36 Pa. Stat. § 670-214
Where any section of a State highway route shall be, or has been relocated, the portion of the public road or highway, thus abandoned as a State highway route, shall be maintained by, and at the expense of, the township, borough, incorporated town or city wherein it is located, but the department shall in each case, before abandoning such portion of public road or highway, improve and repair the same so that it shall be in first class condition when it is taken over by the township, borough, incorporated town or city.
Where the width, lines or location of a State highway shall be or have been changed, altered or establish, according to law, in a manner which does not create an entirely new highway, the section or sections, or portions of the right of way of the highway, as previously established, which are not included within the changed, altered or established widths shall be considered vacated, if such portions or sections are not of the full width of the highway, as previously established.
36 P.S. § 670-214