibility remains relative to the planned scope of work. If the entire building is significantly renovated or gutted, constraints of this type would likely not exist.

Other examples where compliance could potentially be technically infeasible include:

  • conflicts with applicable building, plumbing, life safety or other codes (such as when combining two toilet stalls to create an accessible stall would violate the plumbing code’s required fixture count);
  • meeting slope requirements on existing developed sites located on steep terrain where necessary re-grading and other design solutions are not feasible; or
  • work that would impact load-bearing walls and other essential components of the structural frame, including structural reinforcement of the floor slab.

Alterations Affecting Primary Function Areas


Additional requirements apply when alterations are made to areas containing a “primary function”, which is a major activity intended for a facility. Examples of primary function areas include dining areas of a restaurant, retail space in a store, exam rooms in a doctor’s office, classrooms in a school, and offices and other work areas where the activities of a covered entity are carried out. Spaces not considered primary function areas include entrances, corridors, restrooms, break rooms, employee locker rooms, and mechanical or electrical closets. Restrooms are not primary function areas unless their provision is the primary purpose of a facility, such as a highway rest stop.

Symbols:  Path of travel, restroom, phone, drinking fountain

Accessible Path of Travel

When alterations are made to a primary function area, an accessible path of travel to the area must be provided. The accessible path of travel must extend from the altered primary function area to site arrival points, including public sidewalks and parking and passenger loading zones provided on the site. The path of travel also includes access to restrooms, telephones, and drinking fountains, where provided to serve the primary function area.

Disproportionality (20%)

The accessible path of travel is required to the extent that it is not “disproportionate” to the total cost. Regulations and directives implementing the standards define “disproportionate” as exceeding 20% of the total cost of alterations to the primary function area. The 20% cap applies only to costs associated with the accessible path of travel, including an accessible route to the primary function area, entrances, and retrofits to restrooms, telephones, and drinking fountains.


Additional information on the requirements for alterations to primary function areas is provided in regulations and directives implementing the ABA standards.

Compliance is required up to the point the 20% cost cap is reached, even where it does not result in a fully accessible path of travel. Where costs exceed this cap, ABA standard-setting agencies recommend compliance in this order of priority:

  1. an accessible entrance
  2. an accessible route to the primary function area
  3. restroom access
  4. an accessible telephone
  5. an accessible drinking fountain
  6. accessible parking

Accessible Path of Travel

Plan view:  accessible path of travel shown extending from altered primary function area out of facility to site arrival points (parking, public sidewalk, and public transit stop).  It includes restrooms, drinking fountains, and telephones serving primary function area.  Figure notes:  The accessible path of travel extends from the altered primary function area to site arrival points (public sidewalks, parking, passenger loading zones, public transit stops located on the site).  The path of travel also includes an accessible restroom (for each sex unless only unisex restrooms are provided), telephone, and drinking fountain serving the primary function area, where such elements are provided.

Alterations to Qualified Historic Facilities


Historic designation plaque: "This property has been placed on the National Register of Historic Places"

The standards contain specific provisions for qualified historic facilities which are defined as buildings or facilities that are “listed in or eligible for listing in the National Register of Historic Places or designated as historic under an appropriate State or local law.”

Like other existing facilities, the requirements for alterations apply in relation to the planned scope of work. Alterations provisions and exceptions, including those based on technical infeasibility, and requirements for path of travel to primary function areas, apply equally to historic facilities.

The standards also provide several exceptions where compliance with the standards would threaten or destroy the historic integrity or significance of a facility as determined by the appropriate State Historic Preservation Official or Advisory Council on Historic Preservation. These exceptions apply to requirements for accessible routes (§F206.2) entrances (§F206.4), and toilet rooms (§F213.2).

Exceptions for Qualified Historic Facilities (where compliance would threaten or destroy a facility’s historic significance) Historic facility.  Figure notes:  Vertical access to stories above or below the accessible story is not required (§F206.2.3, Ex. 7).  At least 1 unisex toilet room or 1 men’s and 1 women’s room is required to comply (§F213.2, Ex. 2). At least 1 accessible route is required from a site arrival point to an accessible entrance (§F206.2.1, Ex. 1). At least 1 public entrance is required to be accessible (if that would also threaten the historic significance, access can be provided to a non-public entrance but a notification or remote monitoring system is required for locked entrances) (§F206.4, Ex. 2).



GSA logo

The General Services Administration (GSA) leases facilities on behalf of many federal agencies._ Regulations from GSA and other agencies implementing the ABA standards further explain leasing actions covered.

Existing facilities leased in whole or in part by federal agencies must meet a minimum level of access specified in the standards. These requirements apply when a new lease is negotiated, even when the space was previously occupied by a federal agency. Compliance is not required at facilities that are either leased:

  • for 12 months maximum without renewal or extension options; or
  • on a temporary, emergency basis for government officials providing disaster relief services.

Certain elements, spaces, and routes are required to comply to ensure a minimum level of usability. Other elements are required to comply only if altered or added. Facilities that are built for leasing by federal agencies must fully comply with standards as new construction.

Requirements for Federally Leased Space

Office building with accessible parking spaces and accessible route to accessible entrance. Figure notes:  Parking (§F208) Accessible parking, including van spaces, must be provided based on the number of spaces provided. In multi-tenant facilities, compliance can be limited to the portion allotted the federal tenant.   Accessible Route (§F206) At least 1 accessible route is required from site arrival points (accessible parking, passenger loading zones, public streets and sidewalks, and transit stops, where provided) to an accessible entrance.

Requirements for Federally Leased Space

Entrance to tenant space labeled “National Institute of Health” off elevator lobby.  Figure notes:  Compliance is required where these elements and spaces are provided to serve the leased space (whether located within the space or in joint-use areas serving other building tenants). Fire Alarms (§F215) (unless compliance requires upgrading existing power sources) Drinking Fountains (§F211) Sales and Service Counters (§F227) Public Telephones  (§F217) Accessible Route (§F206) At least 1 accessible route from site arrival points to elements and spaces required to comply and to areas containing a primary function (a major activity for which the facility is intended) Toilet and Bathing Facilities (§F213) At least 1 for each sex on each floor with toilet facilities serving the leased space (access to a unisex facility is allowed in buildings with only 1 men’s and 1 women’s room) Assembly Areas (§F221) and Assistive Listening Systems (§F219)  Dining and Work Surfaces (§F226) Depositories, Vending Machines, Change Machines, and Mail Boxes (§F228)  Residential Facilities (§F233) Existing elements that meet UFAS or other previous ABA standards do not have to be brought into compliance with the current standards unless they are altered.

Common Questions

question mark

What requirements of the standards apply in an alteration?

Application of the standards in an alteration is determined by the scope of work and whether it involves areas containing a primary function. Altered elements or spaces must comply with relevant provisions of the standards except where compliance is technically infeasible. Where compliance is technically infeasible, compliance is required to the maximum extent feasible. If alterations are made to an area containing a primary function (a major activity for which a facility is intended), an accessible path of travel from the area to site arrival points, as well as the restrooms, telephones, and drinking fountains serving the area, must be made accessible as part of the work to the extent it is not “disproportionate” (more than 20% of the total cost).

How is “technically infeasible” determined in an alteration?

Determining “technical infeasibility” requires a site-specific assessment of constraints or complications in relation to the planned scope of work. The term, as defined in the standards (§106), is intended to encompass design, site, engineering or other constraints that prohibit compliance. Examples include work that would impact a facility’s structural frame or that would conflict with applicable codes or building requirements.

Do the standards apply to existing facilities that are not being altered?

The ABA Standards only address existing facilities where alterations or additions occur or where facilities are leased by federal agencies. However, the Rehabilitation Act (section 504) requires access to federally funded or conducted programs and may necessitate retrofits to existing facilities where no other alterations are planned. The obligation to provide “program access” can sometimes be satisfied operationally, such as by relocating a program, but retrofits to remove existing access barriers are often necessary.

Technical Assistance

Contact the Access Board for guidance on these standards