Truncated Dome vs Detectable Warning: Terminology Guide 2026

Compliance disclaimer: Always verify current requirements with your local jurisdiction. This article reflects 2026-05-07 specifications under ADA Standards 705 and 36 CFR Part 1191.

In a single submittal package you can find both terms used to describe the same yellow panel: "truncated dome" on the architect's plan, "detectable warning" in the specifier's section reference, and sometimes both inside the same paragraph of the building code review letter. Knowing which term belongs where keeps a project moving.

The 60-word direct answer: Truncated dome and detectable warning describe the same ADA product, but they come from different code books. Truncated dome is the geometric term used in ANSI A117.1 and product literature. Detectable warning is the federal regulatory term used in ADA Standards 705 and 36 CFR Part 1191. Use the right term in the right document.

Quick-Answer Comparison Table

Why Are There Two Names for One Product?

The terminology split traces back to the 1990s. The federal Access Board (the agency that writes ADA) chose detectable warning because it describes the function. The product had to be detectable, and it had to warn the user. The geometry was a means to that end.

ANSI A117.1, the model accessibility standard adopted by most state building codes, uses truncated dome because that is the literal shape of the bump. ANSI is a standards-developing body, not a regulator, so it tends toward descriptive language.

The result is a vocabulary split that maps cleanly onto job roles:

• Federal regulators use detectable warning
• State and city building officials use truncated dome more often than not
• Manufacturers, who sell into both worlds, pick the term that wins the search query (which is why their cut sheets often hedge)

When to Use Each Term

The terminology choice matters most in three documents.

Code Review Letters and ADA Audit Reports

Use detectable warning. The agency reviewing the project pulls citations from ADA Standards and 36 CFR Part 1191, both of which use detectable warning exclusively. The right phrase signals that the design team is reading the same source the reviewer is.

Construction Drawings and Spec Sections

Use truncated dome in the drawing callout, with the formal regulatory citation in the spec section. A typical correct callout reads:

12. TRUNCATED DOME PANEL, FED YELLOW, 24" DEEP X RAMP WIDTH, ADA STANDARDS 705.1

The drawing label is what the contractor sees first. Truncated dome lands faster in the field than "detectable warning surface."

Manufacturer Submittals and Cut Sheets

Use whichever the manufacturer uses, and add a single line that maps the manufacturer's product to the regulatory term. For example: "ProDome XR (truncated dome panel) meets ADA Standards 705 detectable warning surface requirements."

That single line resolves the cross-reference for both the contractor and the inspector.

Are Truncated Domes and Tactile Paving the Same?

Tactile paving is a broader umbrella term used internationally. It covers two surfaces: detectable warnings (the dome pattern, used at hazards) and directional indicators (a parallel bar pattern, used to lead pedestrians along a path). Truncated dome refers to the warning version only.

In the United States, ADA Standards 705 only addresses the warning surface. Directional tactile paving is sometimes installed in transit settings under FTA guidance but is not federally required at curb cuts. If you see a parallel-bar tactile in a US transit station, it is a directional surface and not a regulated truncated dome.

How Does Cast-in-Place Compare with Surface-Applied?

Once terminology is sorted, the next question is how the panel attaches. Both cast-in-place and surface-applied systems are detectable warnings under federal regs, both are truncated domes by geometry, and both follow the same ADA Standards 705 dimension rules. They differ only in how they bond to the slab. For the install-method walkthrough, see cast-in-place vs surface-applied truncated dome.

What Did Cojo Run Into in the Field?

In March 2026, Cojo crewed a curb-cut retrofit at a 28,000-square-foot retail strip in north Salem where the city plan reviewer flagged the original spec for using only the term "tactile warning." The original specifier had pulled the phrase from a Canadian product cut sheet. We re-issued the submittal with both terms aligned: "Surface-applied truncated dome panel, federal yellow, meeting ADA Standards 705 detectable warning surface requirements." The plan review cleared inside two business days.

That kind of mismatch is the most common terminology problem we see in Oregon. The product is correct. The paperwork uses a term the reviewer cannot search in their own code book.

If a submittal gets bounced for terminology and the project has a tight timeline, the cost of a re-submittal usually runs:

Industry Baseline Range

Current Market Reality

In 2026, plan-review backlogs in Portland and Salem have stretched the cost of a re-submittal cycle. A bounced detectable-warning callout that adds three business days to a tenant-improvement schedule can swamp the cost of the panels themselves.

Common Terminology Mistakes in Spec Docs

These show up in roughly one in five submittals Cojo reviews on retrofit work:

1. Calling a directional tactile surface a detectable warning. Different product.
2. Specifying ANSI A117.1 dimensions without the ADA Standards 705 cross-reference. State code may accept ANSI; federal compliance review will not.
3. Using "ADA tile" as a generic, then attaching a non-compliant cut sheet. Manufacturer marketing terms are not regulatory terms.
4. Omitting the 70 percent contrast calculation when specifying a custom color. Per ADA 705.2, the color choice is a calculation, not a preference.
5. Citing only "ADA-compliant" without naming a section. Inspectors want section numbers.

Get a Compliant Truncated Dome Install

Cojo installs ADA detectable warning panels (truncated domes) on parking-lot accessible routes, sidewalks, and transit-adjacent platforms across Oregon. Submittal packages from Cojo cross-reference both terminologies and include the ADA Standards 705 citations the reviewer expects. Contact Cojo for a site-specific scope, or browse our striping services.