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Note: This document or portion of document references a state or local code that is stricter than the 2010 ADA Standards requires.

11B-406.5 Common requirements.

Curb ramps and blended transitions shall comply with Section 11B-406.5.

11B-406.5.1 Location.

Curb ramps and the flared sides of curb ramps shall be located so that they do not project into vehicular traffic lanes, parking spaces, or parking access aisles. Curb ramps at marked crossings shall be wholly contained within the markings, excluding any flared sides.

Exception: Diagonal curb ramps shall comply with Section 11B-406.5.9.

11B-406.5.2 Width.

The clear width of curb ramp runs (excluding any flared sides), blended transitions, and turning spaces shall be 48 inches (1219 mm) minimum.

11B-406.5.3 Landings.

Landings shall be provided at the tops of curb ramps and blended transitions. The landing clear length shall be 48 inches (1219 mm) minimum. The landing clear width shall be at least as wide as the curb ramp, excluding any flared sides, or the blended transition leading to the landing. The slope of the landing in all directions shall be 1:48 maximum.

Exception: Parallel curb ramps shall not be required to comply with Section 11B-406.5.3.

DSA icon
Advisory 11B-406.5.3 Landings. A level landing, 48” deep and at least as wide as the curb ramp, is required at the top of a curb ramp. The landing provides an area for users to exit the curb ramp and proceed along the walking surface at the top of the curb ramp.

Some designs have been proposed that reduce or omit the level top landing by providing a curb ramp with flared sides of 1:12 or less. This design is not compliant with the building code and may result in a condition where a wheelchair user cannot safely turn and proceed along the intersecting walk. Section 11B-403.5.1, Exception 3, requires walks and sidewalks to be 48” wide minimum; Section 11B-403.3 requires walks and sidewalks to have a cross-slope of 1:48 or less. In this example, reducing or omitting the top landing of the curb ramp may result in a substandard walk width and/or a walk with a cross-slope in excess of 1:48.◼

Plan view of a perpendicular curb ramp with detectable warnings and a landing at least 48" deep at the top of the curb ramp

FIGURE 11B-406.5.3 ‡‡
LANDINGS AT THE TOP OF CURB RAMPS

11B-406.5.4 Floor or ground surfaces.

Floor or ground surfaces of curb ramps and blended transitions shall comply with Section 11B-405.4.

11B-406.5.5 Wet conditions.

Curb ramps and blended transitions shall comply with Section 11B-405.10.

11B-406.5.6 Grade breaks.

Grade breaks at the top and bottom of curb ramp runs shall be perpendicular to the direction of the ramp run. Grade breaks shall not be permitted on the surface of ramp runs and turning spaces. Surface slopes that meet at grade breaks shall be flush.

11B-406.5.7 Cross slope.

The cross slope of curb ramps and blended transitions shall be 1:48 maximum.

11B-406.5.8 Counter slope.

Counter slopes of adjoining gutters and road surfaces immediately adjacent to and within 24 inches (610 mm) of the curb ramp shall not be steeper than 1:20. The adjacent surfaces at transitions at curb ramps to walks, gutters, and streets shall be at the same level.

In cross section, a curb ramp with a maximum slope of 1:12 adjoins a surface at the bottom that has a maximum counter slope of 1:20

FIGURE 11B-406.5.8
COUNTER SLOPE OF SURFACES ADJACENT TO CURB RAMPS

11B-406.5.9 Clear space at diagonal curb ramps.

The bottom of diagonal curb ramps shall have a clear space 48 inches (1219 mm) minimum outside active traffic lanes of the roadway. Diagonal curb ramps provided at marked crossings shall provide the 48 inches (1219 mm) minimum clear space within the markings.

11B-406.5.10 Diagonal curb ramps.

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.

A plan view of a diagonal curb ramp is shown at a marked crossing. A space 48 inches minimum, measured in the direction of the ramp run, is provided at the bottom of the ramp outside active traffic lanes and within the boundary of the marked pedestrian crossing. Sections of curb 24 inches minimum in length are shown beyond the flared sides and within the marked crossing.

FIGURE 11B-406.5.10 ‡‡
DIAGONAL OR CORNER TYPE CURB RAMPS

11B-406.5.12 Detectable warnings.

Curb ramps and blended transitions shall have detectable warnings complying with Section 11B-705.

U.S. Access Board's Note to Reader:

The Department of Transportation's ADA Standards require detectable warnings on curb ramps:

[ADA Title II - Public Transportation] 406.8 Detectable Warnings. A curb ramp shall have a detectable warning complying with 705. The detectable warning shall extend the full width of the curb ramp (exclusive of flared sides) and shall extend either the full depth of the curb ramp or 24 inches (610 mm) deep minimum measured from the back of the curb on the ramp surface.

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