605 ILCS 5/10-310
The county board of each such county shall establish by ordinance the beginning and ending of a fiscal year for the operation of each such bridge, which period shall constitute the budget year for the maintenance and operation of each such bridge, and at least 30 days prior to the beginning of the first full fiscal year after the completion of each such bridge, the county board shall prepare a tentative budget which shall include all proposed operation and maintenance expenses for the ensuing fiscal year. Such budget shall be considered by the county board and after consideration and any revision as may be determined by such county board, it shall be adopted within 30 days after the beginning of each fiscal year by such county board as the budget for the ensuing year and no expenditures in excess of the budget shall be made during such fiscal year unless authorized and directed by a four-fifths vote of the county board of each such county. It shall not be necessary to include in such budget any statement of necessary expenditures for debt service or capital outlay incurred in any preceding year, but the county board shall make provision for such payments as they become due. Upon the adoption of such budget a copy thereof shall be filed in the office of the county clerk and shall be open for inspection by the public. The funds of the county derived from the operation of any such bridge shall not be subject to the provisions of "An Act in relation to the budgets of counties not required by law to pass an annual appropriation bill," approved July 10, 1933, as amended.
605 ILCS 5/10-310