36 Pa. Stat. § 670-416
Whenever it shall appear that any part or portion of a State highway in any township is dangerous to the traveling public, and such danger could be materially reduced or lessened by the construction of a sidewalk, the department may aid the local authorities to lay out and construct a sidewalk along such dangerous portion of State highway. Such sidewalks shall be constructed in such manner, and of such materials as deemed advisable by the department, but shall be raised at least five inches above the surface of the highway. All sidewalks constructed under the provisions of this section shall be thereafter considered as a part of the State highway system, and shall be reconstructed, maintained and repaired, by the department, and the cost or proportion thereof agreed to be paid by the department shall be paid in the same manner as provided in this act in the case of State highways.
36 P.S. § 670-416