Outdoor Developed Areas: A Summary of Accessibility Standards for Federal Outdoor Developed Areas

Surface and Slope [1015.5 and 1015.6]

The surface of clear ground spaces and turning spaces must be firm and stable. Additional information on firm and stable surfaces is provided in the trails section of this guide.

When the surface of clear ground spaces and turning spaces is constructed of asphalt, concrete, or boards, the slope of the surface must be no steeper than 1:48 (2 percent) in any direction. When the surface is constructed of materials other than asphalt, concrete, or boards, slopes no steeper than 1:20 (5 percent) are allowed when necessary for drainage.