36 CFR § 4.10 - Travel on park roads and designated routes.
(a) Operating a motor vehicle is prohibited except on park roads, in parking areas and on routes and areas designated for off-road motor vehicle use.
(b) Routes and areas designated for off-road motor vehicle use shall be promulgated as special regulations. The designation of routes and areas shall comply with § 1.5 of this chapter and Executive Order 11644 (3 CFR, 1971-1975 Comp., p. 666). Routes and areas may be designated only in national recreation areas, national seashores, national lakeshores and national preserves.
(c) The following are prohibited:
(1) Operating a motor vehicle not equipped with pneumatic tires, except that a track-laying motor vehicle or a motor vehicle equipped with a similar traction device may be operated on a route designated for these vehicles by the superintendent.
(2) Operating a motor vehicle in a manner that causes unreasonable damage to the surface of a park road or route.
(3) Operating a motor vehicle on a route or area designated for off-road motor vehicle use, from 1/2 hour after sunset to 1/2 hour before sunrise, without activated headlights and taillights that meet the requirements of State law for operation on a State highway.