23 U.S.C. § 132 — Payments on Federal-aid projects undertaken by a Federal agency

(a) In general. If a federal agency is going to carry out a proposed federal-aid project under an agreement between a state and that agency, the state has two options: (1) it can direct the Secretary to transfer the federal share of project funds straight to the federal agency; or (2) it can deposit money with, or pay, the federal agency itself, in whatever amount is needed to meet the state's obligation under the agreement for the work. (b) Reimbursement. Once the state and Secretary have executed a project agreement as described in subsection (a), the Secretary can use any available funds to reimburse the state for the estimated federal share of the deposit or payment the state made under (a)(2). (c) Recovering and crediting extra funds. If the state was reimbursed more than the federal government's actual pro-rata share of the state's cost — as shown on the state's approved final voucher — that extra amount must be recovered and credited back to the same category of funds it originally came from.