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Defending Against Field Sobriety Test Results in a Chicago DUI Case
Field Sobriety Tests: What Chicago Drivers Need to Know
Chicago is a city with a constant police presence and strict DUI enforcement. The Chicago Police Department conducts thousands of DUI stops each year, particularly along major routes like Lake Shore Drive, the Kennedy Expressway, and neighborhood corridors through Wicker Park, Bronzeville, and Lincoln Park. In many of these cases, the officer’s primary evidence consists of what happened during a field sobriety test.
Under 625 ILCS 5/11-501, a person commits DUI when operating or being in physical control of a vehicle while impaired by alcohol, drugs, or intoxicating substances. The state classifies most first and second DUIs as Class A misdemeanors, but when aggravating factors such as injury, a suspended license, or prior offenses exist, prosecutors may charge the case as a Class 4 felony or higher. The stakes are serious—license loss, jail time, and a criminal record that can never be erased.
Most officers rely on the National Highway Traffic Safety Administration (NHTSA)’s standardized tests: the Walk-and-Turn, the One-Leg Stand, and the Horizontal Gaze Nystagmus. These tests were designed for controlled environments but are performed on Chicago streets at 2 a.m., often under poor lighting and stressful conditions. As an experienced Chicago DUI defense lawyer, I have seen hundreds of cases where clients were arrested based on flawed, incomplete, or improperly administered field tests. Understanding how to challenge this evidence is often the key to winning a DUI case in Cook County.
How a DUI Arrest and Investigation Unfolds in Illinois
Every DUI case begins with a traffic stop or a roadside investigation. Officers may pull a driver over for speeding, weaving, or a minor traffic infraction. Once they approach the vehicle, they observe behavior, smell, and speech to decide whether impairment may be involved. If they suspect alcohol or drug use, they request field sobriety testing.
Under Illinois law, these tests are not mandatory. You can legally refuse them, although most drivers don’t realize that in the heat of the moment. The officer will likely still arrest you, but refusal prevents the state from using unscientific results later. If you do perform the tests, every movement is recorded—either in a written report or on a body-worn camera.
The DUI arrest process follows strict procedure. After performing tests, if the officer believes there’s probable cause, you’ll be taken to a local station for chemical testing under 625 ILCS 5/11-501.1, the implied consent statute. Refusing chemical testing results in an automatic suspension, but even then, your attorney can contest the suspension through a Petition to Rescind Statutory Summary Suspension in the circuit court.
The investigative phase is where many cases can be attacked. Officers sometimes fail to record the full interaction, forget to mention preexisting injuries, or administer tests on uneven pavement. These mistakes become critical in suppressing evidence before trial.
Why Field Sobriety Tests Are Often Unreliable
Field sobriety tests were never designed for perfect accuracy. Even under ideal conditions, the NHTSA admits that the standardized tests correctly predict impairment roughly three-quarters of the time. That means one out of every four sober people could “fail.” In the real world, the numbers are far worse.
Environmental conditions play a major role in performance. Chicago weather is unpredictable, and the presence of snow, rain, or wind can affect balance. Streetlights or flashing squad car lights may disorient drivers, particularly during the Horizontal Gaze Nystagmus test. Medical conditions such as vertigo, anxiety, or neuropathy can mimic the signs of intoxication. Yet, many officers fail to ask about these factors.
Additionally, non-standardized tests—such as reciting the alphabet, touching your nose, or counting backwards—have no recognized scientific validity. Prosecutors frequently try to use them to bolster their case, but skilled defense attorneys can move to exclude them as irrelevant under Illinois Rule of Evidence 403 for being more prejudicial than probative.
When cross-examining an arresting officer, I often expose how their testimony contradicts their training or the official NHTSA manual. Small details—like whether the suspect’s heels were together, or whether the officer demonstrated the movement properly—can determine whether the test results hold any weight.
The Criminal Case Process in Illinois Courts
After arrest, the case is filed in Cook County Criminal Court or another county depending on jurisdiction. The next step is the initial appearance, where bond conditions are set. The defendant must appear at all future hearings or risk a bench warrant. During pretrial, your attorney requests discovery, which includes police reports, video footage, and any breath or blood results.
A skilled Chicago criminal defense attorney will then review the evidence to identify potential constitutional violations. If the stop lacked reasonable suspicion, if the detention exceeded legal limits, or if the officer administered tests without probable cause, your attorney can file motions to suppress under 725 ILCS 5/114-12. Winning such a motion often leads to dismissal or significant plea reductions.
If the case proceeds to trial, the prosecution bears the burden of proving guilt beyond a reasonable doubt. Because field sobriety tests are subjective, their weight before a jury depends on credibility. A good defense lawyer can show inconsistencies in how the officer applied their training, creating reasonable doubt.
A Realistic Chicago Case Example
One of my past cases involved a driver pulled over near Humboldt Park after allegedly running a stop sign. The officer claimed the driver’s eyes were glassy and speech was slurred. The driver, however, had a mild speech impediment and had worked a long shift before being stopped. During field testing, he struggled slightly on the Walk-and-Turn due to a knee injury from years earlier.
We obtained the body camera footage, which clearly showed uneven pavement and passing traffic interfering with the test. The officer also failed to ask about any physical impairments. We hired a medical expert to explain how knee instability would affect balance. The judge found the field sobriety tests unreliable and ruled that probable cause for arrest was lacking. The entire case was dismissed before trial.
This example highlights how critical it is to analyze video and physical evidence. Even when chemical testing exists, improper field testing can undermine the entire arrest.
Common Legal Defenses in Field Sobriety Test Cases
An experienced Chicago DUI lawyer can employ multiple strategies to challenge field sobriety test results:
- Invalid Administration: Proving that the officer deviated from NHTSA protocol.
- Medical or Physical Limitations: Using medical records to explain poor performance unrelated to intoxication.
- Environmental Conditions: Demonstrating poor lighting, weather, or traffic interference.
- Improper Training: Showing the officer lacked certification or had limited experience.
- Video Evidence Contradictions: Comparing officer testimony against dash or body cam footage.
These arguments often lead prosecutors to reduce or dismiss charges, particularly when chemical evidence is weak or absent.
Why Legal Representation Is Essential
Without an attorney, defendants face a process stacked against them. Police and prosecutors work daily with DUI cases and know how to make their evidence sound convincing. An unrepresented defendant has little chance of identifying errors in testing procedures or constitutional violations. By hiring a private Chicago criminal defense attorney, you gain access to strategic motions, expert witnesses, and legal advocacy focused solely on protecting your record and your future.
Even if this is your first DUI, the consequences extend beyond court. Employers, insurance companies, and licensing agencies often view DUI convictions harshly. For professional drivers, teachers, nurses, and others in regulated professions, a single conviction can end a career. A defense lawyer ensures that your case receives the level of investigation and advocacy necessary to avoid lifelong damage.
Penalties for DUI Convictions in Illinois
Illinois imposes harsh penalties for DUI convictions, which increase with each offense or aggravating factor. A first offense is a Class A misdemeanor, punishable by up to one year in jail and a $2,500 fine. A second offense carries mandatory jail or community service. A third or subsequent DUI is a felony, potentially carrying a prison term under 730 ILCS 5/5-4.5-45. Additional consequences include mandatory alcohol education, community service, and long-term license revocation.
For those under 21, Illinois has a zero tolerance policy under 625 ILCS 5/11-501.8, where any trace of alcohol can result in license suspension. CDL drivers face disqualification even for off-duty DUIs. The law leaves little room for error—another reason professional legal defense is indispensable.
Chicago Criminal Defense FAQs
Can weather or location affect my field sobriety test?
Yes. Snow, rain, uneven pavement, and bright lights can affect balance and coordination. Defense attorneys often use these factors to demonstrate unreliable testing.
Do I have to tell the officer about medical conditions before the test?
You’re not required to, but it helps your defense. If you have back, leg, or ear problems, those should be documented and later raised in court.
What happens if the officer didn’t record the stop?
The lack of video can hurt the prosecution. Courts expect Chicago police to preserve evidence whenever possible. Missing footage may justify dismissal or suppression.
Can I win my case even if I looked impaired on video?
Yes. Jurors and judges often understand that fatigue, nerves, or confusion can resemble intoxication. With strong legal arguments, these observations can be challenged effectively.
How does refusing field sobriety tests affect my case?
Refusal removes subjective evidence, which often helps your defense. However, you may still face administrative license suspension, which your lawyer can fight in a separate hearing.
What if my license is suspended before trial?
You can contest the suspension through a Petition to Rescind under Illinois law. Many clients regain driving privileges months before their criminal case concludes.
Why should I hire The Law Offices of David L. Freidberg?
Because we provide direct attorney access, decades of courtroom experience, and proven results in Cook, DuPage, Will, and Lake Counties. We prepare every case for trial and are available 24/7 to defend your rights.
Contact The Law Offices of David L. Freidberg
A field sobriety test is not the final word on your guilt or innocence. Many of these tests are flawed, misinterpreted, or illegally administered. The sooner you retain counsel, the stronger your defense will be. At The Law Offices of David L. Freidberg, we have decades of experience challenging field sobriety evidence and securing favorable outcomes in DUI cases across Chicago, Cook County, DuPage County, Will County, and Lake County.
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.