605 ILCS 5/4-103
Any contracts that may be entered into for the construction of highways shall be let after due public advertisement to the lowest responsible bidder, or bidders, upon terms and conditions to be fixed by the Department, and the Department shall also require the successful bidder, or bidders, to furnish good and sufficient bonds to insure proper and prompt completion of such work in accordance with the provisions of such contracts.
Partial payments may be made for the work as it progresses provided that the Department retains an amount as required by the Standard Specifications for Road and Bridge construction.
At the request of the contractor and with the approval of the Department the retainage of the contract may be deposited under a trust agreement with an Illinois financial institution, whose deposits are insured by an agency or instrumentality of the federal government, of the contractor's choice and subject to the approval of the Department.
The contractor shall receive any interest thereon.
Pursuant to application by the contractor, a trust agreement by the financial institution and the Department shall contain as a minimum, the following provisions:
The contractor shall be responsible for obtaining the written consent of the financial institution trustee, and any costs or service fees shall be borne by the contractor.
The trust agreement may, at the discretion of the Department and upon request of the contractor, become operative at the time of the first partial payment in accordance with existing statutes and Department procedures.
The provisions of this Section shall apply to all contracts in effect on and after the effective date of this amendatory Act of 1981.
605 ILCS 5/4-103