625 ILCS 5/18c-1503
It is the intent of the Legislature that the exercise of powers under Sections 18c-1501 and 18c-1502 of this Chapter shall not diminish revenues to the Commission, and that any surplus or deficit of revenues in the Transportation Regulatory Fund, together with any projected changes in the cost of administering and enforcing this Chapter, should be considered in establishing or adjusting fees and taxes in succeeding years. The Commission shall administer fees and taxes under this Chapter in such a manner as to insure that any surplus generated or accumulated in the Transportation Regulatory Fund does not exceed 50% of the previous fiscal year's appropriation and shall adjust the level of such fees and taxes to insure compliance with this provision.
625 ILCS 5/18c-1503