Did the Police Have Probable Cause to Arrest Me for DUI?

 Posted on June 25, 2026 in DUI

If the police did not have probable cause to arrest you for driving under the influence, your attorney may be able to ask the court to suppress evidence gathered after the arrest, including chemical test results and other evidence obtained as a result of the unlawful arrest. Without that evidence, the state's case against you can fall apart entirely. If you are facing a DUI charge in 2026 and questioning whether the arrest was legal, the Naperville, IL DUI defense lawyers at Appelman Law LLC can review exactly what happened and fight to protect your rights.

What Is Probable Cause and Why Does It Matter?

Probable cause is the legal standard police must meet before they can arrest someone. It means that based on the facts and circumstances the officer observed, a reasonable person would believe that a crime had been committed. It is a higher bar than just a hunch or a suspicion. But it does not require proof beyond a reasonable doubt.

Under 725 ILCS 5/107-2, they do not need a warrant if they have probable cause to believe that a person is committing or has committed a criminal offense. In a DUI stop, that means the officer has to be able to point to specific facts, not just a general sense that something seemed off, to justify taking you into custody.

In a DUI case, probable cause to arrest is separate from the reason the officer pulled you over in the first place. The initial traffic stop requires only reasonable suspicion, a lower standard. But once you are stopped, the officer needs to develop probable cause before they can place you under arrest.

If the officer did not have enough to justify the arrest, the arrest itself was unlawful. And when an arrest is unlawful, everything that follows it can be challenged.

What Can an Officer Use to Establish Probable Cause for a DUI Arrest?

Officers look for specific signs of impairment during a traffic stop. They document everything they see, smell, and hear from the moment they approach your vehicle. Common things officers use to build probable cause include:

• The smell of alcohol coming from the vehicle or your breath

• Bloodshot or watery eyes

• Slurred speech

• Difficulty finding your license, registration, or insurance

• Open containers of alcohol in the vehicle

• Admission that you had been drinking

• Poor performance on field sobriety tests

• Results from a portable breath test, where applicable

Officers typically rely on a combination of observations. The more signs an officer documents, the stronger their argument that probable cause existed.

Can Field Sobriety Test Results Be Challenged?

Field sobriety tests are not always reliable indicators of impairment. Things that can affect field sobriety test performance have nothing to do with alcohol. Medical conditions, injuries, nervousness, uneven pavement, poor lighting, and even the type of shoes you wear can all affect how you perform. If any of these factors were present, your attorney can use them to challenge whether the test results actually supported probable cause.

What if the DUI Traffic Stop Itself Was Not Legal?

Before officers can even begin building probable cause for a DUI arrest, they need a valid reason to pull you over in the first place. That is called reasonable suspicion. Officers need to be able to point to specific, observable facts that suggest a traffic violation or criminal activity was occurring.

If the stop was not legally justified, much of the evidence obtained afterward may be subject to suppression. That includes the officer's observations, the field sobriety test results, and any chemical test results. A motion to suppress evidence based on an unlawful stop is one of the most powerful tools a DUI defense attorney has.

What Happens if Probable Cause Did Not Exist in Your DUI Case?

If your attorney can show that the officer lacked probable cause to arrest you, they can file a motion to suppress the evidence obtained as a result of that unlawful arrest. This is a formal legal request asking the court to exclude evidence that was gathered in violation of your Fourth Amendment rights. If the motion to suppress is granted, the state loses the ability to use that evidence against you, which often means the case cannot go forward at all.

Schedule a Free Consultation With Our DuPage County DUI Defense Attorneys

A DUI charge does not have to become a DUI conviction, and the first place to look for a strong defense is the arrest itself. Attorney Appelman holds a Master's Degree in Forensic Psychology, which gives him a deeper understanding of how field sobriety tests work, why they fail, and how to challenge them effectively in court. That background, combined with years of DUI defense experience, means he looks at these cases differently than most attorneys do. When you need answers, someone is always available to take your call.

Contact our Naperville, IL DUI defense lawyers at Appelman Law LLC by calling 630-717-7801 today. Our attorneys are available by phone 24 hours a day, seven days a week.