36 Pa. Stat. § 670-502
After the highways on the rural State highway system shall have been taken over by the Commonwealth, they shall be built, rebuilt, constructed, reconstructed, repaired and maintained by the department, at the expense of the Commonwealth, but it shall, nevertheless, be lawful for the department to enter into agreements, in the discretion of the secretary, with counties or townships or with persons, associations of corporations for sharing with the Commonwealth the cost of construction, reconstruction and maintenance of such highways, or parts thereof. The construction or improvement of any such highways shall be of such width, type and location as may be determined by the secretary, with the approval of the Governor, and repairs and maintenance shall be of such type as shall be determined by the secretary.
The county commissioners of any county may, by resolution, and after approval of a grand jury of the county, take over, with the consent of the secretary, any State highway on the rural State highway system, or any section thereof, as a county road, to be maintained and improved in the manner provided by law for county roads. A description of any road or section so taken over, with the resolution of the county commissioners and the approval of the secretary, shall be filed on record in the office of the clerk of the courts of the proper county.
36 P.S. § 670-502