Table 5.27 – Detectable Warnings
Current Guidelines:  
4.1.3  Accessible Buildings:  New Construction.
Accessible buildings and facilities shall meet the following minimum requirements: . . .

(15)  Detectable warnings shall be provided at locations specified in 4.29.

4.7.7  Detectable Warnings.  A curb ramp shall have a detectable warning complying with 4.29.2.  The detectable warning shall extend the full width and depth of the curb ramp. 

4.29.1  General.  Detectable warnings required by 4.1 and 4.7 shall comply with 4.29.

4.29.2  Detectable Warnings on Walking Surfaces.  Detectable warnings shall consist of  raised truncated domes with a diameter of  nominal 0.9 in (23 mm), a height of nominal 0.2 in (5 mm) and a center-to-center spacing of nominal 2.35 in (60 mm) and shall contrast visually with adjoining surfaces, either light-on-dark, or dark-on-light.  The material used to provide contrast shall be an integral part of the walking surface.  Detectable warnings used on interior surfaces shall differ from adjoining walking surfaces in resiliency or sound-on-cane contact.

4.29.5  Detectable Warnings at Hazardous Vehicular Areas.  If a walk crosses or adjoins a vehicular way, and the walking surfaces are not separated by curbs, railings, or other elements between the pedestrian areas and vehicular areas, the boundary between the areas shall be defined by a continuous detectable warning which is 36 in (915 mm) wide, complying with 4.29.2.

4.29.6  Detectable Warnings at Reflecting Pools.  The edges of reflecting pools shall be protected by railings, walls, curbs, or detectable warnings complying with 4.29.2.

10.3.1  New Construction.  New stations in rapid rail, light rail, commuter rail, intercity bus, intercity rail, high speed rail, and other fixed guideway systems (e.g., automated guideway transit, monorails, etc.) shall comply with the following provisions as applicable: . . .

(8)  Platform edges bordering on a drop-off and not protected by platform screens or guard rails shall have a detectable warning.  Such detectable warnings shall comply with 4.29.2 and shall be 24 inches wide running the full length of the platform drop-off.
Final Revised Guidelines:  
218.2 New and Altered Fixed Guideway Stations.  New and altered stations in rapid rail, light rail, commuter rail, intercity rail, high speed rail, and other fixed guideway systems shall comply with 810.5 through 810.10.

218.3  Key Stations and Existing Intercity Rail Stations.  Key stations and existing intercity rail stations shall comply with 810.5 through 810.10.

810.5  Rail Platforms.  Rail platforms shall comply with 810.5.

810.5.2  Detectable Warnings.  Platform boarding edges not protected by platform screens or guards shall have detectable warnings complying with 705 along the full length of the public use area of the platform.

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.

705.2  Platform Edges.  Detectable warning surfaces at platform boarding edges shall be 24 inches (610 mm) wide and shall extend the full length of the public use areas of the platform.


Model Codes & Standards
IBC 2000:  Section 1108.9 has an equivalent requirement for detectable warnings at transit platform edges.

IBC 2003:  Section 1109.9 has an equivalent requirement for detectable warnings at transit platform edges.

ICC/ANSI A117.1-1998:  Sections 705.1 through 705.3 have similar requirements for detectable warnings characteristics.