The Director-State Engineer, for the Department of Transportation, shall:
(1) Have charge of the records of the department;
(2) Cause accurate and complete books of account to be kept;
(3) Supervise the signing of vouchers and orders for supplies, materials, and any other expenditures;
(4) Contract for consulting services;
(5) Employ all engineers, assistants, clerks, agents, and other employees required for the proper transaction of the business of the office or of the department and fix their titles, determine their duties and compensation, and discharge them in his or her discretion; and
(6) Sign and execute or supervise the signing and executing of all documents and papers, including contracts and agreements for highway construction and the purchase of machinery, materials, and supplies.