Pulled Over in Illinois? What to Know If a Traffic Stop Becomes a DUI Investigation

Several times I’ve been asked for my opinion on whether a driver should perform standardized field sobriety tests (SFSTs) and whether they should agree to blow into the breathalyzer if stopped for DUI or if stopped for a petty traffic offense that then leads to a DUI investigation. It is my opinion, based on defending drivers in Illinois charged with DUI for over 16 years, that if a police officer asks you to get out of your vehicle, they have already decided they are going to arrest you for DUI.

Therefore, if you’ve been drinking, you should refuse to perform SFSTs and should not blow into the breathalyzer at either the location of the stop (preliminary breath test "PBT") or in the breathalyzer offered at the station because you are giving the police additional evidence to use against you in court. There are consequences for refusing to submit to the breathalyzer offered at the police station; I will discuss these consequences below. It’s important to note the police can seek a search warrant to take a blood sample from you to determine your blood alcohol content (BAC) if you refuse to submit to the breathalyzer at the station.

What an Officer Needs to Stop You for a Petty Traffic Violation

Police don't need much to pull you over for a routine traffic violation. All they need is a reasonable suspicion that you’ve committed a traffic violation or are driving under the influence of alcohol. Most DUI matters in which I’ve represented clients resulted from an officer witnessing impaired driving (weaving between lanes, erratic driving, etc.), a minor traffic violation such as speeding or expired registration, or an accident.

After stopping a vehicle, an officer may smell an odor or alcohol or observe bloodshot glassy eyes and slurred speech. If the officer observes this, they’ll ask you if you’ve been drinking, and many people admit to having "a couple beers" whether they’ve actually had a couple beers or had 12. The officer will ask you for your driver’s license, proof of insurance, and proof of registration; you must provide these to the officer. If the officer asks you to get out of the vehicle, you must exit.¹ Your actions after exiting the vehicle will greatly affect whether you may win or lose at trial.

Some may disagree whether you must exit the vehicle if ordered by a police officer. Those disagreeing may argue that you don’t need to exit the vehicle if the officer doesn’t have a valid reason (reasonable belief) to ask you to do so. Let’s assume for the sake of argument that what the officer observed does not rise to the level of reasonable belief; the roadside is not the place to argue with the officer. They have the upper hand and, in my opinion, you can only make matters worse. Be polite and respectful, if you’ve been drinking refuse the tests, hire an experienced DUI lawyer, and fight the matter in court.

What an Officer Needs to Investigate You for DUI

Once you're pulled over, the officer needs additional justification to expand the stop into a DUI investigation. This is where things escalate. If the officer smells alcohol, sees open containers, notices slurred speech, glassy or bloodshot eyes, or you admit to drinking, that typically gives the officer reasonable suspicion to investigate further, meaning they can ask you to perform SFSTs. To arrest you for DUI, the officer needs probable cause, a higher standard than reasonable suspicion. This requires facts that would lead a reasonable officer to believe you committed the offense. This is where field sobriety tests and breath, blood, or urine tests come in: they are the primary tools officers use to build probable cause for an arrest, and later, evidence for a prosecution.

I stated above that it’s my opinion if an officer asks you to exit your vehicle, they have already decided you are going to be arrested for DUI. Officers do not like having drivers out of their vehicles during traffic stops. It’s less safe for them. Getting a driver out of the car works against officer safety, not for it. So when an officer asks you to step out of the vehicle during a routine stop, in my opinion, they believe you were driving under the influence of alcohol. It means the officer has already concluded they intend to arrest you for DUI, and stepping outside is not for your safety or theirs. It's to take SFSTs, which exist for one purpose: generating additional evidence to support the arrest and prosecution for DUI.

My Opinion: Refuse the SFSTs, Stay Silent, and Don't Blow

Here’s what I recommend:

• Decline the SFSTs. The walk and turn, one leg stand, and horizontal gaze nystagmus tests are marketed as objective, standardized measures. In practice, they are highly subjective, are graded by the same officer who suspects you of DUI, and are difficult for many sober people to perform correctly under stress, in poor lighting, on uneven pavement, in the cold, wearing dress shoes, or with pre-existing balance, inner ear, or physical conditions. These tests are also more difficult for older people and people who are overweight. If you've been drinking, in my opinion these tests add almost nothing for you and a great deal for the prosecution. There is no requirement under Illinois law that you perform these tests.
• Don't answer investigative questions. "Have you been drinking tonight?" and "How many drinks did you have?" are not small talk. They are evidence gathering questions asked by someone who has already decided how they intend to view your answer. You have a right to remain silent, and politely declining to answer is not, by itself, evidence of guilt.
• Limit walking and talking. You will most likely be on video and audio. Limit the amount you walk and talk because if you’re stumbling around, slurring your speech and otherwise sound intoxicated, this is evidence that will be shown during a trial. Be polite and respectful to the officer. Kindly inform him or her that you are not going to take any SFSTs and are not going to blow into the breathalyzer.
• Think carefully about the breathalyzer. This one is more complicated, and it's important I give you the full picture rather than just my opinion.

If you refuse to take the SFSTs and refuse to blow into the preliminary breath test (PBT), which is offered at the location of the traffic stop, then you are most likely going to be arrested for DUI; however, you’ve limited the amount of evidence the prosecutor will have to use against you at trial. This increases your chances of prevailing at trial.

The Breathalyzer Decision Is Different: Here's the Trade Off

Unlike SFSTs, refusing a breathalyzer in Illinois carries automatic, formal consequences under the state's implied consent law, and you should know the consequences before you're standing on the side of the road making that call. Under 625 ILCS 5/11-501.1, every licensed driver in Illinois is deemed to have already consented to chemical testing if lawfully arrested for DUI. Refusing this test after arrest triggers an automatic Statutory Summary Suspension of your driver's license, a one-year suspension for a first refusal, and a three-year suspension for a second refusal within five years, imposed by the Secretary of State separately from the criminal case, regardless of whether you're ultimately convicted of DUI. By comparison, a first-time offender who takes the test and fails faces only a six-month suspension. In other words, refusal carries a longer administrative penalty than failing.

That said, refusal does mean the prosecution has no specific BAC number to work with. Without a breath test result, the state generally cannot charge you under the "per se" DUI statute for driving with a BAC of 0.08% or higher, though prosecutors can still pursue a charge for driving while impaired based on the officer's observations and other evidence. This is a real trade off, not a free pass. Refusal can still lead to arrest, and the case can still be prosecuted using the officer's observations, dashcam or bodycam footage, and any refusal to perform SFSTs.

This is a decision with real consequences either way, and it's genuinely fact specific. How much you had to drink, your driving record, whether this is a first offense, and your tolerance for a guaranteed license suspension versus the risk of a higher BAC number in evidence, all matter. This is the point in the stop where getting a DUI lawyer on the phone, if you can, is worth more than anything else in this post. If you do receive a statutory summary suspension, you can file a petition to rescind the suspension and try to get it thrown out.

The Bottom Line

If you're stopped for a minor traffic violation and the officer starts asking about alcohol, understand what's happening: the officer needs only reasonable suspicion to stop you, and once they smell alcohol or see signs of impairment, they're building toward probable cause for an arrest. In my opinion, being asked to exit the vehicle is usually a sign that decision has already been made. What you do next, particularly around field sobriety tests, questions, and the breathalyzer, can significantly affect what evidence exists against you later. Contact us today for a free consultation!

This post reflects my professional opinion based on my experience practicing Illinois criminal and civil litigation and is not legal advice for any particular situation. If you've been arrested for DUI in Illinois, the facts of your specific stop matter enormously, and you should speak with a DUI attorney as soon as possible.