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.