36 CFR § 5.4 - Commercial passenger-carrying motor vehicles.
(a) The commercial transportation of passengers by motor vehicles except as authorized under a contract or permit from the Secretary or his authorized representative is prohibited in Crater Lake (prohibition is limited to sightseeing tours on the rim drive), Glacier (prohibition does not apply to nonscheduled tours on portions of the park road as defined in § 7.3 of this chapter), Grand Canyon (prohibition does not apply to the north rim or to nonscheduled tours as defined in § 7.4 of this chapter), Grand Teton (prohibition does not apply to those portions of Highways Nos. 26, 89, 187, and 287 commencing at the south boundary of the park and running in a general northerly direction to the east and north boundaries of the park), Mesa Verde (prohibition does not apply to transportation between points within the park and outside points), Denali National Park and Preserve (prohibition does not apply to that portion of the Denali Park road between the Highway 3 junction and the Denali Park Railroad Depot), Sequoia-Kings Canyon, Yellowstone (prohibition does not apply to nonscheduled tours as defined in § 7.13 of this chapter, nor to that portion of U.S. Highway 191 traversing the northwest corner of the park) and Yosemite National Parks. The following principles will govern the interpretation and enforcement of the section:
(1) Transportation is commercial if it is operated primarily as a business activity or for profit of the operator, or if any person or organization may receive a profit, commission, fee, brokerage or other compensation for organizing, advertising, promoting, soliciting or selling the trip or tour of which such transportation is a part.
(2) Transportation is commercial if payment therefor is made directly or indirectly to the operator: Provided, That bona fide sharing of actual expenses will not be deemed a payment.
(3) Transportation by a motor vehicle licensed as a commercial vehicle, or of commercial type, will be presumed to be commercial unless otherwise established to the satisfaction of the Superintendent or his authorized representative.
(4) Transportation will not be deemed commercial for the sole reason that the motor vehicle is chartered or rented in good faith to the operator, by the owner, for general use at a charge based upon time or mileage or both. Nothing in this section is intended to prohibit the operation of pleasure type automobiles rented without a driver on the normal terms from the owner.
(5) Subject to the provision of paragraph (a)(1) of this section, transportation is not commercial if it is a part of a trip or tour initiated, organized, and directed by an established bona fide school or college, institution, society or other organization, as a nonprofit activity of such organization, and if all passengers are students, faculty, members, or employees of such organization, or otherwise connected therewith, provided that credentials are presented at the park entrance from the head of such institution or organization indicating the trip is in accordance with the provisions stipulated herein. Clubs or associations having as a principal purpose the arranging of tours, trips, or transportation for their members will not qualify for admission into the above-named parks under the provision of this paragraph.
(6) As used in this section, “owner” means the person or organization having legal title, or all the incidents of ownership other than legal title, of a motor vehicle by which passengers may be transported, and includes a registered owner or a purchaser under a conditional sales contract. “Operator” means the person, organization, or group that arranges for the transportation, assumes responsibility for financial risk and management, and determines who shall be transported upon what terms, conditions, or charges. The operator may be the owner, but need not be.
(b) Passenger-carrying motor vehicles, otherwise admissible, that are so large as to require special escort in order to proceed safely over park roads, or which in the judgment of the Superintendent are beyond the carrying capacity or safety factor of the roads, will not be permitted in the parks, except that, where they may satisfactorily enter and travel to park headquarters they may be parked there during the period of stay.