How Do I Challenge a DUI Charge in Illinois?

 Posted on June 23, 2026 in DUI

There are many ways to challenge a DUI charge in Illinois. The state has to prove every element of the offense beyond a reasonable doubt. Your attorney can help you push back against their claims. If you are facing a DUI charge in 2026, our Naperville, IL DUI defense lawyer will review every detail of your case and identify the strongest arguments available to you.

Questions To Ask When Building a DUI Defense Strategy

Consider some things your attorney will ask about your case while building your defense strategy.

Was the Traffic Stop Legal?

Before an officer can pull you over, they need what is called reasonable suspicion that a traffic violation or criminal activity is occurring. That means they need specific, observable facts, not just a feeling or a hunch.

If the stop was not legally justified, any evidence they collected may be thrown out. That includes field sobriety test results, breathalyzer readings, and anything you said to the officer. Without that evidence, the prosecution's case can fall apart entirely.

Common reasons stops are challenged include vague claims of weaving within a lane that did not actually violate the law, stops based on tips that were not sufficiently verified, and stops for minor equipment issues that did not constitute a legal violation. Your attorney will review the police report carefully and look for any weaknesses in the reason the officer gave for pulling you over.

How Did the Officer Administer the Field Sobriety Tests Properly?

Field sobriety tests are not as reliable as many people think. The National Highway Traffic Safety Administration regulates how they are given. If an officer did not follow those standards, the results may not be valid. That means the results can be challenged in court.

Even when tests are administered correctly, outside factors can affect how a person performs. Uneven or sloped pavement, poor lighting, wind or rain, nervousness, certain medical conditions, and even the type of shoes you were wearing can all affect the results. None of these things has anything to do with alcohol or impairment. However, they can make someone look impaired on a test.

Can You Question the Breathalyzer Results?

Breathalyzer results are not automatically accurate. The device used to test your breath requires maintenance on a regular schedule. The officer administering the test also has to be properly trained and certified to use it. Failure to uphold these standards means that the results may not be reliable. Your attorney can request maintenance and calibration records as part of the investigation into your case.

Some people get high breathalyzer readings that have nothing to do with how much they drank. Medical conditions like acid reflux and diabetes can interfere with how the device reads your breath. Following a low-carbohydrate diet can do the same thing. The device picks up compounds produced by your body and mistakes them for alcohol. If you have any of these conditions, your attorney will look closely at whether they could explain your result.

Under 625 ILCS 5/11-501.2, Illinois law governs how chemical tests must be conducted in DUI cases. Any deviation from the required procedures is worth examining closely.

What Is a Motion to Suppress and How Can It Help?

A motion to suppress is a legal request asking the court to exclude evidence that was obtained in a way that violated your constitutional rights. It is one of the most powerful tools available in a DUI defense case.

If your attorney can show that the traffic stop was not legally justified, that a search of your vehicle was conducted without proper authority, or that your rights were violated during the investigation, the court may agree to keep that evidence out of your case.

Schedule a Free Consultation With Our Naperville DUI Defense Attorney

A DUI charge is not something you have to accept without a fight. Attorney Phil Nathe is a former Assistant State's Attorney in DuPage County, which means he has seen these cases from both sides. He knows how prosecutors build DUI cases and exactly where the weaknesses are. With over 25 years of legal experience, he brings the kind of knowledge and courtroom presence that makes a real difference in how a case turns out.

Contact a Naperville, IL DUI defense lawyer at the Law Office of Philip R. Nathe by calling 630-416-7600 to schedule your free consultation and talk about building your defense today.