Subsection (o) of section 131 of title 23, United States Code, was added by section 122 of the Federal-Aid Highway Act of 1976 to provide that a state may request an exemption from removal requirements of the Federal-Aid Highway Beautification Act upon a showing that removal of certain signs would work a substantial economic hardship within a specific area. The Department of Transportation will make the application, which is permitted under this provision, to the United States Department of Transportation and will permit directional signs to exist in conformance with any approved exemption which has been granted in conformance with the Federal statute.