Yes. In Illinois, field sobriety tests (the roadside physical tests an officer asks you to perform, like walking a straight line heel-to-toe or standing on one leg) are voluntary. You can decline them without committing a crime or automatically losing your license. There is no law in Illinois that forces you to do them, and no direct license penalty for saying no.
That’s the short answer, but it’s incomplete in a way that matters. A “field sobriety test” is not the same thing as a “breathalyzer,” and the two follow opposite rules. This article walks through how a field sobriety test differs from the breathalyzer, what the field sobriety tests actually are, whether refusing them can be used against you, whether the officer can still arrest you after you refuse, and whether refusing was the right move.
Is a field sobriety test the same thing as the breathalyzer?
No, and this is the single most important thing to understand, because Illinois law treats them as two completely different categories with opposite consequences.
Field sobriety tests are the physical, roadside tests: the walk-and-turn, the one-leg stand, and the eye-tracking test where the officer moves a pen or finger and watches your eyes. These are voluntary. Illinois’s “implied consent” law is the rule that says by driving on Illinois roads you’ve already agreed to certain testing. It applies only to chemical tests, not to these physical roadside tests (625 ILCS 5/11-501.1). Declining them carries no automatic license suspension.
The breathalyzer is a chemical test, and the one that matters here, the evidentiary breath test given after arrest, is covered by implied consent. Refusing that one is still legal, but it triggers an automatic suspension of your driving privileges. Same word in your head, two different machines, two different sets of rules. Keep that fork in mind, because everything below depends on it.
What are the field sobriety tests, exactly?
They’re a set of three standardized roadside tests an officer uses to build a case that you’re impaired. Knowing what they are helps you understand why they’re so easy to challenge, and why they’re voluntary in the first place.
The three standardized field sobriety tests recognized in Illinois are:
- The walk-and-turn: take nine heel-to-toe steps along a line, turn, and come back, while following instructions.
- The one-leg stand: stand with one foot about six inches off the ground and count until told to stop.
- The horizontal gaze nystagmus (HGN) test: the officer moves an object side to side and watches your eyes for involuntary jerking.
Illinois allows officers to use these federally standardized tests during a DUI investigation (625 ILCS 5/11-501.2(a-5)). But the results are far from ironclad. The HGN eye test, in particular, can only be offered to suggest alcohol consumption and possible impairment. An officer cannot use it to claim a specific blood-alcohol number (People v. McKown, 236 Ill. 2d 278 (2010)). On top of that, involuntary eye-jerking has more than 40 causes that have nothing to do with alcohol. The walk-and-turn and one-leg stand are treated as ordinary officer observations rather than science (People v. Bostelman, 325 Ill. App. 3d 22 (2001)). That means they’re vulnerable to every real-world factor: your age, weight, injuries, inner-ear problems, fatigue, footwear, the sloped shoulder of a road, poor lighting, cold weather, and the flashing lights of the squad car right behind you. In other words, these are subjective tests you can fail stone-cold sober.
If I refuse the field sobriety tests, can that be used against you in court?
Yes, a prosecutor can bring up your refusal at trial. But it is not a crime, it carries no automatic license suspension, and you’re entitled to explain why you declined.
Illinois courts have held that a refusal to perform field sobriety tests can be admitted as evidence. But the defendant may offer explanations for it (People v. Roberts, 115 Ill. App. 3d 384 (1983)). That matters, because it lets you put your reasons in front of the jury: that you’d been told the tests are optional, that you have a bad knee or an inner-ear condition, that you didn’t trust doing gymnastics on the shoulder of a highway at night in traffic. A refusal is a talking point for the State, not a conviction. Weigh that against what a failed set of tests hands the prosecutor: a trained officer testifying, step by step, about everything you did wrong.
If I refuse, can the officer still arrest me for DUI?
Yes. Declining the field sobriety tests takes away evidence the officer would have used. But it doesn’t tie their hands; they can still arrest you based on everything else they observed.
To arrest you for DUI, an officer needs “probable cause,” enough facts to lead a reasonable person to believe you were driving under the influence. Illinois courts have found that probable cause is “commonly established” by things like the odor of alcohol, slurred speech, and red or glassy eyes, combined with the officer’s testimony (People v. Wingren, 167 Ill. App. 3d 313 (1988)). None of that requires you to have done a single field sobriety test. So refusing the tests is not a magic escape hatch. It’s one strategic choice that removes one category of evidence, while the officer may still have plenty of other grounds to make the arrest.
Here’s the flip side worth knowing: refusing isn’t automatically the winning move in every case either. In People v. Day, 2016 IL App (3d) 150852, a driver who smelled of alcohol, had bloodshot eyes and slurred speech, and admitted drinking still beat the arrest, because he passed the field sobriety tests and drove nearly perfectly. Sometimes doing the tests and doing them well is what saves you. Which is exactly why there’s no one-size-fits-all answer, and why the “should I have refused” question below is a judgment call.
So should you refuse? Was it the right call?
There’s no universal answer. It depends on which test, what you’d already said and done, your likely blood-alcohol level, and whether you have a prior DUI. Anyone who gives you a flat “always refuse” or “always comply” is guessing.
The field sobriety tests are subjective and easy to fail sober, so declining them often makes strategic sense. But as People v. Day shows, passing them can also be what defeats the arrest. The breathalyzer is a harder call. Refusing keeps a specific number out of the State’s hands, but it costs you a longer suspension and the first-offender driving permit. The right move turns on facts specific to your stop: how much other evidence the officer already had, whether the machine and procedures were even done correctly, and what a suspension would do to your life. This is the kind of complicated decision that can’t be reliably made from a search result. That’s the honest reason to get a defense attorney’s read on your actual case rather than a general rule.
How DRD Law can help
The questions in this article aren’t abstract: a DUI case is often won or lost on details like whether the field sobriety tests were administered correctly, whether the officer really had probable cause to arrest, and how a refusal gets explained to a jury. That’s evidence-driven work, and it’s the approach DRD Law, LLC is built around.
Founding partner David R. Drwencke has handled 565+ criminal defense cases over more than a decade and spent nearly seven years as a judicial law clerk in circuit court, watching hundreds of trials and learning firsthand how judges weigh exactly these arguments. He’s admitted to the Illinois, Michigan, and D.C. bars, has been named an Illinois Super Lawyers Rising Star every year from 2019 through 2026, holds Martindale-Hubbell’s AV Preeminent peer rating, and was recognized as an Elite Lawyer in 2026. The firm also gives clients a proprietary mobile app for real-time case tracking and 24/7 attorney communication.
DRD Law is located at 332 S. Michigan Avenue, Suite 900, Chicago, IL 60604, and can be reached through drdlawllc.com. If you’ve been arrested for DUI, the sooner you have someone reviewing how the stop and the tests were handled, the better.
This article is general legal information about Illinois law, not legal advice. Every DUI case turns on its own facts, and reading this does not create an attorney-client relationship between you and DRD Law, LLC. For advice about your specific situation, speak with a licensed Illinois attorney.
