75 Pa.C.S. § 6121: Uniform system of traffic-control devices.

The department shall publish a manual for a uniform system of traffic-control devices consistent with the provisions of this title for use upon highways within this Commonwealth. The uniform system shall correlate with and so far as possible conform to the system set forth in the most recent edition of the Manual on Uniform Traffic-Control Devices for Streets and Highways and other standards issued or endorsed by the Federal Highway Administrator, United States Department of Transportation.