This guide provides a detailed explanation of the requirements for ramps and curb ramps as stipulated in the Americans with Disabilities Act (ADA) Standards. It serves as an essential resource for architects, builders, and anyone involved in ensuring accessibility in the built environment, aligning with the guide’s condition chapter 20, which emphasizes accessible design specifications.
Where Ramps and Curb Ramps Are Necessary
[§303.4]
Accessible routes mandate the inclusion of ramps and curb ramps to overcome any level changes exceeding ½ inch. Elevators and, under specific conditions, platform lifts, can serve as alternatives. Furthermore, any part of an accessible route with a running slope steeper than 5% must also be treated as a ramp, ensuring continuous accessibility.
Essential Ramp Specifications
[§405]
Alt text: Diagram outlining ADA compliant ramp dimensions: minimum 36-inch clear width, handrails on both sides for rises over 6 inches, maximum 1:12 running slope, maximum 1:48 cross slope, maximum 30-inch rise per run, firm slip-resistant surfaces, edge protection, and level landings.
Delving into Slope and Cross Slope
[§405.2]
Alt text: Image defining ramp slope as the ratio of vertical rise to horizontal run, crucial for ADA compliance and wheelchair accessibility.
Slope, in ADA standards, is defined as the ratio of vertical rise to horizontal length, expressed as a ratio (e.g., 1:12). It can also be represented as a percentage, pitch, or in degrees. The running slope must remain uniform throughout a ramp run, although minor variations may occur with materials like concrete. Crucially, no level changes other than the specified running slope (1:12 maximum) and cross slope (1:48 maximum) are allowed. Variations or breaks in slope within a ramp run can significantly impede wheelchair users.
Clear Width Requirements
[§405.5]
Ramp runs must maintain a minimum clear width of 36 inches, measured between handrails if present. It’s important to note that ramps serving as part of a means of egress may need to adhere to stricter life safety codes, potentially requiring exit widths exceeding 36 inches.
Alt text: Graphic showing how to measure the 36-inch minimum clear width of an ADA ramp, taken between the leading edges of handrails.
Special Considerations for Employee Work Areas
For common use circulation paths within work areas of 1,000 sq. ft. or more, ramp requirements apply with some exceptions:
- The clear width may be reduced below 36 inches if essential work area equipment necessitates it (§405.5).
- Handrails can be installed post-construction if needed, provided the minimum clear width is maintained (§405.8).
Understanding Ramp Rise
[§405.6]
While the height of each ramp run is limited to a maximum of 30 inches, there is no restriction on the total number of runs a ramp system can have. However, extensive ramp systems with numerous runs can be physically demanding for individuals using manual wheelchairs. Intermediate landings offer resting points but do not lessen the overall effort required to navigate multiple runs.
Landings: Essential Rest and Maneuvering Spaces
[§405.7]
Level landings are mandatory at the top and bottom of each ramp run. Level changes exceeding 1:48 are not permitted within landings. Landings must be designed to prevent water accumulation.
Alt text: Illustration showing ADA compliant ramp landings at the top and bottom, minimum 60 inches long and as wide as the ramp run, emphasizing perpendicular grade breaks and a maximum 1:48 slope within landings.
Intermediate landings in ramps that change direction must be at least 60 inches wide and 60 inches long to provide adequate turning space. Handrails, edge protection, posts, and other elements cannot obstruct this minimum 60″ x 60″ clearance. Handrail extensions, required to be a minimum of 12 inches at the top and bottom of runs, must align with the direction of the ramp run but can turn or wrap in continuous handrail designs for switchback ramps.
Alt text: Plan view of an ADA ramp with a 60×60 inch minimum intermediate landing for changes in direction, critical for wheelchair maneuverability.
Intermediate Landings for Directional Changes
Alt text: Detailed diagram of an intermediate ramp landing for turns, noting 60×60 inch minimum size, handrail extension requirements, and recommended run alignment for easier wheelchair maneuvering.
Doorways Integrated with Landings
[§405.7.5]
ADA standards allow required door maneuvering clearances to overlap ramp landings. However, for enhanced safety, it is advisable to position door swings outside of ramp landings.
Doorway Placement at Ramp Landings
Alt text: Illustration of a doorway adjacent to a ramp landing, indicating that while overlap is permitted, locating the door swing outside the ramp landing is recommended for safety.
Handrail Specifications
Handrails are mandatory on both sides of ramps with a rise exceeding 6 inches. While standard ADA guidelines don’t mandate lower handrails for children, except in play areas, they recommend a height of 28 inches maximum and a minimum separation of 9 inches from the required handrail to mitigate entrapment risks.
Handrail Height and Clearance Standards
Alt text: Diagram detailing ADA handrail height requirements (34-38 inches, and 20-28 inches in play areas), and recommended dimensions for lower handrails for children (28 inches max height, 9 inches min separation).
Handrail Continuity and Extensions
Alt text: Graphic illustrating ADA handrail extension and continuity specifications, including 12-inch minimum extensions, return to wall/floor, and continuous gripping surface along the ramp run.
Surface quality and clearance are crucial for enabling a power grip along handrails. Handrails can have circular or non-circular cross-sections but must feature rounded edges. The gripping surface and adjacent areas must be free of abrasive or sharp elements for user safety and comfort.
Circular Cross Section Handrail Details (§505.5, §505.7)
Alt text: Diagram showing ADA specifications for circular handrail cross-sections: 1.25-2 inches diameter with 1.5 inches clearance behind and below, emphasizing knuckle clearance.
Non-Circular Cross Section Handrail Details (§505.5, §505.7)
Alt text: Graphic detailing ADA standards for non-circular handrail cross-sections, including maximum 2.25-inch dimension, rounded edges, 4-6.25 inch perimeter, and 1.5 inch clearance behind and below, less 1/8 inch for each additional 1/2 inch of perimeter.
Aisle Ramps in Assembly Areas
Alt text: Icon representing assembly areas, indicating specific ADA ramp and handrail exceptions applicable in these spaces.
In assembly areas, accessible aisle ramps are exempt from certain handrail requirements. Aisle ramps (or sections thereof) adjacent to seating that are not part of a required accessible route to accessible seating or other accessible elements are not mandated to comply with ramp or handrail specifications.
Aisle ramps that form part of a required accessible route can have handrails on at least one side or within the aisle width, instead of on both sides as typically required for other ramp types (§505.2).
Alt text: Image of an ADA compliant aisle ramp in an assembly area, showing a wall-mounted handrail on one side as permissible.
Handrails on assembly area ramps can be discontinuous and may lack extensions to facilitate seating access and aisle crossovers (§505.3, §505.10).
Other handrail specifications, such as height, clearance, gripping surface, and cross-section, still apply to aisle ramps in assembly areas.
Alt text: Graphic of an aisle ramp in an assembly area with seating on both sides and a discontinuous center handrail, demonstrating allowed handrail configurations under ADA.
Edge Protection: Ensuring Safety on Ramps
[§405.9]
Edge protection is essential along ramp runs and landings to prevent wheelchair casters and crutch tips from slipping off. This can be achieved through curbs, barriers, or extended surfaces.
Edge Protection Options
Curbs must be at least 4 inches high to provide effective edge protection.
Alt text: Image of a 4-inch high curb serving as ADA compliant edge protection for a ramp, preventing wheelchairs from rolling off.
Rails or barriers must prevent the passage of a 4-inch diameter sphere to be compliant.
Alt text: Image of a rail barrier less than 4 inches high, designed to prevent passage of a 4-inch sphere, meeting ADA edge protection standards.
Vertical pickets used for edge protection must also prevent the passage of a 4-inch diameter sphere.
Alt text: Image of vertical pickets with spacing less than 4 inches, used as ADA compliant edge protection to stop a 4-inch sphere from passing through.
Run and landing surfaces extending at least 12 inches beyond the inside face of handrails provide adequate edge protection by preventing wheelchair casters and crutch tips from slipping off.
Alt text: Diagram of an extended ramp platform, projecting 12 inches beyond the handrails, providing ADA compliant edge protection by surface extension.
Edge protection is not required in specific scenarios:
- Ramps no higher than 6 inches with side flares.
- Ramp landings serving an adjoining run or stairway.
- Sides of ramp landings with vertical drop-offs not exceeding ½ inch within 10 inches of the minimum landing area.
Addressing Wet Conditions
[§405.10]
Landings exposed to wet conditions must be designed to prevent water accumulation. Landings are permitted to have slopes no steeper than 1:48 to facilitate drainage, ensuring safety and usability in all weather conditions.
Curb Ramp Requirements
[§406]
Curb ramps, essential for transitions between sidewalks and streets, must comply with specific ADA requirements. These ramps can be cut through curbs or built-up to meet curb level. While new guidelines for public rights-of-way are being developed, the 2010 DOJ ADA Standards mandate curb ramps at new and altered streets, highways, and pedestrian walkways at intersections to provide accessible pedestrian routes (28 CFR 35.151(i)).
Alt text: Diagram outlining ADA compliant curb ramp specifications: top landing for maneuvering, perpendicular grade breaks, maximum 1:10 side flare slope, maximum 1:12 running slope, maximum 1:48 cross slope, and water accumulation prevention.
Smooth Transition to Street
[§406.2]
Alt text: Profile diagram of an ADA curb ramp, emphasizing a smooth transition at the grade break, maximum 1:12 ramp running slope, and maximum 1:20 counter slope.
Top Landing Importance
[§406.4]
The top landing of curb ramps is crucial for providing an accessible connection to the ramp opening. Side flares are primarily for preventing tripping hazards, not for wheelchair maneuvering, except in alterations where landing space is limited. Side flare slopes must not exceed 1:10 (or 1:12 in alterations without a top landing).
Alterations: Ramps without Top Landings
Alt text: Illustration of an altered curb ramp lacking a top landing, using side flares with a maximum 1:10 slope to aid wheelchair maneuvering.
In alterations where top landing space is insufficient, side flares are necessary and cannot exceed a 1:12 slope to facilitate wheelchair maneuvering. Parallel curb ramps offer an alternative in such situations.
Alt text: Diagram of a curb ramp with a sub-36 inch landing, utilizing side flares at a maximum 1:12 slope to accommodate wheelchair users in limited space.
Top Landing Slope Variations
The maximum slope of the top landing is determined by the configuration of connecting accessible routes.
Perpendicular Accessible Route: The cross slope of perpendicular connecting routes limits the ramp top landing slope to 1:48, measured parallel to the running slope.
Alt text: Diagram of a curb ramp top landing with a 1:48 maximum slope, constrained by the cross slope of a perpendicular accessible route, ensuring ADA compliance.
Parallel Accessible Route: If the only connecting accessible route runs parallel to the ramp run, the top landing can have a maximum slope of 1:20.
Alt text: Diagram of a curb ramp with a 1:20 maximum running slope, aligning with the slope of a parallel accessible route, demonstrating slope adaptation for ADA compliance.
Sides of Curb Ramps
[§406.3]
Curb ramps can have returned sides, but a top landing is always required to allow maneuvering to and from the ramp run.
Alt text: Illustration of a curb ramp with returned sides, incorporating a top landing and adjacent planter/grass strip, showing design flexibility within ADA guidelines.
Built-Up Curb Ramps
Built-up curb ramps are permissible but must not encroach into parking spaces, access aisles, or vehicle traffic lanes. A top landing at least 36 inches deep is required for all built-up curb ramps.
Built-Up Curb Ramp with Side Flares
Alt text: Diagram of a built-up curb ramp with maximum 1:10 side flares and a top landing, illustrating ADA compliant construction for curb transitions.
Side flares can be added to prevent tripping hazards. Edge protection specifics are not defined for curb ramps but are generally recommended for safety.
Parallel Curb Ramps
Curb ramps can be oriented parallel to sidewalks, offering a solution where space for a top landing is limited. A level landing at least 48 inches long (60 inches preferred) accommodates maneuvering between runs and right-angle turns to connecting routes, like parking access aisles and crossings.
Alt text: Diagram of a parallel curb ramp with a 48-inch minimum (60-inch preferred) landing between opposing ramp runs, designed for space efficiency and ADA compliance.
Curb Ramps at Intersections
Curb ramps at marked crossings must be entirely within the crosswalk, excluding side flares. While the ADA Standards do not mandate marked crossings, public street crossings are governed by the Manual on Uniform Traffic Control Devices (MUTCD) for Streets and Highways.
Alt text: Illustration of curb ramps at a street corner within marked pedestrian crossings, excluding side flares, demonstrating ADA compliant positioning at intersections.
Curb ramps should be oriented so the grade break is perpendicular to the ramp run for a smooth street transition, particularly at corners with wide radii. The ramp opening can align with the curb line or be directionally oriented towards the crosswalk.
Alt text: Comparative diagram showing curb ramp alignment at corners: one aligned with the curb line, the other directionally oriented to the crosswalk, illustrating design choices for ADA compliance.
Diagonal Curb Ramps
[§406.6]
Alt text: Diagram of a diagonal curb ramp showing a 48-inch minimum clear space at the bottom and 24-inch minimum curb segments for orienting visually impaired pedestrians within marked crossings.
For diagonal curb ramps at intersections, a minimum 48-inch clear space at the bottom, outside vehicle traffic lanes and within marked crossings, is crucial. A curb segment of at least 24 inches beyond flares must be on both sides within marked crossings to provide orientation for people with vision impairments.
Raised Crossings
Alt text: Image of a raised pedestrian crossing, at least 36 inches wide, designed to reduce traffic speed and eliminate the need for curb ramps, enhancing pedestrian safety.
Raised crossings can eliminate the necessity for curb ramps and help reduce traffic speeds. Local standards should be consulted for application requirements, including slope for vehicle traffic, height, and markings.
Islands
[§406.7]
A minimum 48-inch separation between curb ramps on pedestrian islands is necessary to allow wheelchair users to navigate one ramp before the next. Level cut-throughs are an effective alternative, especially for narrow islands that cannot accommodate opposing curb ramps with a 48-inch separation.
Island with Curb Ramps
Alt text: Diagram of a pedestrian island featuring 36-inch minimum wide curb ramps on both sides, separated by a level segment of at least 48 inches, ensuring ADA compliance for island crossings.
Island with Cut-through
Alt text: Diagram of a cut-through pedestrian island with a level accessible route at least 36 inches wide, offering an ADA compliant alternative to curb ramps on narrow islands.
Detectable Warnings
[§406.8]
Alt text: Transit icon, indicating ADA detectable warning requirements at transit facilities like rail and bus stations.
Detectable warnings are required on curb ramps at transit facilities covered by DOT’s Standards (facilities for public transportation services like rail and bus stations). They are not mandated at non-transit facilities under DOJ’s Standards, unless federally funded. New guidelines for public rights-of-way address detectable warnings at curb ramps and transitions on public streets and sidewalks due to higher hazards for visually impaired individuals.
Alt text: Pedestrian icon, representing general considerations for detectable warnings to alert pedestrians to hazards and transitions in public spaces.
Where detectable warnings are required (or provided voluntarily), they must meet specific criteria for size, spacing, and contrast. These detailed specifications ensure a consistent tactile texture to alert individuals to approaching vehicular areas and drop-offs at rail platforms.
Detectable Warnings on Curb Ramps
Alt text: Diagram of a curb ramp with detectable warnings at the base, extending the full run width and 24 inches deep, with light-on-dark or dark-on-light contrast for visual and tactile alert.
Dome Spacing
Alt text: Diagram specifying dome spacing for detectable warnings: 0.65 inch between dome bases and 1.6-2.4 inches between dome centers, ensuring tactile detectability.
Dome Size
Alt text: Diagram specifying dome size for detectable warnings: 0.9-1.4 inch base diameter, 0.2 inch height, and top 50-65% of base diameter, ensuring standardized tactile warning.
Common Questions Regarding ADA Ramps and Curb Ramps
Alt text: Question mark icon, signaling a frequently asked questions section about ADA ramp and curb ramp standards and guidelines.
Ramps
Is there a limit on the total length (number of runs) a ramp may have?
No, while the ADA Standards limit the rise per run to 30 inches maximum, there’s no overall limit on ramp length. However, excessively long ramps should be avoided as usability decreases with length. (Play area ramps are limited to a 12-inch maximum rise).
Are curved or circular ramps permitted?
Ramps without level landings at directional changes often fail ADA compliance due to resulting compound slopes. This includes most curved or circular ramps, unless the radius is large enough to maintain compliant cross slopes and avoid compound slopes. Curvature and slope otherwise create uneven surfaces, hindering wheelchair maneuverability.
Can ramps be portable or added post-construction as an adaptation?
Required ramps and curb ramps must be permanent and installed during construction or alteration, with few exceptions. Post-construction ramps are allowed only for raised workstations in courtrooms (if space was pre-planned) and temporary ramps are only for temporary structures.
Is there a maximum distance between ramp handrails?
No, only a minimum of 36 inches clear width is mandated between handrails. Center or intermediate handrails on wide ramps are not required by ADA standards.
Can handrails overlap ramp landings?
The minimum clear width along runs and landings must be measured to the leading edge of handrails. This rule also applies to 60×60 inch landings at ramp direction changes, ensuring the minimum landing area remains unobstructed.
Can handrail extensions wrap or turn?
Extensions are not needed for continuous handrails in switchback or dogleg ramps or at aisle ramps in assembly areas. In alterations where extensions would dangerously protrude into circulation paths, they can be turned, shortened, or omitted. Otherwise, handrail extensions must follow the ramp run direction.
Can handrails be mounted to guard rails?
Yes, handrails can be installed on guard rails if all ADA requirements are met, ensuring dual functionality and compliance.
Curb Ramps
Why is a top landing required at curb ramps with side flares?
A 36-inch minimum length top landing provides space to approach or exit curb ramps and turn without encountering the compound slopes of flared sides. Side flares primarily prevent tripping hazards and are not designed for wheelchair maneuvering, except in space-limited alterations where they become necessary for partial maneuvering in lieu of a full top landing.
Are side flares mandatory at curb ramps?
No, ADA Standards don’t mandate side flares on curb ramps but limit their slope to 1:10 maximum if provided. Side flares are advisable where pedestrian traffic might cross ramp runs to minimize tripping hazards. They are essential in alterations lacking space for a 36-inch deep top landing, where 1:12 maximum slope side flares become necessary for wheelchair maneuvering, unless a parallel curb ramp is used.
Are detectable warnings required on curb ramps or at hazardous vehicular areas?
Under ADA Standards for site facilities, detectable warnings are required at transit facilities (curb ramps and rail platform drop-offs) under DOT’s ADA Standards. Curb ramps at other facilities generally do not require detectable warnings unless federally funded or specified by local codes. New guidelines for public rights-of-way address detectable warnings on public streets and sidewalks. DOT also requires detectable warnings on curb ramps in federally funded projects.
What facilities fall under DOT’s ADA Standards requiring detectable warnings on curb ramps?
DOT’s ADA Standards cover facilities providing “designated public transportation,” including services by state or local governments to the general public via bus, rail, etc. (excluding aircraft and school transport), and intercity/commuter rail stations. Detectable warnings are specifically required at curb ramps within these transit facilities and at rail platforms with open drop-offs in all transit facilities, including private ones under DOJ’s ADA.
Why are detectable warnings no longer universally required for all curb ramps or hazardous vehicular areas?
Recent ADA Standards updates focus more on site facilities, recognizing separate guidelines for public rights-of-way. Public rights-of-way guidelines will address detectable warnings for hazards on public streets and sidewalks. For site facilities, hazards are mitigated through measures like reduced traffic speeds, marked crossings, pedestrian right-of-way, speed bumps, and other traffic calming methods, reducing the universal necessity for detectable warnings in these controlled environments.
