Truncated Domes and the Blind and Visually Impaired

The latest risk for property owners and small businesses is now coming from a handful of Plaintiffs who are, or claim to be, legally blind or visually impaired. We have seen cases filed by Christopher Soldan and Kayla Ryan who are represented by attorney Marty J. Nicholson with Calhoun & Associates law firm. The law is somewhat unsettled in this area.

The ADA laws do provide that a detectable warning is "A standardized surface feature built in or applied to walking surfaces or other elements to warn of hazards on a circulation path." (106.5, 2010 ADA Standards for Accessible Design). It is a unique and standardized feature, intended to function much like a stop sign, and to alert pedestrians who are visually impaired to the presence of a hazard in the line of travel.

Transit platform edges have been required in some form since 1991, but the exact layout has been unclear.

Code sections now provide:

705.1 General. Detectable warnings shall consist of a surface of truncated domes and shall comply with 705.

705.1.1 Dome Size. Truncated domes in a detectable warning surface shall have a base diameter of 0.9 inch (23 mm) minimum and 1.4 inches (36 mm) maximum, a top diameter of 50 percent of the base diameter minimum to 65 percent of the base diameter maximum, and a height of 0.2 inch (5.1 mm).

705.1.2 Dome Spacing. Truncated domes in a detectable warning surface shall have a center-to-center spacing of 1.6 inches (41 mm) minimum and 2.4 inches (61 mm) maximum, and a base-to-base spacing of 0.65 inch (17 mm) minimum, measured between the most adjacent domes on a square grid.

705.1.3 Contrast. Detectable warning surfaces shall contrast visually with adjacent walking surfaces either light-on-dark, or dark-on-light.

You should discuss with a lawyer very knowledgeable in this area what may be required regarding a specific property.