Truncated Domes
Truncated Dome Color Selection and Contrast (2026 Guide)
Cojo
May 7, 2026
7 min read
Truncated dome color is not a design choice — it is a federal accessibility requirement. ADA Standards 705.2 require detectable warning surfaces to contrast 70 percent or more against the adjacent walking surface, light-on-dark or dark-on-light. Picking the wrong color tone, or pairing a yellow dome against a yellow-tinted concrete, can fail an inspection even when every dome dimension meets 705.1. This guide walks Light Reflectance Value math, the three industry-standard color choices, and the contrast-failure patterns Cojo crews see on Oregon retrofit jobs.
For dimensional spec, see ADA 705.1 dimensions. For the full contrast-rule deep dive, see ADA 705.2 color contrast.
> Compliance disclaimer: Always verify current detectable warning requirements with your local jurisdiction. This article reflects 2026 federal ADA Standards (28 CFR Part 36, Appendix B) and ADA Accessibility Guidelines 705.2.
ADA Standards 705.2 Color says: "Detectable warnings shall contrast visually with adjacent walking surfaces either light-on-dark, or dark-on-light." The U.S. Access Board's advisory note to 705.2 references the recommended 70 percent contrast threshold from older transit-platform research, even though the regulatory text itself does not bind a number. Most state and federal inspectors enforce the 70 percent guidance as a hard floor.
The math behind the threshold is Light Reflectance Value (LRV) — a 0-to-100 scale where 0 is total light absorption (theoretical pure black) and 100 is total reflection (theoretical pure white). The contrast formula is:
Contrast Percent = ((LRV brighter - LRV darker) / LRV brighter) × 100
A safety yellow dome at LRV 75 against a gray sidewalk at LRV 30 gives a contrast of (75 - 30) / 75 × 100 = 60 percent. That fails. The same yellow against a dark gray sidewalk at LRV 18 gives (75 - 18) / 75 × 100 = 76 percent. That passes.
A surface that looks visually distinct can still fail the math. Brick red domes look obviously different from gray concrete — but if the concrete is freshly poured and sun-bleached gray (LRV 35) and the dome is faded brick red (LRV 18), the contrast is only (35 - 18) / 35 × 100 = 49 percent. Cojo runs an LRV check on every retrofit job before the panel order is placed.
Safety yellow is the dominant choice for outdoor parking-lot, sidewalk, and transit-platform installs because:
Safety yellow is the default Cojo orders unless the adjacent walking surface is itself light-colored (white-stained concrete, polished granite, light pavers).
Brick red is the historical choice for transit platforms and indoor terminal applications. LRV runs 12 to 18, which gives strong contrast against light walking surfaces. Best fit for:
Brick red domes against typical gray sidewalk concrete frequently fail the 70 percent threshold because the sidewalk LRV is too close to the dome LRV. Always run the LRV math before specifying.
Three "yellows" appear in catalogs and they are not interchangeable:
| Color | RAL | LRV (typical) | Use case |
|---|---|---|---|
| Safety yellow | RAL 1023 | 72 to 78 | Default ADA dome color |
| Federal yellow | RAL 1004 | 60 to 68 | Older spec, less common today |
| Caterpillar yellow | RAL 1007 | 65 to 72 | Industrial equipment, not ADA-rated |
LRV calculators are free and the inputs are simple — you need either a paint-chip LRV value or a quick photometric reading.
Most ADA-rated panel suppliers publish dome LRV in the product data sheet. For walking surfaces, paint and concrete suppliers publish LRV for sealers, stains, and color-conditioned concrete. Subtract the lower from the higher and divide by the higher.
A handheld luminance meter ($75 to $200) can sample the walking surface in cd/m² and convert to LRV against a reference white card. This is the method Cojo uses for retrofit jobs where the existing concrete has weathered to an unknown LRV.
Apps like Spectrolite or BenjaminMoore Color Capture generate an estimated LRV from a smartphone photo. Accuracy is +/- 5 LRV points — fine for a first-pass screen, not for a final compliance decision.
Industry Baseline Range
| Item | Range |
|---|---|
| Standard safety yellow composite panel | $180 to $320 |
| Premium UV-stable safety yellow | $260 to $420 |
| Brick red composite panel | $200 to $360 |
| Custom-color composite (federal yellow, blue) | $320 to $560 |
| LRV pre-spec consultation | $0 to $250 (often included) |
UV-stable colorant pricing rose 14 percent through 2025 because pigment supply for outdoor-rated yellows tightened. Brick red and safety yellow remain the lowest-cost compliant options. Custom RAL colors carry an order-volume premium and 4 to 6 week lead times. For a same-week install, plan on safety yellow.
This is the most common LRV failure pattern. Sun-faded asphalt looks gray but its LRV at 6 to 8 will pair with brick red (LRV 12 to 18) at only 50 percent contrast — failing 705.2. Tinted concrete in the safety-yellow family can drop a yellow dome's contrast below 30 percent.
When the walking surface is yellow-tinted, two paths work:
The decision is project-economics — staining 20 sq ft of walking surface around a new curb cut runs $80 to $200 in product cost. Switching dome color carries no premium for safety yellow vs brick red but may add $40 to $140 per panel for a custom RAL.
Color is independent of dimensions — a safety yellow dome and a brick red dome both come in the same 0.9 to 1.4 inch base diameter spec per ADA 705.1. The selection decision is purely the LRV pair against the adjacent walking surface. See ADA 705.1 dimensions for the dimensional rules.
On a 2026 retrofit at the University of Oregon's south-campus parking-lot path, Cojo replaced 6 surface-applied panels that had failed an annual ADA audit. The original panels were brick red against a stained concrete walkway with an LRV of 22 — the contrast worked at install in 2018 but the brick red faded to LRV 14 over 8 years, dropping contrast below 50 percent. Cojo specified UV-stable safety yellow (LRV 76) on the same walking surface — contrast jumped to 71 percent on day one of the retrofit and tracks 65 percent or better at the 5-year warranty horizon. Total panel material was $1,440 across the 6 panels.
| Walking surface | Recommended dome color | LRV pair (typical) | Contrast |
|---|---|---|---|
| Standard gray sidewalk | Safety yellow | 30 / 75 | 60% (re-check) |
| Dark gray asphalt | Safety yellow | 8 / 75 | 89% |
| Light stamped concrete | Brick red | 60 / 15 | 75% |
| Polished terrazzo | Brick red | 70 / 15 | 79% |
| Yellow-tinted pavers | Brick red on stained sub-surface | varies | site-specific |
Cojo specifies and installs ADA-compliant truncated dome panels in safety yellow, brick red, and custom RAL colors with LRV verification on every job. Contact Cojo to schedule an ADA path-of-travel audit, or see our Portland truncated dome installation page for service-area details.
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