Covenant of the state.

The state does hereby pledge to and agree with any person, firm, corporation, or federal or state agency subscribing to or acquiring the bonds to be issued by the authority for the purposes of this chapter that the state will not limit or alter the rights hereby vested in the authority and the department until all bonds at any time issued, together with the interest thereon, are fully paid and discharged insofar as the same affects the rights of the holders of bonds issued hereunder. The state does further pledge to and agree with the United States and any federal agency that, in the event that any federal agency shall construct or contribute any funds for the completion, extension, or improvement of the Jacksonville Expressway System or other transportation facilities of the authority, or any part or portion thereof, the state will not alter or limit the rights and powers of the authority and the department in any manner that would be inconsistent with the continued maintenance and operation of the Jacksonville Expressway System or other transportation facilities of the authority or the completion, extension, or improvement thereof, or that would be inconsistent with the due performance of any agreements between the authority and any such federal agency, and the authority and the department shall continue to have and may exercise all powers herein granted, so long as the same shall be necessary or desirable for the carrying out of the purposes of this chapter and the purposes of the United States in the completion, extension, or improvement of the Jacksonville Expressway System or other transportation facilities of the authority, or any part or portion thereof.