36 Pa. Stat. § 659.3
The commission is hereby authorized to borrow money from time to time, to provide for preliminary or interim financing but not exceeding the estimated total cost of any project, and to evidence such borrowing by the issuance of notes or other obligations of the Commonwealth, payable solely from revenues of the commission, including tolls, or from such funds as may be available to the commission for such purpose and, in its discretion, to pledge revenue bonds as collateral for such notes or other obligations, and to renew any such notes or other obligations from time to time; and the payment or retirement of such notes or other obligations shall be considered to be payment of the cost of such project.
All State and municipal officers and administrative departments, boards and commissions of the Commonwealth, all banks, bankers, savings banks, trust companies, saving and loan associations, investment companies, and other persons carrying on a banking business, all insurance companies, insurance associations, and other persons carrying on an insurance business, may properly and legally invest any funds, including capital belonging to them or within their control, in such notes or other obligations, or loan any such funds and accept as evidence of the same such notes or other obligations.
All such notes or other obligations, their transfer, and the income therefrom including any profits made on the sale thereof, shall at all times be free from taxation within the Commonwealth.
All such notes or other obligations shall have and are hereby declared to have all the qualities and incidents of negotiable instruments under the Negotiable Instruments Law of the Commonwealth.
36 P.S. § 659.3