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Detectable Warnings: Codes

Kerwin Lee, AIA

Under the current 2016 California Building Code (CBC), the requirements for detectable warnings continue to be present. This is in light of the 2010 Standards for the Americans with Disabilities Act (ADA) having suspended the requirements and proposed guidelines for “public right-of-ways,” which limits the use of warnings. The state, with support from the disabled community, feels it is something that should continue. The need for this element continues to be debated. But that’s not what this article is about.

The ADA may bring back this requirement under the regulations for public right-of ways, which has written proposed guidelines, issued back in 2011.  There was a public comments period that finalized in 2017.  For the proposed guidelines to become effective, the Department of Justice (DOJ) and Department of Transportation (DOT) need to formally adopt document. This has not happened yet.

Section 11B-705.1.2 Locations: The 2016 CBC requires detectable warnings at platform edges, curb ramps, islands or cut-through medians, bus stops, hazardous vehicular areas, reflecting pools and track crossings. Section 11B-705.1.2.5 states the following:

Hazardous Vehicular Area:  detectable warnings at hazardous vehicular areas shall be 36 inches in width.” 

The problem with this is there is no definition of what a “hazardous vehicular area” is. Is it a crosswalk on the street, a walkway entering a parking lot, or a driveway curb cut across a sidewalk?

UCSB campus where a bike path and cross walk intersect. Bicycles have the right-of-way on the campus.

We still have the criteria of contrast between the detectable warnings and adjacent surface, Section 11B-705.1.1.3. The formula for determining contrast is in the code.  The code and federal standard requires a minimum 70% difference.  That is a 4:1 reflectance difference.  The requirement for the use of “yellow” has been removed from the code.

Take note of the exception in Section 11B-705.1.1.3 under “contrast:”

“Exception: where the detectable warning surface does not provide a 70 percent minimum contrast with adjacent walking surfaces, a 1 inch wide minimum visually contrasting surface shall separate the detectable warning from adjacent walking surface. The visually contrasting surface shall contrast with both the detectable warning and adjacent walking surface either light-on dark, or dark-on-light.”

If the code language is so vague and ambiguous how does one comply?

My recommendation: the only way to comply without much question is to install detectable warnings everywhere and make them yellow. Functionally and design-wise, that is not the only way to comply. These requirements are meant to assist persons with low-vision, not just the blind.  I do believe that the concept and application of “contrast” allows some flexibility. The contrast issue becomes a problem where designers try and make the truncated domes disappear instead of being very visible to demarcate a boundary for visually impaired persons. Use common sense and good design to comply with the intent of the code.