Following years of ambiguity and misinterpretation, these and similar provisions relating to “clear” spaces—such as clear floor spaces, maneuvering clearances, and so forth—are now expressly defined as prohibiting detectable warnings. As part of this revision, the former exception for 1:48 maximum slopes is relocated to the technical requirement itself.
11B-404.2.4.4 Floor or ground surface. Floor or ground surface within required maneuvering clearances shall comply with Section 11B-302. Changes in level, slopes exceeding 1:48, and detectable warnings are shall not be permitted.
11B-405.7.1 Slope. Landings shall comply with Section 11B-302. Changes in level, slopes exceeding 1:48, and detectable warnings are shall not be permitted.
Exception: Slopes not steeper than 1:48 shall be permitted. Reserved.
11B-404.2.9 Door and gate opening force. …
The reference to Section 11B-304 (turning space) was a “drafting error” (per DSA), and the inclusion of Section 11B-309 requires compliance with Sections 11B-305 and 11B-308 by reference.
11B-406.3 Parallel curb ramps. Parallel curb ramps shall comply with Sections 11B-406.3 and 11B-406.5. A parallel curb ramp may be provided with one sloping segment or two opposing sloping segments.
Current provisions do not specifically address parallel curb ramps with only one sloping segment. This revision expressly permits parallel curb ramps with one or two opposed sloping segments.
11B-406.5.10 Diagonal curb ramps. Diagonal or corner type curb ramps are perpendicular or parallel curb ramps that are oriented diagonally at an intersection. Diagonal or corner type curb ramps with returned curbs or other well-defined edges shall have the edges parallel to the direction of pedestrian flow. Diagonal curb ramps with flared sides shall have a segment of curb 24 inches (610 mm) long minimum located on each side of the curb ramp and within the marked crossing.
The code figure illustrates a perpendicular curb ramp, but the text of the code does not prohibit the use of a parallel curb ramp in a similar configuration. This revision expressly permits such design.