Belleville is the county seat of St. Clair County and the home of the 20th Judicial Circuit. DUI cases originating from Belleville Police, St. Clair County Sheriff's Office, or the Illinois State Police on the interstate segments all file in this circuit. Misdemeanor first offenses are handled at the Belleville Municipal Court level in some cases; aggravated DUIs and second-or-greater offenses go to the circuit.
Illinois DUI law differs from Missouri DWI in three structural ways that change the defense calculus. First, Illinois has a per-se DUI threshold for cannabis: 5 nanograms of delta-9 THC per milliliter of whole blood, or 10 ng/mL in another bodily substance (625 ILCS 5/11-501). Missouri has no such threshold. Second, the implied-consent consequences differ — Illinois's Statutory Summary Suspension is automatic on refusal (12 months first time, 3 years subsequent) and runs separately from the criminal case. Third, the 46-day Petition to Rescind window is your only opportunity to challenge the summary suspension administratively.
Defense angles in Illinois DUI cases focus on the same general areas as Missouri DWI: the constitutional basis for the stop, the procedural validity of the field sobriety tests, the calibration and administration of the breath or blood test, and the conditions surrounding any chemical refusal. But the specific statutory framework, jury instructions, and applicable case law are all Illinois-specific.
Court Supervision is the Illinois disposition most analogous to Missouri's SIS — a finding of guilt without entry of conviction, contingent on successful completion of probation. First-time DUI is supervision-eligible. Second-time DUI is not. Aggravated DUIs (involving death or great bodily harm, repeat offenses within specific windows, or driving while license suspended for prior DUI) are felonies and have their own framework.