65 ILCS 5/1-2-1.2: Felony DUI prosecutions prohibited.

(a) A unit of local government, including a home rule unit, may not enforce any ordinance that prohibits driving under the influence of alcohol, other drug or drugs, intoxicating compound or compounds, or any combination thereof if, based on the alleged facts of the case or the defendant's driving history or record, the offense charged would constitute a felony under Section 11-501 of the Illinois Vehicle Code, unless the State's Attorney rejects or denies felony charges for the conduct that comprises the charge.

(b) A municipal attorney must (i) review the driving record of any defendant accused of violating any ordinance that prohibits driving under the influence of alcohol, other drug or drugs, intoxicating compound or compounds, or any combination thereof and (ii) if the offense charged would constitute a felony under Section 11-501 of the Illinois Vehicle Code, notify the State's Attorney of the county of the felony charges.

(c) This Section is a denial and limitation of home rule powers and functions under subsection (g) of Section 6 of Article VII of the Illinois Constitution.