What Kind of Evidence Can Be Used Against You in a Chicago DUI Case?

Law Offices of David L. Freidberg, P.C.

If you’ve been pulled over and charged with DUI in Chicago, you’re likely wondering how the prosecution plans to prove their case. Illinois prosecutors don’t make arrests on a hunch — they build DUI cases using a wide range of evidence, each designed to meet the burden of proof beyond a reasonable doubt. From breath tests to body camera footage, everything the police collect may be used in court. The more you understand what evidence prosecutors rely on, the more you can see why having a seasoned Chicago DUI attorney makes a difference.

Driving under the influence (DUI) in Illinois is codified under 625 ILCS 5/11-501. A first offense is usually a Class A misdemeanor. But depending on aggravating factors, such as prior DUI convictions, having a child in the car, or causing injury, your charge can easily become a felony. And the higher the stakes, the more aggressive the prosecution’s tactics will be.

Police in Chicago and throughout Cook County begin gathering evidence from the moment they make the traffic stop. They observe your driving, how you respond to questions, and whether there are visible signs of impairment. Once you’re asked to step out of the vehicle, you may be asked to perform field sobriety tests. These roadside tests are standardized, but often misapplied or misunderstood — giving prosecutors fuel to argue impairment even when other evidence is thin.

One of the most powerful forms of evidence is the breathalyzer test at the station. If your blood alcohol concentration (BAC) is 0.08 or higher, it creates a presumption of impairment. That said, the machine must be properly calibrated, and the test administered by a certified officer. Any mistake here gives the defense a foothold.

Bodycam and dashcam footage are now routinely submitted as evidence in DUI trials. These recordings show how you spoke, moved, and behaved during the stop. While prosecutors present this as a visual confirmation of guilt, defense attorneys can often use the same footage to challenge the officer’s version of events or highlight procedural errors.

Prosecutors also rely on lab reports from blood or urine testing, particularly in drug DUI cases. However, proving that drugs impaired your ability to drive is far harder than proving the presence of alcohol — giving the defense room to introduce reasonable doubt.

The consequences of a DUI conviction in Illinois are harsh. Even for a first offense, you’re looking at possible jail time, steep fines, license suspension, mandatory alcohol classes, and a permanent mark on your criminal record. A third DUI becomes a Class 2 felony, with up to seven years in prison under Illinois law.

If you’re facing DUI charges in Chicago, you’re not alone. The Law Offices of David L. Freidberg has helped thousands of clients challenge DUI evidence and avoid life-changing penalties. Every case is different — and every case demands a legal strategy built on experience, scrutiny of the facts, and unshakable commitment.

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.

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