Covenant of the state.

The state pledges to, and agrees, with any person, firm or corporation, or federal or state agency subscribing to, or acquiring the bonds to be issued by the authority for the purposes of this part that the state will not limit or alter the rights that are vested in the authority and the department until all issued bonds and interest are fully paid and discharged insofar as the pledge affects the rights of the holders of bonds issued pursuant to this part. The state does further pledge to, and agree, with the United States that in the event any federal agency constructs or contributes any funds for the completion, extension, or improvement of the Central Florida Expressway System, or any part or portion of the system, 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 Central Florida Expressway System or the completion, extension, or improvement of the system, 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 granted in this part, so long as the powers are necessary or desirable for the carrying out of the purposes of this part and the purposes of the United States in the completion, extension, or improvement of the Central Florida Expressway System, or any part of the system.