36 CFR Part 1191 ABA Accessibility Guidelines, Outdoor Developed Areas - Preamble

F247.2 Existing Trails

Where the original design, function, or purpose of an existing trail is changed and the altered portion of the trail directly connects to a trailhead or another trail that substantially meets the technical requirements for trails in 1017, this section requires the altered portion of the trail to comply with the technical requirements for trails in 1017. Routine or periodic maintenance activities that are performed to return an existing trail to the condition to which the trail was originally designed are not required to comply with the technical requirements for trails in 1017.