30 ILCS 540/3-6

If an agency incurs an interest liability under this Act that cannot be charged to the same expenditure authority account to which the related goods or services were charged due to federal prohibitions, the agency is authorized to pay the interest from its available appropriations from the General Revenue Fund, except that the Department of Transportation is authorized to pay the interest from its available appropriations from the Road Fund, as long as the original goods or services were for purposes consistent with Section 11 of Article IX of the Illinois Constitution.