55 Pa. Stat. § 698.32
The effectuation of the authorized purposes of the commission created under this act shall and will be in all respects for the benefit of the people of this Commonwealth, for the increase of their commerce and prosperity and for the improvement of their health and living conditions; and since the commission will be performing essential government functions in effectuating such purposes, the commission shall not be required to pay any taxes or assessments upon any property acquired or used by it for such purposes or fees, bridge tolls or other charges imposed or authorized to be imposed by virtue of any law of this Commonwealth, except vehicle registration fees, liquid fuels taxes, fuel use taxes, gross receipts taxes imposed as an excise on the use of public highways and tolls imposed by the Pennsylvania Turnpike Commission. The commission shall have the power to make payments in lieu of taxes or special assessments. The bonds issued by the commission and their transfer and the income therefrom, including any profits made on the sale thereof, shall be free from State and local taxation within this Commonwealth, other than gift, estate, succession or inheritance taxes.
55 P.S. § 698.32