Under the first grandfather clause, the Federal Highway Administration (FHWA) (known as the Bureau of Public Roads prior to 1966) had the authority to determine whether specific grandfather claims would be allowed. Although no formal approval process was established, informal procedures soon evolved. In general, a State seeking to establish grandfather rights would submit copies of the appropriate 1956 statute to the FHWA. The agency would review the claim, and, if it determined that the documentation was ambiguous or otherwise arguable, FHWA would request an attorney general's opinion. Claims that were not legally defensible were rejected.