accessibility standards for Federal outdoor developed areas 27 Resting Intervals  Resting intervals are level areas that provide an opportunity for people to stop after a steep segment and recover before continuing on. Resting intervals are required between trail segments any time the running slope exceeds 1:20 (5 percent). Resting intervals may be provided within the trail tread or adjacent to the trail tread. When the resting interval is within the trail tread, it must be at least 60 inches long and at least as wide as the widest segment of the adjacent trail tread. When the resting interval is adjacent to the trail, it must be at least 60 inches long and 36 inches wide. A turning space that complies with section 304.2.3 of the ABA Standards must be provided. The vertical alignment of the trail tread, turning space, and resting interval must be nominally planar so that all the wheels of a mobility device touch the ground when turning into and out of the resting interval. When the surface of the resting interval is constructed of concrete, asphalt, or boards, the slope of the resting interval must be no steeper than 1:48 (2 per- cent) in any direction. When the surface of the resting interval is constructed of materials other than concrete, asphalt, or boards, slopes no steeper than 1:20 (5 percent) are allowed when necessary for drainage.