Notwithstanding any other provision of law, where the Service or an entity under a service contract, cooperative agreement, or other contractual agreement with the Service provides transportation to all or a portion of any System unit, the Secretary may impose a reasonable and appropriate charge to the public for the use of the transportation services in addition to any admission fee required to be paid. Collection of the transportation and admission fees may occur at the transportation staging area or any other reasonably convenient location determined by the Secretary. The Secretary may enter into agreements, with public or private entities that qualify to the Secretary's satisfaction, to collect the transportation and admission fee. Transportation fees collected pursuant to this section shall be retained by the System unit at which the transportation fee was collected, and the amount retained shall be expended only for costs associated with the transportation systems at the System unit where the charge was imposed.