Build USA Infrastructure Act This bill addresses highway infrastructure funding. The bill requires, for the five-year period beginning on October 1, 2020, the deposit of the first $21.4 billion of revenues collected by the U.S. Customs and Border Protection into the Highway Trust Fund. A state may enter into an agreement with the Federal Highway Administration (FHWA), for a period of three years or longer, under which it agrees to opt out of receiving at least 60% of funds out of the Highway Trust Fund that the state may receive during each year of the agreement for federal-aid highway activities under the national highway performance program and the surface transportation block grant program; accept from the FHWA funds equal to 90% of the amount the state opted out of; and use those funds to carry out core infrastructure projects in accordance with provisions that authorize the state to determine whether it is in compliance with certain federal project requirements, including the use of steel, iron, and manufactured products produced in the United States. The amount of the opt out does not include amounts required to be set aside, penalties, or amounts required to be suballocated to areas based on population.