Upon payment in full of all bonds and the interest thereon and obligations of every nature whatsoever for the payment of which the revenues of any given project or projects have been pledged, in whole or in part, either originally or subsequently, either primarily or secondarily, directly or indirectly or otherwise, or upon the setting aside in trust, for the benefit of bondholders or other obligees, of a sufficient amount for the payment of all such bonds and other obligations and the interest thereon to the maturity thereof, such project or projects, if deemed by the department to be in a safe and satisfactory condition of repair and traffic capacity, may become part of the state highway system and thereafter shall be maintained by the department free of tolls. In the event such project or projects to be transferred are not in good condition, in the judgment of the department, the department shall be charged with the duty of immediately advising the authority in writing what will be necessary to accomplish such safe and satisfactory condition of repair and traffic capacity; and the authority thereafter shall apply sufficient revenue from such project or projects to the accomplishment of such safe condition of repair and traffic capacity; and, upon its accomplishment, such project or projects shall become toll free as provided in this Code section. Upon the fulfillment of all conditions necessary to the cessation of tolls upon any such project, the authority shall convey by deed all right, title, and interest in and to such project to the department for and in consideration of $1.00, which the treasurer of the department is authorized to pay from any department funds available to him for any department expenditure.