In addition to its other powers, the Administration, with funds received from the federal government or any federal agency, may: Construct, reconstruct, improve, and maintain the State highway system; and For this purpose, as agreed to by the Administration and any affected railroad company, subject to compliance with § 8-639 of this title: Construct, reconstruct, alter, repair, or relocate any railroad grade separation; and Otherwise eliminate any highway hazard at a railroad grade crossing. All federal funds accepted under this section shall be accepted and spent by the Administration on the terms and conditions that the federal government requires. Except as otherwise provided by federal law, the total cost of any project undertaken with federal funds shall be borne entirely by those funds to the extent that they are available. If federal funds for a project are insufficient or unavailable to pay the total cost of the project, the excess of the total cost over the federal funds received shall be borne as provided by law.