74 Pa. C.S. § 8113
All money received from any bonds, notes or other obligations issued under this chapter shall be applied solely to the payment of the costs of the department, the costs of the turnpikes, the turnpike extensions and improvements and the toll road conversions, including the reconstruction of the converted roads as provided for in this chapter and the repayment to the Federal Treasury of any funds so required to be repaid pursuant to any special legislation passed by the Congress of the United States authorizing the conversion of toll-free roads to toll roads or to the appurtenant fund. There is created and granted a lien upon the money, until so applied, in favor of holders of the bonds, notes or other obligations or the trustee provided for in this chapter in respect of the bonds, notes or other obligations.
74 Pa.C.S. § 8113