July 10, 2026·8 min read

ADA Accessibility Checklist for Site Design: A Field Guide

A practical ADA accessibility checklist for site design covering slopes, routes, parking, and details that get missed during CA. Built for landscape architects.

ADA compliance failures don't usually happen because a designer didn't know the rules. They happen because the rules live in your head, the drawings are produced under deadline pressure, and nobody built a systematic review into the project workflow. This article gives you a working ADA accessibility checklist for site design organized by phase, with the specific numbers that matter and the details that actually get missed.

Why Site Accessibility Fails in the Field

Most ADA violations on landscape architecture projects aren't egregious. They're 2% cross-slopes instead of 1.9%, a curb ramp that's 59 inches wide instead of 60, a detectable warning surface installed 6 inches from the edge instead of the required flush placement. These are the things that survive design review, survive plan check, and get built wrong anyway.

The 2010 ADA Standards for Accessible Design (specifically Chapter 4, which covers accessible routes) is the governing document for most site work on federally funded or public-accommodation projects. State codes like CBC Chapter 11B in California are often more stringent and supersede the federal standard. Know which applies before you start drawing.

The failure pattern I've seen repeatedly: the accessible route gets designed correctly in schematic, then gets compromised during grading coordination because the civil engineer adjusted spot elevations without flagging the impact on cross-slope. Nobody catches it until the contractor pours concrete.

The Accessible Route: Non-Negotiable Numbers

The accessible route is the spine of your ADA compliance. Every element branches off it. Get these numbers into your drawing notes and verify them at every phase.

Running slope: Maximum 1:20 (5%) without being classified as a ramp. If you're exceeding that, you need handrails, edge protection, and landings at the top and bottom.

Cross slope: Maximum 1:48 (2.08%). This is where projects fail most often. A 2% cross-slope sounds easy to achieve. In practice, grading to 2% across a 20-foot-wide plaza while managing drainage requires careful coordination. Design to 1.5% and give yourself tolerance.

Clear width: Minimum 44 inches for accessible routes with passing spaces. If you're designing a route that two wheelchair users need to pass each other on, you need 60 inches minimum or a 60×60-inch passing space every 200 feet.

Surface: Firm, stable, slip-resistant. Decomposed granite fails this test in most conditions. Stabilized DG with a binder can work if it's specified correctly and maintained — but I've seen it fail within one wet season and create liability exposure.

Landings and Level Changes

Any door, gate, or change in direction on an accessible route needs a landing. Minimum 60×60 inches at doors, 36×36 inches at turns. These get squeezed constantly in tight urban sites. Draw them explicitly in plan. If you're not dimensioning landings in your CDs, they will get built wrong.

Vertical changes up to ¼ inch are permitted without treatment. Changes between ¼ and ½ inch require a beveled edge at 1:2 slope. Anything over ½ inch is a ramp.

Ramps: Where the Details Live

Ramp design looks simple until you get into the details. The 2010 ADA Standards (Section 405) require:

Maximum running slope: 1:12 (8.33%)
Maximum rise per run: 30 inches
Minimum clear width: 36 inches between handrails
Landing at top and bottom: minimum 60 inches in direction of travel
Edge protection: curb, wall, or rail — minimum 4 inches high if using a curb

Handrails are required on both sides of ramps with a rise greater than 6 inches. Rail height: 34–38 inches above ramp surface. The top rail must extend 12 inches horizontally beyond the top landing and extend to the bottom of the ramp slope plus 12 inches at the bottom. These extensions get omitted constantly.

Graspable handrails have specific cross-section requirements. A circular section must be 1¼ to 2 inches in diameter. Non-circular sections must have a perimeter of 4 to 6¼ inches with a maximum cross-section dimension of 2¼ inches. Specify this in the drawings, not just in the spec.

Curb Ramps and Detectable Warning Surfaces

Curb ramps are one of the highest-risk items on any streetscape or public plaza project. The 2010 Standards (Section 406) combined with PROWAG (Public Rights-of-Way Accessibility Guidelines) govern most public ROW work. PROWAG is not yet formally adopted as an ADA standard but is used by FHWA and most transportation agencies — confirm which standard your client's jurisdiction enforces.

Detectable warning surfaces must be:

Truncated dome pattern, 0.9-inch center-to-center spacing, 0.2-inch height
24 inches deep in the direction of travel, full width of the curb ramp
Contrast visually with the surrounding surface (light-on-dark or dark-on-light)
Placed flush with the walking surface — any lip or gap creates a trip hazard

The most common installation error: the contractor sets the detectable warning panel before the final paving lift, creating a ¼-inch lip. Write it into your spec (Section 32 17 23 is the typical CSI location for pavement markings and surface treatments) and call it out in your CA punch list.

Curb ramp width minimum is 36 inches, exclusive of flares. Flares are not part of the accessible route. The running slope of a curb ramp can match the street grade up to 1:10 (10%) in alterations where space is constrained.

Parking: Accessible Stall Requirements

Total Parking Spaces	Required Accessible Spaces	Required Van-Accessible
1–25	1	1
26–50	2	1
51–75	3	1
76–100	4	1
101–150	5	2
151–200	6	2

Van-accessible stalls require a 98-inch vertical clearance (to accommodate lift-equipped vehicles) and an 8-foot-wide access aisle rather than the standard 5-foot aisle. The access aisle must connect to the accessible route without crossing traffic lanes.

One thing that gets missed: the accessible route from the parking stall to the building entrance must be on an accessible surface. A gravel strip between the pavement edge and the sidewalk is not compliant. Design the connection explicitly.

Site Amenities: Picnic Tables, Seating, and Drinking Fountains

These are often afterthoughts in site design and a reliable source of post-construction corrections.

Picnic tables: At least 20% of fixed tables must be accessible, with a minimum of one. Accessible tables need knee clearance of 27 inches high, 30 inches wide, 19 inches deep. The surface height should be 28–34 inches. The accessible table must connect to the accessible route.

Drinking fountains: Where a single drinking fountain is provided, it must serve both ambulatory users (spout height 38–43 inches) and wheelchair users (spout height max 36 inches, knee clearance below). This typically means a hi-lo fountain unit. Specify the model number in your drawings — don't leave it to the contractor.

Benches: If a bench is provided in a space, at least one must have a clear floor space of 30×48 inches adjacent to it. Back support and armrests are not required by ADA but are required by some state codes.

Phase-by-Phase Review Triggers

ADA review shouldn't happen only at the end of CDs. Build review gates into your workflow:

Schematic Design: Confirm the accessible route exists and connects all required elements. Check that grades allow compliance before the design gets locked in.

Design Development: Verify spot elevations at key nodes — ramp landings, plaza entries, accessible parking connections. Coordinate with civil on grading plan.

Construction Documents: Dimension all landings explicitly. Confirm handrail extensions are drawn. Check detectable warning surface notes against spec section. Verify parking count triggers the right accessible stall ratio.

Construction Administration: Add accessible route cross-slopes and ramp slopes to your site observation checklist. Measure them. Bring a digital level. Don't rely on the contractor's word that it's "close enough."

Common Mistakes Firms Make

1. Designing cross-slopes at exactly 2%. That gives you zero tolerance. By the time concrete is poured and finished, you're at 2.2% and out of compliance. Design to 1.5% and build in the buffer.

2. Leaving detectable warning surface placement to the contractor. This needs to be detailed in the drawings — elevation, relationship to finish grade, and the requirement for flush installation.

3. Forgetting handrail extensions. The 12-inch horizontal extensions at the top and the sloped extension at the bottom are consistently omitted from drawings and consistently missing in the field.

4. Not coordinating accessible routes through the grading plan. The civil engineer is moving spot elevations in DD and CD phases. If you're not reviewing their grading plan against your accessible route, you will get cross-slope violations.

5. Using the wrong standard. Federal ADA, CBC 11B, PROWAG, and local amendments don't always agree. Defaulting to the federal standard on a California public project will leave you short of compliance.

6. Skipping the accessible amenity connection. The accessible route gets drawn to the building entrance and stops. The picnic table, drinking fountain, and bench 30 feet away are on an inaccessible grass surface with no paved connection.

How Phasewise Handles This

Phasewise lets you build phase-specific task lists with required sign-offs, which is where ADA review gates belong — not in a separate spreadsheet nobody opens. The checklist and phase tracking features mean your DD and CD reviews can include explicit accessibility verification steps that are tied to the project timeline, not floating in someone's email. When a task is flagged incomplete, it doesn't move forward without a resolution logged.