Accessibility Guidebook for Outdoor Recreation and Trails

Clear Tread Width and Passing Spaces for Outdoor Recreation Access Routes

Clear tread width means the width of the traveled surface on the ground and also above the ground between obstacles (figure 40). The minimum clear tread width of an outdoor recreation access route is 36 inches (915 millimeters), which is wide enough to allow unobstructed passage by a wheelchair. When a condition for an exception exists, such as where an outdoor recreation access route must be routed between two large boulders that can't be removed, then the clear tread width may be reduced to not less than 32 inches (815 millimeters) or the maximum width that can be achieved.

Figure 40—The clear tread width is the unobstructed width of the traveling surface.

All outdoor recreation access routes in a recreation site don't necessarily have to be the same width. Consider the number of people who will use the route at the same time and how they will want to use it—single file or walking and talking side by side—and design accordingly. For example, a 60-inch (1,525-millimeter) -wide main route may be designed to connect a group of campsites to important constructed features, such as a rustic outdoor amphitheater, toilet buildings, or water hydrants. Secondary routes, such as a spur from the main route to a quiet, intimate path along a stream, may be only 36 inches (915 millimeters) wide.

Two people using wheelchairs need a 60-inch (1,525-millimeter) -clear tread width to pass comfortably and safely on an outdoor recreation access route. However, this width isn't always appropriate or required. Where the clear tread width of a route is less than 60 inches (1,525 millimeters), passing spaces are required at least every 200 feet (61 meters). Passing spaces must be at least 60 inches (1,525 millimeters) wide (including the route width) by 60 inches (1,525 millimeters) long (figure 41).

Figure 41—Minimum required dimensions for a passing space for an outdoor recreation access route or a beach access route.

Another option allows a T-intersection of two outdoor recreation access routes or other walking surfaces to be a passing space (figure 42) provided that the arms and stem of the T-shaped space extend at least 48 inches (1,220 millimeters) beyond the intersection. Either configuration would provide enough room for a person to move to the side and let an oncoming person pass along the route. The cross slope of a passing space must not exceed 1:33 (3 percent). Where the surface is paved or is built with boards, the slope must not be steeper than 1:48 (2 percent) in any direction.

Figure 42—A T-intersection may be used as a passing space on an outdoor recreation access route or a beach access route if it has dimensions as shown, or larger.