36 Pa. Stat. § 3201
The Department of Highways is hereby authorized and directed to erect and construct a toll bridge over the Allegheny River from a convenient point in or near the Borough of Tarentum in Allegheny County, to a point on the opposite side of said river in the County of Westmoreland, to connect the State highways on both sides of said river and to acquire the necessary land for approaches thereto.
In the construction of said bridge and the approaches thereto and connections with existing State highways, the Department of Highways shall have, with the approval of the counties affected,--namely, Westmoreland and Allegheny, all of the powers and authority conferred, with respect to the relocation, widening or construction of State highways, including the exercise of the power of eminent domain. Any damages sustained by reason of taking property in the relocation, widening or construction of any such bridge, the approaches thereto and connections with State highways, shall be ascertained in accordance with laws applicable to the ascertainment of damages in relocating, widening or constructing State highways, and such damages, when ascertained, shall be paid by the Commonwealth or county or counties as may be agreed upon in accordance with the laws relating to State highways.
36 P.S. § 3201