In Illinois, you can be charged with DUI if you drive a vehicle, or are simply in “actual physical control” of one, with a blood alcohol concentration (BAC) of 0.08 or more. You can also be charged if you’re impaired by alcohol, cannabis, or drugs to the point you can’t drive safely (625 ILCS 5/11-501). A single DUI arrest sets off two completely separate cases at the same time. One is a criminal case that can put a conviction on your record. The other is an administrative case that goes after your driver’s license automatically, on its own deadline.
This article walks through both. It covers what the state actually has to prove, the license suspension that starts running the moment you’re arrested, whether you’ll go to jail and what a first offense costs, the difference between court supervision and a conviction, and when a DUI becomes a felony.
What counts as a DUI in Illinois?
A DUI in Illinois isn’t just “driving drunk.” Under 625 ILCS 5/11-501(a), the state can charge you six different ways, and it only needs to prove one of them.
The two most common are the “per se” charge and the “impairment” charge. Per se (Latin for “by itself”) means your BAC was 0.08 or higher. That number alone is the crime, and the prosecutor doesn’t have to prove you were actually a bad driver. The Illinois Supreme Court confirmed this in People v. Martin, 2011 IL 109102. A per se DUI is a strict-liability offense, meaning proof of the number is proof of the crime. The impairment charge under 11-501(a)(2) is different. Here the state argues you were “under the influence” and less able to drive safely. It proves that through the officer’s observations, your driving, and field sobriety tests rather than the number alone.
The statute also reaches beyond alcohol. You can be charged for driving with 5 nanograms or more of THC (the active compound in cannabis) in your blood, for any amount of an illegal controlled substance in your system, or for impairment by any drug. Having a legal right to use a substance is generally not a defense to an impairment charge. Medical cannabis patients with a valid registry card are an exception on the per se THC charge. They’re exempt from the 5-nanogram limit unless they were actually impaired.
One point that surprises people: you don’t have to be moving, or even have the engine on. Illinois can charge you for being in “actual physical control” of the vehicle. Courts decide this case by case, weighing where you were sitting, whether the keys were in reach, and whether you could have driven off (People v. Slinkard, 362 Ill. App. 3d 855). Sleeping it off in a parked car with the keys in your pocket can still be a DUI.
None of this means an accusation is a conviction. It means you need to understand exactly which version of the charge you’re facing. That determines what the state has to prove, and where it can fail.
Why am I facing two separate cases from one arrest?
Because Illinois treats your license and your criminal record as two different problems, handled by two different authorities on two different clocks. This is the single most important thing to understand. It’s the reason you may have walked away from your arrest holding paperwork with dates that don’t match.
The criminal case runs through the county court. That’s where jail, fines, probation, court supervision, and a permanent conviction are decided, under 625 ILCS 5/11-501.
The license case, called a statutory summary suspension, runs through the Illinois Secretary of State, automatically, under 625 ILCS 5/11-501.1. No judge orders it. It happens on its own, simply because you either failed a chemical test or refused one. It moves faster than your criminal case, it has an earlier deadline, and it will suspend your license even if you’re never convicted of anything.
Fighting one does nothing for the other. You can beat the suspension and still face the criminal charge, or resolve the criminal case and still lose your license. Everything below is organized around this split, and the license side comes first, because its clock is already running.
What happens to my license, and what is the 46-day deadline?
Your license is scheduled to be suspended on the 46th day after your arrest, automatically, unless you formally challenge it first. This administrative suspension is the fastest-moving consequence of a DUI. It catches people off guard because it happens whether or not you’ve been to court and whether or not you’re ultimately convicted.
The reason it’s nearly automatic is built into the numbers. In 2024, 90% of eligible DUI arrestees lost their driving privileges through statutory summary suspension. How long you lose them depends on what happened at the station:
- Failed the test (BAC 0.08+) as a first offender: 6-month suspension.
- Refused the test as a first offender: 12-month suspension, and refusal blocks you from the permit that would otherwise let you keep driving.
- Not a first offender (a DUI or suspension in the past 5 years): 12 months for a failure, 36 months for a refusal.
You are not stuck accepting it. You have the right to file a petition to rescind, a written request asking a judge to cancel the suspension, under 625 ILCS 5/2-118.1. The statute gives you 90 days to file, but the deadline that actually matters is the 46th day, when the suspension takes effect. File early enough and you can force a hearing before your license goes down. This is your challenge to bring, and it puts four things squarely in issue: whether you were properly arrested, whether there were real grounds to believe you were driving under the influence, whether you were properly warned, and whether the test actually complied with the rules. You carry the initial burden to show something was wrong, but once you make that showing, the burden shifts to the State to defend the suspension (People v. Orth, 124 Ill. 2d 326). A first offender who failed the test may also qualify for a Monitoring Device Driving Permit (MDDP), which lets you keep driving with a breath-interlock device installed in your car.
The practical takeaway: the window to protect your license is measured in weeks, not months, and it opens the day you’re arrested. Waiting until your first court date can be too late.
Will I go to jail, and what will a first DUI cost me?
For a first DUI, jail is possible but far from the most likely outcome, and a conviction itself is not the most common result. Most first-time DUI arrests in Illinois do not end in a DUI conviction.
Here’s the reassuring part, backed by the state’s own data. 87% of everyone arrested for DUI in Illinois is a first-time offender. And among first-time offenders, only 22% are actually convicted of DUI, compared to 52% of repeat offenders. Across all DUI cases with a court outcome, 61% received court supervision and only 35% resulted in a conviction. Supervision is a non-conviction outcome, explained in the next section.
Now the ceiling. A first DUI is a Class A misdemeanor under 625 ILCS 5/11-501(c), the most serious class of misdemeanor. It carries up to 364 days in jail and a fine of up to $2,500. That’s the maximum the law allows, not the norm for a first offense. Certain facts trigger mandatory add-ons. A BAC of 0.16 or higher adds a mandatory $500 fine and 100 hours of community service. Driving with a passenger under 16 brings its own mandatory jail or community service and a $1,000 fine.
As for being held in jail before your case is resolved, that’s now rare. Since Illinois eliminated cash bail under the Pretrial Fairness Act in September 2023, the overall pretrial detention rate dropped from 33% to 9%. Standard first-offense DUIs are generally not eligible for pretrial detention at all, so most people are released with conditions rather than held.
The honest summary: the worst case has a defined ceiling, jail before trial is unlikely, and the most common outcome for a first offense keeps a conviction off your record entirely.
What is court supervision, and how is it different from a conviction?
Court supervision is an outcome that lets you resolve your DUI without a conviction going on your record. For a first offense, it’s usually the goal. Instead of convicting you, the judge holds the case open while you complete conditions like a DUI evaluation, treatment, and a period of good behavior. Finish them, and the case ends without a DUI conviction under 730 ILCS 5/5-6-1.
The difference between supervision and a conviction is enormous. A DUI conviction triggers a mandatory license revocation and stays on your record permanently. Illinois does not allow DUI convictions to be expunged or sealed. Successfully completed supervision avoids that revocation.
There is one catch you cannot afford to get wrong: DUI supervision is available only once in your lifetime. Use it on this case, and it’s gone for any future one. And courts count prior supervision against you. The Illinois Supreme Court held in People v. Sheehan, 168 Ill. 2d 298, that a completed supervision still counts as a prior DUI that can push a later offense up to a felony. That’s exactly why the first DUI matters so much: how it’s resolved shapes every consequence that could follow.
When does a DUI become a felony in Illinois?
A DUI becomes a felony, called aggravated DUI under 625 ILCS 5/11-501(d), when certain facts are present, either because of your record or because of what happened. A basic first or second DUI is a misdemeanor. Specific aggravating factors are what cross the line into felony territory.
Your record is one path up the ladder:
- Second DUI: still a Class A misdemeanor, but now with a mandatory minimum of 5 days in jail or 240 hours of community service, no court supervision available, and a 5-year license revocation.
- Third DUI: a Class 2 felony, punishable by 3 to 7 years in prison, with a 10-year revocation.
- Fourth or more: felony with no probation available on a fourth, escalating to Class 1 and Class X felonies, up to 6 to 30 years, for fifth and subsequent offenses.
Two things make this harsher than people expect. Illinois has no lookback period: there’s no window after which an old DUI stops counting. Every prior DUI counts, no matter how long ago. And prior supervision counts as a prior offense for this purpose, per Sheehan.
The facts of a single arrest can also jump even a first-timer straight to a felony. Aggravated DUI under 11-501(d) includes causing great bodily harm or death, driving on a license already suspended or revoked for DUI, driving without a valid license or without insurance, driving a school bus with passengers, or causing bodily harm to a child under 16. A DUI that causes a death is a Class 2 felony carrying 3 to 14 years for a single death, and more for multiple.
Where your situation sits on this ladder determines nearly everything about your risk. That’s why the specific charge and your exact record matter more than the general label “DUI.”
What should I do right now?
Three steps, in order:
- Protect your license immediately. The suspension is scheduled for the 46th day after arrest. A petition to rescind has to be filed and heard before then to keep your license, so this is the first clock to beat.
- Don’t resolve the criminal case on your own. Don’t plead before you understand what’s at stake: your one-time court supervision and a permanent conviction are both on the line.
- Talk to a DUI attorney now, while the license deadline and the criminal case are still open.
This is the work DRD Law, LLC does. Based in Chicago at 332 S. Michigan Avenue, the firm is led by David R. Drwencke, a criminal defense attorney with an evidence-based defense philosophy. Before founding DRD Law, David spent nearly seven years as a judicial law clerk in circuit court, where he observed hundreds of trials and gained insight into how judges think and rule. He has been named an Illinois Super Lawyers Rising Star every year from 2019 through 2026, holds Martindale-Hubbell’s AV Preeminent rating, and has handled 565+ criminal defense cases. Because both your license case and your criminal case are already on the clock, with your one-time court supervision and your record on the line, the firm offers 24/7 attorney communication and real-time case tracking through its client app, so that in a DUI, when the first days matter most, you’re not waiting to reach your lawyer.
If you’re facing a DUI in Chicago or the surrounding counties, contact DRD Law, LLC before your deadlines pass.
This article is general legal information about Illinois DUI law, not legal advice. Every case turns on its own facts, and the law changes. Reading it does not create an attorney-client relationship with DRD Law, LLC. For advice about your specific situation, speak with a licensed Illinois attorney.
