605 ILCS 5/4-102

The Department may prepare, in accordance with the regulations of the designated authority of the United States Government, the project statements, sketch maps, surveys, plans, specifications, estimates, bid forms, contracts and bonds to be used in connection with the construction of any of the federal aid highways in this State. The Department may construct any federal aid work provided for in Article 3 and purchase and supply any labor, tools, machinery, supplies and materials needed for any such work. Such construction work and labor shall be performed in accordance with the general laws of this State, and under the direct supervision of the Department, subject to the inspection and approval of the designated authority of the United States Government, and in accordance with its rules and regulations.