ADA Accessible Route Requirements: Width, Slope, and Clearance

ADA accessible route requirements set a single, enforceable rule: at least one continuous, unobstructed path must connect every site arrival point to an accessible entrance, and from that entrance to every room and space required to be accessible inside. That path has to be wide enough, gentle enough, and clear enough for a person using a wheelchair, walker, or cane to travel independently. The 2010 ADA Standards for Accessible Design spell out the numbers, and most compliance failures come down to missing one of them during design or letting the route degrade after occupancy.¹

Where an Accessible Route Has to Go

At least one accessible route must connect each site arrival point to an accessible building entrance. Site arrival points include accessible parking spaces, passenger loading zones, public transportation stops, and public streets or sidewalks. Someone arriving at the property boundary should never find themselves stuck with no usable way to reach the door.¹

Inside, the route has to connect the entrance to every accessible room and space. On sites with more than one building, the paths between buildings must also be accessible: no stairs-only connections, no steep unpaved shortcuts. The rule applies to offices, retail, recreational facilities, and every other type of public accommodation or commercial facility.²

Entrances themselves are counted. In new construction, at least 60 percent of all public entrances must be accessible. Public entrance means every entrance that is not restricted (secured by more than a key card) or used only for service. Entrances that directly serve tenant spaces, parking facilities, pedestrian tunnels, and elevated walkways must be accessible on top of that 60 percent calculation. An employee entrance controlled by a standard badge reader is not exempt.³

Minimum Width and Turning Space

The clear width of an accessible route must be at least 36 inches along its entire length. That is what a standard wheelchair needs to travel without scraping walls or fixtures. The path can narrow to 32 inches for a maximum distance of 24 inches, which is what allows a standard doorway to interrupt a corridor, but it has to return to 36 inches immediately after.² Doors along the route also need clear floor space on both sides so a wheelchair user can approach, open the door, and pass through without reversing into traffic.

Wherever the route requires a change of direction, the design has to include a wheelchair turning space. Two configurations satisfy the rule: a circle at least 60 inches in diameter, or a T-shape at least 60 inches wide and 60 inches deep. Elements with knee and toe clearance underneath, like a counter or a sink, can overlap that turning space. Dead-end corridors, single-user restrooms, and elevator lobbies are the places designers forget, and those are the places where a wheelchair user can end up literally unable to turn around.⁴

Passing Spaces on Narrow Routes

When the accessible route is less than 60 inches wide, passing spaces have to appear at least every 200 feet. Each one must measure at least 60 by 60 inches. A T-shaped intersection with arms extending at least 48 inches from the center also qualifies. The idea is simple: two wheelchair users meeting on the path shouldn’t need one of them to reverse the length of a corridor.¹

Overhead Clearance and Protruding Objects

Overhead clearance along the route must be at least 80 inches. At doorways a slight reduction to 78 inches is permitted to accommodate closers and stops. Where any beam, sign, sloped ceiling, or architectural element drops below 80 inches over a circulation path, a cane-detectable barrier has to be installed beneath it. The barrier’s leading edge cannot sit higher than 27 inches above the floor, so a person sweeping a white cane will find it.⁵

Objects mounted on walls between 27 and 80 inches above the floor cannot project more than 4 inches into the circulation path. That vertical band sits above the reach of a cane sweep and below head-clearance height, which is what makes protrusions in that range dangerous. Fire extinguisher cabinets, wall sconces, display cases, and defibrillator units are the usual offenders. They have to be recessed or placed inside a cane-detectable alcove. Anything mounted at or below 27 inches is already cane-detectable, and anything above 80 inches falls under overhead clearance, so the 4-inch limit applies only to that middle band.⁵

Slope, Cross Slope, and When a Walkway Becomes a Ramp

Running slope is measured in the direction of travel. A surface qualifies as a standard walkway only if its running slope stays at or below 1:20. Once it exceeds 1:20, the surface is classified as a ramp and has to meet a stricter set of rules for handrails, edge protection, and landings.⁶

Cross slope, the tilt running perpendicular to the direction of travel, cannot exceed 1:48 anywhere on an accessible walking surface or ramp. Excessive cross slope is one of the most litigated failures because it forces wheelchair users to fight sideways drift for the entire length of the path.⁷

Ramp Rules

When a ramp is required, its running slope cannot exceed 1:12. Each ramp run is limited to a maximum rise of 30 inches. There is no cap on the number of runs a ramp can have, so long elevation changes are handled by adding more runs with landings between them.⁸ Existing buildings get narrow exceptions where space is tight: up to 1:10 for a maximum rise of 6 inches, or up to 1:8 for a maximum rise of 3 inches.⁷

Level landings are required at the top and bottom of every ramp run. Each landing must be at least 60 inches long and at least as wide as the ramp it serves. Where a ramp changes direction, the intermediate landing must be at least 60 by 60 inches, and handrails, edge protection, and vertical posts cannot encroach on that clearance.⁷

Handrails are required on both sides of any ramp run with a rise greater than 6 inches. They have to be continuous for the full length of the run, with 12-inch extensions at the top and bottom so users have something to hold before stepping onto or off the ramp. Handrail height falls between 34 and 38 inches above the ramp surface. Edge protection on both sides keeps wheelchair casters from slipping over the side.⁸

Curb Ramps

Where the accessible route crosses a curb, a curb ramp is required. Running slope is capped at 1:12 and cross slope at 1:48, matching the general ramp rules. Side flares, where provided, cannot exceed 1:10. The curb ramp cannot project into vehicular lanes, parking spaces, or access aisles, and it has to be designed so water doesn’t pool at the transition to the street.⁷

Surfaces, Gratings, and Small Level Changes

Every floor and ground surface along the accessible route must be stable, firm, and slip resistant. Stable means the surface resists movement; firm means it resists deformation under pressure; slip resistant means it gives enough traction for safe travel in typical conditions. Loose gravel, thick sand, and plush carpet all fail. Carpet, where used, must have a pile height of half an inch or less measured to the backing, with level or textured loop, level cut pile, or level cut/uncut pile texture, and a firm pad or backing underneath.⁹

Gratings on the ground surface must have openings no wider than half an inch measured in the direction of travel. Elongated openings, like those in most drainage grates, must be oriented so the long dimension runs perpendicular to the dominant travel direction. That keeps wheelchair casters and cane tips from dropping into the gaps.⁹

Small elevation changes along the route are regulated separately from slope. A vertical change up to one-quarter inch can be left as a square edge. Between one-quarter inch and one-half inch, the change has to be beveled at a slope no steeper than 1:2. Anything taller than one-half inch requires a ramp or curb ramp. Expansion joints, thresholds, transitions between flooring materials, and shifted concrete slabs are where those thresholds get missed. A half-inch lip that looks trivial can stop a front caster cold.¹

Keeping the Route Usable

Building the route correctly is half the obligation. Federal regulations require public accommodations to maintain accessible features in operable working condition at all times, with the only exception being isolated or temporary interruptions for maintenance or repair.¹⁰ A propped-open fire door blocking a corridor, an elevator left unrepaired for weeks, or storage boxes stacked in an accessible aisle each violate that rule.

For public entities under Title II, the maintenance duty explicitly includes keeping pedestrian routes clear of snow and ice. The agency cannot shift that responsibility entirely to adjacent property owners. Local ordinances may create shared obligations, but the agency’s own duty to keep the path of travel open runs year-round and covers debris and work zones as well as weather.

Existing Buildings and Readily Achievable Barrier Removal

New construction and alterations have to meet the full 2010 Standards. Existing buildings that haven’t been altered face a different but still enforceable standard: they must remove architectural barriers wherever doing so is “readily achievable,” meaning the work can be carried out without much difficulty or expense.¹¹ What counts as readily achievable depends on the cost of the removal relative to the business’s financial resources, the type of operation, and the overall impact on the facility.

Many owners assume a building that predates the ADA carries no obligation. That is wrong. If installing a ramp over two entry steps costs a few thousand dollars and the business generates substantial revenue, the removal is almost certainly required. A small independent shop in a building where structural work would run into six figures may satisfy the standard by offering curbside service or another alternative. The obligation is ongoing: as a business grows more profitable, or as the cost of a specific fix drops, work that was once unreasonable can become required.

Religious and Historic Property Boundaries

Two categories fall partly outside these rules. Religious entities, including places of worship and organizations they control, are exempt from ADA Title III altogether, covering both religious and secular activities. If a religious entity rents its space to a non-religious tenant running a place of public accommodation, the tenant is covered even though the landlord is not.¹²

Buildings listed in or eligible for the National Register of Historic Places still have to comply to the maximum extent feasible when altered. Where the State Historic Preservation Officer or the Advisory Council on Historic Preservation determines that full compliance with accessible route, entrance, or restroom requirements would threaten or destroy the building’s historic significance, specific exceptions apply to those elements. Alternatives such as audio-visual materials depicting inaccessible portions of a historic house museum, or relocating programs to accessible spaces, may substitute for physical modifications.⁸

1
ADA.gov. 2010 ADA Standards for Accessible Design
2
U.S. Access Board. Chapter 4: Accessible Routes
3
U.S. Access Board. Chapter 4: Entrances, Doors, and Gates
4
U.S. Access Board. Chapter 3: Clear Floor or Ground Space and Turning Space
5
U.S. Access Board. Chapter 3: Protruding Objects
6
U.S. Access Board. ADA Standards – Chapter 4: Accessible Routes
7
U.S. Access Board. Chapter 4: Ramps and Curb Ramps
8
U.S. Access Board. ADA Accessibility Standards
9
U.S. Access Board. Chapter 3: Floor and Ground Surfaces
10
eCFR. 28 CFR 36.211 – Maintenance of Accessible Features
11
GovInfo. 28 CFR 36.304 – Removal of Barriers
12
ADA.gov. ADA Title III Technical Assistance Manual