2013 Forest Service Trail Accessibility Guidelines (FSTAG)

7.4.2 Clear Tread Width.

The clear tread width of the trail shall be at least 36 inches (915 mm).

EXCEPTION:  Where a condition for an exception prevents achieving the required width, the clear tread width may be reduced to 32 inches (815 mm) minimum. If the condition for an exception prevents achieving the reduced width of 32 inches, comply to the extent practicable.