The width, length and surface of the trail are important factors to determine the grading, in addition to natural obstacles such as rocks, ridges, holes, logs and drop-offs.
The grading system is based on the physical attributes that are present during the course and the challenges, rather than the effort and fitness that is necessary by the walker.
Rather, trail distance should be posted on signs in addition to the difficulty symbol.
[4] Australia's trail rating system evaluates a path's difficulty level based on various criteria, such as: experience needed, steps, slopes, path quality and signage.
Here is the standard grading system:[7] Montreal features five levels:[8] Ireland has a set of five classifications for trails:[9] New Zealand national parks features four grades:[b] The United Kingdom has three grades in their classification system, which are:[11][c] Arizona's trail ratings are as follows:[12] In California, there are three different ratings according to the California Department of Parks & Recreation:[13]