53 Pa. Stat. § 13812
In all cases wherein the proper authorities of any city of the first class in this commonwealth shall have directed or may hereafter direct in the manner provided for by law, that any of the streets upon the public plans of such city shall be opened or widened according to such plan thereof, or that the chief commissioner of highways of such city should or shall give notice of such opening or widening to the owners of ground to be taken thereby, it shall be lawful for such city by the mayor or any other officer thereof to present a petition to the court of quarter sessions of the peace of the proper county asking the appointment of a jury or viewers to assess the damages which such owners may sustain by the opening or widening of such streets.
53 P.S. § 13812