The foregoing limitation on the aggregate amount of indebtedness of the state shall not prevent:

(1) The issuance of obligations to refund or replace any such indebtedness existing at any time in an amount not exceeding 1.05 times the amount which, taking into account earnings from the investment of the proceeds of the issue, is required to pay the principal thereof, interest thereon, and any premium payable with respect thereto, and the costs incurred in accomplishing such refunding, as provided in chapter 39.53 RCW, as now or hereafter amended: PROVIDED, That any proceeds of the refunding, bonds in excess of those acquired to accomplish such refunding or any obligations acquired with such excess proceeds, shall be applied exclusively for the payment of principal, interest, or call premiums with respect to such refunding obligations;

(2) The issuance of obligations in anticipation of revenues to be received by the state during a period of twelve calendar months next following their issuance;

(3) The issuance of obligations payable solely from revenues of particular public improvements;

(4) A pledge of the full faith, credit, and taxing power of the state to guarantee the payment of any obligation payable from any of revenues received from any of the following sources:

(a) the fees collected by the state as license fees for motor vehicles;

(b) excise taxes collected by the state on the sale, distribution, or use of motor vehicle fuel; and

(c) interest on the permanent common school fund:

PROVIDED, That the legislature shall, at all times, provide sufficient revenues from such sources to pay the principal and interest due on all obligations for which said source of revenue is pledged.

Severability—1974 ex.s. c 111: "If any provision of this 1974 amendatory act, or its application to any person or circumstance is held invalid, the remainder of the act, or the application of the provision to other persons or circumstances is not affected." [ 1974 ex.s. c 111 s 6.]