Accessibility Guidebook for Outdoor Recreation and Trails

Openings in Trail Surfaces

Openings are gaps in the surface of a trail. Gaps include slots in a drainage grate and spaces between the planks on a puncheon, bridge, or boardwalk. Openings that are big enough to allow wheels, cane or crutch tips, or shoe heels to drop through or get stuck are hazards that shouldn't exist in pedestrian routes. Openings up to a half of an inch (13 millimeters) across are permitted in trail surfaces. Place elongated openings more than a quarter of an inch wide with the long dimension perpendicular or diagonal to the primary direction of travel (figure 138).

Figure 138—The requirements for openings that are perpendicular to the direction of travel on trail surfaces, such as boardwalk decking.

If there is a condition for an exception, openings less than three-fourths of an inch (19 millimeters) across are allowed. This deviation allows the use of boardwalk decking that needs more than ½-inch (13-millimeter) -wide spacing between the planks to permit expansion and to allow water to drain. If even the three-fourths of an inch deviation is not enough, General Exception 1 allows achieving trail surface opening requirements to the extent practicable if a condition for an exception is present.