36 Pa. Stat. § 668.2
In order to facilitate vehicular traffic in the western and northwestern sections of the Commonwealth, the Pennsylvania Turnpike Commission heretofore created by virtue of the provisions of the act, approved the twenty-first day of May, one thousand nine hundred thirty-seven (Pamphlet Laws 774), and the supplements and amendments thereto, is hereby authorized and empowered to construct, operate and maintain a turnpike, at such location as shall be approved by the Governor and the Department of Highways, from a point at or near the City of Erie in Erie County, thence in a general southerly direction to connect with the Pennsylvania Turnpike System at such point as the Pennsylvania Turnpike Commission may decide is most feasible and practicable, including a lateral extension eastward from such point as the Commission may decide is most feasible and practicable to the boundary line between the Commonwealth of Pennsylvania and the State of New York, and a lateral extension westward from such point as the Commission may decide is most feasible and practicable to a point on the boundary line between the Commonwealth of Pennsylvania and the State of Ohio, together with connecting roads, tunnels and bridges; and further, to issue turnpike revenue bonds of the Commonwealth, notes or other obligations, payable solely from revenues of the Commission, including tolls, or from such funds as may be available to the Commission for that purpose, to pay the cost of any and all construction.
36 P.S. § 668.2