michaelellars.com
Michael Ellars, AIA, APX, CSI, CCCA, CDT, LEED AP, ADAC, CASp
michaelellars.com
Michael Ellars, AIA, APX, CSI, CCCA, CDT, LEED AP, ADAC, CASp
11B-705.1.1.3 Color and contrast. Detectable warning surfaces at transit boarding platform edges, bus stops, hazardous vehicular areas, reflecting pools, and track crossings shall comply with Section 11B-705.1.1.3.1. Detectable warnings at other locations shall comply with either Section 11B-705.1.1.3.1 or Section 11B-705.1.1.3.2. The material used to provide visual contrast shall be an integral part of the surface.
Exceptions:
Starting July 1, 2021, all new detectable warnings must be yellow. Previous allowances for contrasting colors at certain locations have been rescinded, though technically those provisions remain as exceptions for existing installations of detectable warnings. DSA quotes the following research to justify this change: Jenness, J. and Singer, J. (May 24, 2006). Visual Detection of Detectable Warning Materials by Pedestrians with Visual Impairments, Final Report, (Task Order 18 under Project DTFH61-01-C-00049). Westat, Rockville, MD. Federal Highway Administration, Washington, DC. “The general conclusion from research agrees that a standardized color scheme is needed for single-color detectable warnings and that federal yellow is the best choice.”
11B-705.1.1.3.1 Detectable warning surfaces shall be yellow and approximate FS 33538 of Federal Standard 595C SAE AMS-STD-595A.
Federal Standard 595C has been discontinued and replaced by private industry standard SAE AMS-STD-595A, which fortunately utilizes the same color numbers. Interestingly, this revision has only been made to the yellow color specified for detectable warning surfaces, not for the yellow color specified for directional textures or the blue color specified for various accessible striping and sign elements.
From the DSA Initial Statement of Reasons: “This change reformats Section 11B-705.1.2.2 to present detectable warnings requirements separately for perpendicular and parallel curb ramps. Revised detectable warning requirements are also provided for parallel curb ramps with one entrance/exit point (i.e. transition from the turning space to the gutter, street or highway) and those with two entrance/exit points – as may be found in parking lots where a median has accessible parking on both sides of an island. The amendment language requires the turning space to include a 36″ minimum width passage without detectable warnings so pedestrians may travel through the turning space without passing over the detectable warnings. This provision responds to numerous comments from wheelchair users who experience pain when travelling over extended lengths of detectable warnings.”
11B-705.1.2.2 Curb ramps. Detectable warnings at curb ramps shall comply with Section 11B-705.1.2.2.
11B-705.1.2.2.1 Perpendicular curb ramps. Detectable warnings at curb ramps shall extend 36 inches (914 mm) in the direction of travel. Detectable warnings shall extend the full width of the ramp run less 2 inches (51 mm) maximum on each side, excluding any flared sides. Detectable warnings shall be locatd so the edge nearest the curb is 6 inches (152 mm) minimum and 8 inches (203 mm) maximum from the demarcation line at the face of the curb marking the transition between the curb and the gutter, street or highway.
Exception: On parallel curb ramps, detectable warnings shall be placed on the turning space at the flush transition between the street and sidewalk. Detectable warnings shall extend the full width of the turning space at the flush transition between the street and the sidewalk less 2 inches (51 mm) maximum on each side.
11B-705.1.2.2.2 Parallel curb ramps. Detectable warnings at parallel curb ramps shall be located so the edge nearest the curb is 6 inches (152 mm) minimum and 8 inches (203 mm) maximum from the from the demarcation line at the face of the curb between the curb and the gutter, street or highway. Detectable warnings shall extend the full width of the turning space at the demarcation line between the street and the sidewalk less 2 inches (51 mm) maximum on each side.
Figure 11B-705.1.2.2.2
Parallel Curb Ramps
11B-705.1.2.2.2.1 One entrance/exit point. Where the turning space has one entrance/exit point other than the sloped ramp segments, detectable warnings shall be 36 inches (914 mm) deep, as measured perpendicular to the curb, and the turning space shall provide a minimum 36 inches (914 mm) wide portion without detectable warnings to allow pedestrian travel in the direction of the sidewalk without travelling over the detectable warnings.
Exceptions:
11B-705.1.2.2.2.2 Two entrance/exit points. Where the turning space has two entrance/exit points other than the sloped ramp segments, detectable warnings shall be 36 inches (914 mm) deep at both entrance/exit points, as measured perpendicular to the curb, and the turning space shall provide a minimum 36 inches (914 mm) wide portion without detectable warnings to allow pedestrian travel in the direction of the sidewalk without travelling over the detectable warnings.
Exceptions:
11B-705.1.2.5 Hazardous vehicular areas Blended transitions. Detectable warnings at hazardous vehicular areas blended transitions shall be 36 inches (914 mm) in width.
This revision completes the changes made to Section 11B-247.1.2.5 and the addition of Section 11B-250 in Chapter 11B, Division 2.