Upon the completion of any bridge or bridges authorized under the provisions of this act, the Department of Highways shall collect tolls from the users of such bridge, in such amount and upon such terms and conditions as may be approved by the Public Service Commission. When sufficient tolls have been collected to cover maintenance charges, and to repay any balance due the Reconstruction Finance Corporation or such other agency of the Federal Government for advancements made as herein provided, said bridge or bridges shall become free, and the collection of tolls shall thereupon cease. Thereafter said bridge or bridges shall be maintained by the Department of Highways out of the Motor License Fund.
36 P.S. § 3160a