16 Pa. Stat. § 2721
Whenever such system of main thoroughfares had been adopted or when the adoption thereof is contemplated within two years after the commencement of such improvement, the commissioners may take exclusive control of and improve any road or section thereof located either wholly or in part in any municipal corporation, whether existing by their authority or laid out in whole or in part by virtue of this act or otherwise. For that purpose, they may originally locate, lay out, establish in whole or in part relocate, straighten, widen, extend, alter and open roads, and construct and improve the same, and vacate so much of any roads as may be thereby rendered unnecessary and useless. Any road as established or altered, constructed and improved, under the provisions of this section, shall, by ordinance enacted by each municipal corporation through which such road shall pass, become municipal roads, and the duty of maintaining and keeping the same in repair shall devolve upon each respective municipal corporation through or into which the same extends.
16 P.S. § 2721