23 CFR § 630.705 - Procedures.
(a) An advance construction project shall meet the same requirements and be processed in the same manner as a regular Federal-aid project, except,
(1) The FHWA authorization does not constitute any commitment of Federal funds on the project, and
(2) The FHWA shall not reimburse the State until the project is converted under § 630.709.
(b) Project numbers shall be identified by the letters “AC” preceding the regular project number prefix.