Illinois Drivers Are Often Misled About What a Breath Test Result Actually Proves
It’s a moment that rattles thousands of Chicagoans every year—you’re pulled over on Lake Shore Drive or near I-290, and after a few words with the officer, you’re asked to blow into a handheld breathalyzer. The beep, the wait, and then the officer says, “You’re over the limit.”
But does that really mean you’re guilty?
Not necessarily.
In Illinois, breath test results are often treated like the final word, especially by those unfamiliar with how DUI law actually works. But the legal truth is far more complicated. You might have registered a 0.09 or higher, but that result is not infallible. And no matter how confident the police seem, the machine that delivered that number is only as good as the officers using it and the maintenance behind it.
The Illinois Vehicle Code under 625 ILCS 5/11-501 criminalizes driving with a BAC of .08 or higher. However, proving guilt requires more than just a number. The prosecution must establish that the breath test was conducted properly, that the machine was maintained and calibrated according to Illinois law, and that you weren’t subjected to illegal procedures.
More importantly, the Constitution protects you from unlawful searches and seizures—and that includes traffic stops and field sobriety tests that don’t meet the legal standard of probable cause.
In Chicago courtrooms, breath test results can be—and often are—challenged. So if you’re wondering whether you can beat a DUI in Illinois even after failing a breath test, the answer is yes. But it takes the right defense and the right attorney.
What Really Happens After a DUI Arrest in Illinois
If you’re arrested in Chicago or anywhere in Illinois for DUI, the process kicks off fast. First, you’ll be booked and processed, often at a local district station like the 1st District on South State Street or one of the suburban Cook County facilities. You’ll receive a Notice of Statutory Summary Suspension, informing you that your license will be suspended unless you contest it within 90 days.
This suspension is automatic—even before a court conviction—if you failed the breath test or refused it altogether.
Criminally, you’ll be charged with a Class A misdemeanor for a first DUI offense. Aggravated DUI, such as causing injury or having prior DUI convictions, can escalate the charge to a felony, even a Class 2 felony in severe cases.
The first formal hearing, the arraignment, takes place at a Cook County courthouse. Then your case moves into pretrial, where motions are filed, discovery is exchanged, and negotiations begin. If you don’t settle or plead, the case heads to trial.
Throughout all of this, the prosecutor’s case is only as strong as the evidence they’re allowed to present. That’s why your defense attorney will examine every detail—dash cam footage, arrest reports, breath machine logs, and body camera footage—to determine what evidence should be excluded.
In DUI law, what gets kept out of court can be just as important as what goes in.
Fictional Case Example: DUI Dismissed in Logan Square
A man was stopped in Logan Square just after midnight on a Thursday. Officers claimed he failed to signal and drifted in his lane. After a brief conversation, they said he smelled of alcohol and ordered him out of the car.
He complied with the field tests and eventually submitted to a breath test, which showed a BAC of 0.10. He was arrested and charged with misdemeanor DUI under 625 ILCS 5/11-501(a)(1).
But his attorney filed a motion to suppress based on unlawful stop. Dash cam footage showed he had in fact used his turn signal, and there was no visible weaving. Additionally, the machine used for the breath test had been calibrated 47 days late.
The judge ruled that both the stop and the breath test were invalid. The case was dismissed before it ever reached trial.
This is a reminder: police may act confident in their cause, but confidence is not the same as legal proof. And even failed breath tests can fall apart under legal scrutiny.
DUI Supervision and Probation Pitfalls: Missed Check-Ins and Other Traps
For many first-time offenders, Illinois offers court supervision instead of conviction. This can include alcohol treatment, DUI classes, community service, and probation-like conditions. But supervision is no free ride—it comes with serious responsibilities.
In Chicago, those on supervision or probation for DUI often face violations for missing check-ins, skipping drug testing appointments, arriving late to court-mandated classes, or failing to pay required fines.
These are technical violations, as opposed to substantive violations (like committing a new crime). Judges in Cook County and surrounding areas take a very different approach to each.
For a first-time missed curfew or late payment, courts may issue a warning or ask for an explanation. But repeated technical violations can result in your supervision being revoked. If that happens, you may end up convicted of the original DUI charge—and face jail time, a permanent criminal record, and a longer license suspension.
Defendants in DuPage County and Will County may find even stricter enforcement. That’s why having a lawyer by your side through not only the trial, but the entire supervision period, is vital.
Even if your original case seemed minor, failing to handle the post-conviction requirements properly can lead to life-altering consequences.
Why Police Evidence Isn’t Always Bulletproof
Police in Illinois rely on multiple types of evidence in DUI cases:
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Officer observations (slurred speech, bloodshot eyes)
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Field sobriety tests
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Dash and body cam footage
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Breath or blood test results
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Admissions made during arrest
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Witness testimony
But all of these have potential flaws.
Officers are trained to look for signs of impairment—but these signs can also be caused by fatigue, illness, allergies, or nervousness. Dash cam footage often contradicts what officers write in their reports. Machines used for breath testing are supposed to be maintained every 62 days and must have a current certification on file. If not, their results can be challenged.
Statements you made at the time of arrest may be tossed if your Miranda rights weren’t properly read or if you were coerced.
No case is perfect. And the more evidence the State tries to bring in, the more chances your defense lawyer has to find inconsistencies, constitutional violations, or technical errors.
DUI Defense in Chicago FAQs
Can I still fight a DUI in Illinois if I failed the breath test?
Yes. A failed breath test is not a guaranteed conviction. Breathalyzers must be properly calibrated and maintained, and the test must follow strict rules. If your attorney finds a problem with how the test was administered or how the stop occurred, the results could be thrown out.
How long will my license be suspended after a DUI arrest?
If you fail the breath test, your license will be suspended for 6 months. If you refuse, it can be 12 months. However, your attorney can file a petition to rescind the suspension. If successful, you may keep your license while your case is pending.
What’s the difference between a misdemeanor and felony DUI in Illinois?
Most first-time DUIs are misdemeanors. But DUI becomes a felony—known as Aggravated DUI—if there are prior convictions, you were driving with a revoked license, or someone was injured. Felony DUIs carry prison time and a permanent felony record.
What happens if I violate supervision or probation for DUI?
Violations like missing check-ins or failing to complete classes can result in your supervision being revoked. That means the original DUI charge could become a conviction, which leads to harsher penalties. Having a lawyer represent you at a violation hearing can help you avoid this outcome.
Is it better to take the breath test or refuse?
That depends. Refusing results in a longer license suspension, but also denies prosecutors key evidence. Taking the test may help you qualify for supervision. An attorney can advise you on what’s best based on your prior record and the circumstances.
Can a DUI conviction be expunged in Illinois?
No. DUI convictions are not eligible for expungement or sealing under Illinois law. However, if your case ends in supervision and you meet all conditions, you may avoid a permanent criminal record.
What happens at a DUI trial in Cook County?
The prosecutor will present their evidence, including test results and officer testimony. Your lawyer can cross-examine witnesses, present your own evidence, and file motions to suppress illegally obtained evidence. A judge or jury will then decide your guilt.
How long does a DUI case last in Illinois?
Most cases take several months. The pre-trial process involves motion hearings, license suspension hearings, discovery exchange, and negotiation. Trial may be set months out depending on court scheduling.
Do I really need a lawyer if I plan to plead guilty?
Yes. A lawyer can negotiate a better deal, protect your license, reduce fines, and possibly avoid a conviction through supervision. You may also qualify for alternative sentencing or have evidence suppressed that could change the outcome of your case.
How can The Law Offices of David L. Freidberg help?
Our team investigates every angle of your case—from illegal traffic stops to flawed testing procedures. We appear in courts throughout Cook, DuPage, Will, and Lake Counties and aggressively defend your freedom and driving privileges. We offer free consultations 24/7 at (312) 560-7100 or (800) 803-1442.
When You Need a Fighter, Call Us!
Whether you’re charged in downtown Chicago, Skokie, Maywood, Bridgeview, or Rolling Meadows, we’re ready. We appear regularly in courtrooms throughout Cook, DuPage, Will, and Lake Counties. And we don’t treat aggravated speeding as just another moving violation.
If you were arrested in Chicago, protect your future by contacting The Law Offices of David L. Freidberg. We have decades of experience handling DUI cases in Illinois. Our firm is available 24/7 to provide the legal defense you deserve.
Contact us today at (312) 560-7100 or toll-free at (800) 803-1442 for a free consultation. We’re available 24/7 to serve clients throughout Illinois, Cook County, DuPage County, Will County, and Lake County.