; and (2) apply the funding to another grant under this section. (k) Federal share (1) In general The Federal share of the cost of a project for which a grant is made under the Program, as estimated by the Secretary, shall be not more than 80 percent. (2) Additional Federal share The Federal share of the cost of a project carried out by a State using funds provided under this section may be increased by 5 percent if the such 5 percent is used for the mitigation of diesel emissions from construction activities associated with the project. The Administrator of Environmental Protection Agency, in consultation with the Secretary, shall develop guidance for eligible equipment and activities consistent with existing State, local, and nonprofit clean construction guidelines. (l) Administration and oversight costs The Secretary may retain up to one-half of 1 percent of the amounts made available to carry out this section for each fiscal year for the cost of administration and oversight of projects funded under the Program. (m) Authorization and availability of funds (1) Authorization There is authorized to be appropriated from the Freight Trust Fund to carry out this section an amount equal to 50 percent of the receipts of the Freight Trust Fund for each fiscal year beginning in fiscal year 2018. (2) Availability Amounts authorized under paragraph (1) shall be— (A) available for obligation on October 1 of the fiscal year for which they are authorized; and (B) available for obligation until expended. (n) Application of rate requirements The Secretary shall take such action as may be necessary to apply the requirements described under section 113 of title 23, as applicable, to any project receiving funds under this section. (o) Definitions In this section: (1) Designated entity The term designated entity means— (A) a State; (B) a unit of local government; (C) a metropolitan planning organization; (D) a public transportation authority (including a port authority); (E) a tribal government