36 C.F.R. § 71.5
(b) The Golden Eagle Passport shall admit the permittee and any persons accompany him in a single, private, noncommercial vehicle, or alternatively, the permittee and his spouse, children, and parents accompanying him where entry to the area is by any means other than private, noncommercial vehicle, to Designated Entrance Fee Areas. Golden Eagle Passport coverage does not include a permittee and his spouse, children, or parents entering a Designated Entrance Fee Area in two separate, private, noncommercial vehicles. In this case, only the vehicle with the permittee shall be covered by the Passport. The persons in the second vehicle shall be subject to the single-visit entrance fee requirement.