36 Pa. Stat. § 670-761
The secretary may enter into agreement with cities of the first class, interstate joint commissions, persons, associations and corporations, public or private, for the sharing with the Commonwealth of the cost, exclusive of property damages, of widening such streets and relocating such highways as form part of the State highway system and constitute approaches to interstate bridges in cities of the first class. Cities of the first class and interstate joint commissions are hereby authorized and empowered to enter into agreements with the secretary and with persons, associations and corporations for the purposes of sharing the cost of widening said streets and relocating said highways, exclusive of property damages.
Cities of the first class and interstate joint commissions are further authorized and empowered to enter into agreements with each other and with persons, associations and corporations for the purpose of sharing the cost of property damage direct and not merely consequential thereto in connection with the widening of said streets and relocating of said highways.
36 P.S. § 670-761