Accessibility Guidebook for Outdoor Recreation and Trails

Tread Obstacles on Trails

A tread obstacle is anything that interrupts the evenness of the tread surface. On trails, tread obstacles often occur as a result of ruts, roots, and rocks in the tread surface. Ensure tread obstacles are not more than 2 inches (50 millimeters) high. Where the surface is paved or is built with boards, ensure tread obstacles do not exceed one-half inch (13 millimeters) in height. Height of tread obstacles must be measured vertically from the trail tread surface to the highest point of the obstacle. If a condition for an exception prevents achieving full compliance with the obstacle height requirements, the first general exception allows achieving the requirements to the extent practicable.