605 ILCS 130/75
If the public private agreement provides for the construction of all or part of the Illiana Expressway project and the estimated construction costs under the agreement exceed $50,000,000, the Department must also require the contractor to finance an independent audit of any and all traffic and cost estimates associated with the agreement as well as a review of all public costs and potential liabilities to which taxpayers could be exposed (including improvements to other transportation facilities that may be needed as a result of the agreement, failure by the contractor to reimburse the Department for services provided, and potential risk and liability in the event of default on the agreement or default on other types of financing). The independent audit must be conducted by an independent consultant selected by the Department.
605 ILCS 130/75