(a) As the chief executive officer of the department, the commissioner shall have direct and full control of the department. He or she shall possess, exercise, and perform all the duties, powers, and authority which may be vested in the department by law, except those duties, powers, and authority which are expressly reserved by law to the board or the director of planning. The commissioner's principal responsibility shall be the faithful implementation of transportation plans produced by the director of planning and approved by the Governor and the State Transportation Board, subject to the terms of such appropriations Acts as may be adopted from time to time. The commissioner shall also be responsible for the duties and activities assigned to the commissioner in Article 5 of Chapter 8 of Title 48. When the board is not in regular or called session, the commissioner shall perform, exercise, and possess all duties, powers, and authority of the board except:

(1) Approval of the advertising of nonnegotiated construction contracts; and

(2) Approval of authority lease agreements.

The commissioner shall also have the authority to exercise the power of eminent domain and to execute all contracts, authority lease agreements, and all other functions except those that cannot legally be delegated to him or her by the board.

(b)

(1) The commissioner shall have the authority to employ, discharge, promote, supervise, and determine the compensation of such personnel as he or she may deem necessary or useful to the effective operation and administration of the department except that the commissioner shall not employ a person who is related within the second degree of consanguinity to the commissioner or any member of the board, provided that such prohibition shall not be applied so as to terminate the employment of persons employed before said prohibited relationship was created by the subsequent election of a board member or appointment of a commissioner.

(2) Notwithstanding the provisions of subsection (b) of Code Section 32-6-29, the commissioner shall have the authority to appoint and employ five nonuniformed investigators who shall be certified peace officers pursuant to the provisions of Chapter 8 of Title 35, the "Georgia Peace Officer Standards and Training Act." The investigators shall have full arrest powers in cases involving internal affairs of the department and in cases involving obstruction of, encroaching on, or injury to public roads or rights of way. In such cases, the investigators shall be authorized:

(A) To investigate Department of Transportation related crimes committed anywhere in the state;

(B) To arrest any person violating the criminal laws of this state;

(C) To serve and execute warrants after notifying the law enforcement agency of the local jurisdiction of the intent to serve such warrant or warrants;

(D) To enforce in general the criminal laws of this state;

(E) To issue citations for civil damage to any person found to be violating the laws, rules, and regulations pertaining to vegetation management; and

(F) To carry firearms while performing their duties but only if such investigators have been certified by the Georgia Peace Officer Standards and Training Council as having successfully completed the course of training required by Chapter 8 of Title 35, the "Georgia Peace Officer Standards and Training Act."

(3) The power granted to the commissioner in paragraph (1) of this subsection shall be subject to and limited by Article 1 of Chapter 20 of Title 45 establishing a merit system for department employees, to the extent that the same or any amendments thereto are now or may be hereafter applicable to department personnel.

(4) There shall be a Planning Division of the department, directed and staffed by the director of planning, which shall be the department's principal unit for developing the state transportation improvement program and the state-wide strategic transportation plan and coordinating transportation policies, planning, and programs related to design, construction, maintenance, operations, and financing of transportation, under the supervision of the director. The division and the director shall not have jurisdiction over the funds allocated for the local maintenance and improvement grant program pursuant to subsection (d) of Code Section 32-5-27 except as expressly provided by said subsection.

(5) There shall be an Engineering Division of the department to be supervised by the chief engineer, a Finance Division of the department to be supervised by the treasurer, an Administration Division of the department to be supervised by the deputy commissioner, an Intermodal Division to be supervised by an appointee serving at the pleasure of the commissioner, and a Local Grants Division to be supervised by an appointee serving at the pleasure of the commissioner. The duties, responsibilities, and personnel of each such division shall be as established by the commissioner.

(6) The commissioner may establish a Construction Division, an Operations and Maintenance Division, a Permitting Division, and a Public-Private Initiatives Division of the department. The commissioner shall assign to such divisions, except as otherwise provided by law, such personnel and such duties and responsibilities as may be necessary and appropriate for the proper functioning of the department.