36 C.F.R. § 212.50 : Parks, Forests, and Public Property — FOREST SERVICE, DEPARTMENT OF AGRICULTURE — TRAVEL MANAGEMENT — DESIGNATION OF ROADS, TRAILS, AND AREAS FOR MOTOR VEHICLE USE — Purpose, scope, and definitions

(a) Purpose. This subpart provides for a system of National Forest System roads, National Forest System trails, and areas on National Forest System lands that are designated for motor vehicle use. After these roads, trails, and areas are designated, motor vehicle use, including the class of vehicle and time of year, not in accordance with these designations is prohibited by 36 CFR 261.13. Motor vehicle use off designated roads and trails and outside designated areas is prohibited by 36 CFR 261.13.
(b) Scope. The responsible official may incorporate previous administrative decisions regarding travel management made under other authorities, including designations and prohibitions of motor vehicle use, in designating National Forest System roads, National Forest System trails, and areas on National Forest System lands for motor vehicle use under this subpart.
(c) For definitions of terms used in this subpart, refer to §212.1 in subpart A of this part.

36 C.F.R. § 212.50