Illinois Police Say I Failed a Roadside Sobriety Test When I Did Not

 Posted on July 25, 2025 in DUI

Being told you failed a roadside sobriety test when you were completely sober is a frustrating and serious situation. In Illinois, field sobriety tests are often used to justify DUI arrests, but they are not always accurate or fairly administered. If you believe you were wrongfully accused of DUI based on a faulty roadside test, you should understand how these tests work, why they sometimes fail, and how to fight back in court. Our Naperville, IL DUI defense attorney can help.

Reasons Someone Might Fail a Roadside Sobriety Test Even When Sober

Sober people can fail field sobriety tests for several reasons that have nothing to do with alcohol or drug use. Medical conditions, such as inner ear disorders, arthritis, or past injuries, can interfere with balance and coordination. Anxiety, fatigue, or unfamiliarity with the test instructions can also lead to poor performance.

Environmental factors play a role as well. Uneven pavement, poor lighting, and bad weather can all negatively affect how someone performs on a test like the walk-and-turn or one-leg stand. In some cases, officers may misinterpret normal behavior as signs of impairment due to their own biases or lack of training. 

Will a Failed Field Sobriety Test Lead to a Conviction in Illinois?

Field sobriety tests do not offer scientific proof of intoxication. Even when administered properly, their accuracy is limited. According to 625 ILCS 5/11-501.2, the results of these tests can be admitted in court, but they are not conclusive. Officers must follow standardized procedures, and failing to do so may render the test results unreliable.

The stop itself must also be legal. Illinois law, under 725 ILCS 5/107-14, states that police must have reasonable suspicion to conduct a traffic stop. If the stop was unlawful, any evidence gathered afterward, including field sobriety results, may be suppressed.

In some cases, chemical testing follows the roadside tests. Statute 625 ILCS 5/11-501.4 outlines the use of chemical test results, but only if they were properly administered and legally obtained. Field sobriety results alone are not enough to support a DUI conviction.

Challenging Field Sobriety Tests in Illinois Court

If you are facing a DUI charge after failing roadside sobriety testing, your defense attorney can raise several arguments to question the results. Some common examples include:

• Incorrect administration: You may argue that the officer did not follow the proper protocols of the NHTSA for administering the tests.

• Unfair conditions: If the weather, road surface, or lighting made the test harder than normal, you can argue that the conditions likely interfered with your ability to perform.

• Medical issues: If you have a health condition that affects balance, coordination, or vision, you could argue that it may have affected your tests.

• Misunderstood instructions: If the officer did not clearly explain the test, you may have failed because of a lack of understanding.

• Illegal stop: If the officer lacked a valid reason to pull you over in the first place, your attorney may challenge all the evidence against you.

Schedule a Free Consultation With a Naperville, IL DUI Defense Attorney

Attorney Philip R. Nathe at Law Office of Philip R. Nathe is a former Assistant State’s Attorney in DuPage County, and he understands the criminal process from both sides. He uses that knowledge to anticipate the prosecution’s strategy and fight for your best interests. Clients praise Attorney Nathe and our team for our professionalism, responsiveness, and ability to get results. To schedule your free consultation with our experienced and aggressive Naperville, IL DUI defense lawyer, call 630-416-7600 today.