Outdoor advertising is prohibited along many nationally designated byways and state designated byways with the class or road designation Federal Aid Primary (FAP) or National Highway System (NHS).

Pursuant to federal law at 23 U.S.C. §131, if a state has a state scenic byway program, the State may not allow the erection of new signs not in conformance with 23 U.S.C. §131 along any scenic byway that was on the Federal Aid Primary (FAP) in 1991 or is on the National Highway System (NHS) today.

To determine whether a road is on the FAP or on the NHS, select the counties on the map to view its corresponding detailed FAP or NHS. If the route is outlined in GREEN, it is an FAP road. If it is outlined in RED, it is an NHS road. In either case, a local ordinance is required from each municipality along the corridor. The ordinance must specify how the placement of new signs, displays, or devices will be prohibited on the byway in conformance with 23 U.S.C. §131. If using an existing ordinance, a resolution must be adopted reflecting consent to enforce the prohibition set forth for the byway and to not revise the ordinance without PennDOT's prior written approval. Failure to do so may result in revocation of the designation. Each PennDOT District has an Outdoor Advertising Coordinator on staff to provide technical assistance to byway sponsors.