Updated March 2025

In a typical traffic stop for suspicion of DUI, a police officer may ask a driver to blow into a breathalyzer device. But can you refuse a breathalyzer test, and should you? And, what will happen if you do?

Our DUI attorneys at Driver Defense Team have put together this guide to give you the answers you need. We’ll explain your options when it comes to refusing a breathalyzer test in Illinois and how your decision can affect your case.

It’s important to know that if you’re facing a DUI charge, you should contact a Chicago DUI attorney as quickly as possible about your case. We can provide personalized legal advice and get you the best possible outcome. The sooner you act, the better the result can be.

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Preliminary versus Evidentiary Breath Tests in Illinois

If you look up whether you can refuse a breathalyzer in Illinois, you might find a lot of confusing, and even conflicting, information. One website might tell you that refusing a test can help your case, as it gives prosecutors less evidence. Then, you might click on another website only to read that refusing a test can actually be used against you in court.

So, which is it?

To understand the law around refusing a breathalyzer in Illinois and the potential penalties, we need to explore the difference between preliminary and evidentiary breath tests.

Preliminary Breathalyzer Tests

If you’re pulled over by the police for suspicion of a DUI in Illinois, the officer may ask you to take a breathalyzer test. Many patrol cars have a portable breath testing device for screening drivers suspected of alcohol impairment. They’ll get a handheld device and ask you to blow into the mouthpiece to measure your blood alcohol content (BAC).

Evidentiary Breathalyzer Tests

An evidentiary breathalyzer is a stationary machine used at a police station, often called an Intoxilyzer. Like a preliminary test, an evidentiary breathalyzer records a person’s BAC by analyzing a breath sample.

An evidentiary breath test must be conducted by a law enforcement officer who has been certified to operate a breathalyzer device. Without that certification, an Illinois DUI attorney can challenge the breathalyzer results in court.

What’s the Difference?

As preliminary breathalyzers are designed for quick screening in the field, they are not as accurate as evidentiary breathalyzers. But that’s not the only difference.

The other key differences between these two types of breath tests are how the results can be used against you in court and the penalties for refusing them.

Preliminary breathalyzer test results are not typically admissible in court, while the results of an evidentiary test are. But, a preliminary breathalyzer result can give police officers probable cause. In other words, if you take a roadside breathalyzer and test positive (.08 BAC or higher) or refuse to give a sample, the police can arrest you for a DUI. However, there are other ways of getting probable cause. So, it doesn’t necessarily mean that if you refuse the preliminary breathalyzer test that you’ve avoided any possibility of arrest. 

The penalties for refusing a breathalyzer vary based on whether you refuse a preliminary or evidentiary test and if you’ve been convicted of a DUI before.

These penalties apply because of a concept called implied consent.

Can You Refuse a Breathalyzer Test in Illinois?

What Is Implied Consent?

Illinois law recognizes that driving is a privilege, not a right — and that privilege can be taken away at any time if you don’t keep up your end of the bargain.

Part of this “agreement” is that by receiving a driver’s license in Illinois, you consent to chemical testing if the police suspect you are driving under the influence.

Implied consent doesn’t mean you have to take a breath test if you’re asked to — you can refuse. But because you’ve given implied consent by driving on the road, you’ll be penalized automatically.

The Penalties for Refusing a Breathalyzer Test

The penalty for refusing an evidentiary breath test is a one-year license suspension, called a “statutory summary suspension.”. If you’ve been arrested for a DUI in the past five years, your license will be suspended for three years.

This is an administrative penalty separate from your criminal DUI case.

How Refusing a Breathalyzer Can Affect Your Criminal Case

If you’re pulled over by the police and they suspect you’ve been drinking, you can:

  • Take the roadside breathalyzer test. If you have a BAC of .08 or higher, you’ll be arrested for DUI and receive a statutory summary suspension of six months.
  • Refuse the roadside breathalyzer.  The officer will likely still arrest you after building their case around you.

Then, when you get to the police station, a certified law enforcement officer will ask you to take an evidentiary test.

 It’s true that the evidentiary test is admissible in court and that the prosecutor will likely argue that you refused the breathalyzer test because you were trying to hide the fact that you were over the limit. However, giving concrete evidence like a breath test is a much bigger obstacle to your case than fighting the argument that you refused the breath test to hide that you were over the limit.

So What Should You Do?

You can refuse a breathalyzer exam, but should you? Every situation is unique, so there is no simple yes-or-no-rule that applies to every case. Let’s look at some scenarios where you might be better off taking the test, and when your best option is to refuse.

You Haven’t Had a Drink

If you’re certain you haven’t drunk any alcohol, taking the test is the better choice. Even if the police still arrest you because they suspect you might be intoxicated, an evidentiary test provides admissible evidence that you’re not drunk, and the state’s case likely won’t hold up in court.

Remember, though, that alcohol stays in your system long after your last drink. Breathalyzers can detect alcohol on the breath for up to 24 hours.

We have also seen cases where our client has blown .00 on the breath test yet they still get arrested under an officer’s suspicion that they are on drugs.

You’re Not Sure or You’re Over the Limit

If you’re not sure what your results will be, or you know you’ve had a drink or two and that you might be over the limit, it’s always better to refuse the breathalyzer test.

Taking the breathalyzer and testing positive will net you a license suspension of six months instead of 12 if you were to refuse, but taking the test also gives prosecutors evidence they can use against you in a DUI prosecution.

If you also agree to do the Standardized Field Sobriety Tests (SFSTs) and the police determine that you had trouble balancing, counting, or holding a steady gaze (even if there’s another explanation), it’s even more evidence the state can use to prove its case against you.

That’s why, as a rule, we recommend refusing both the SFSTs and the breathalyzer test.

Refusing to take a breathalyzer test may result in a longer suspension, but that’s always significantly preferable to a DUI conviction.

A DUI conviction will result in a license revocation, which is a bigger mountain to climb than a license suspension. Whereas a suspension means a defined time of loss in driving privileges, a revocation means an indefinite loss of driving privileges. The road to getting your driving privileges back after a revocation is a long and difficult one. We know this because we’ve helped many clients do this, often going 5, 10, 25 years or more before getting their driver’s license back because of how complex the process is.

What If I’ve Already Taken a Breathalyzer?

You don’t have the right to speak to a DUI attorney before a breathalyzer test, so you may have taken it and tested positive.

In this case, it becomes even more important to consult an attorney as soon as possible. First, there’s the administrative penalty to deal with — your statutory summary license suspension.

This won’t kick in straight away. The Secretary of State will typically take your driving privileges away 45 days after your arrest.  This gives you time to challenge your suspension. The sooner you speak to a lawyer, the more time they have to challenge your suspension so you can stay on the road once your suspension starts. You will want to give your attorney as much time as possible to fight your suspension.

Then, there’s the criminal case of DUI. Your attorney will develop a defense strategy to get you the best result. This might mean challenging the evidence the state has to get the DUI charge dropped.

For example, if any of the following are true, the prosecution has a weaker leg to stand on:

  • The Field Sobriety Tests were not conducted in accordance with the National Highway Traffic Safety Administration (NHTSA).
  • Law enforcement did not give you an opportunity to refuse the evidentiary breathalyzer.
  • The police didn’t have probable cause for pulling you over to begin with, meaning there was no way they could have reasonably suspected you were under the influence.
  • The evidentiary breathalyzer was not done by a certified law enforcement officer.

These are just some of the ways we’ve won cases for our clients. In some cases, the best strategy might not be to deny that you were intoxicated but to reduce the charges or negotiate a court supervision sentence. This can be preferable for first-time DUI offenders, as it means you won’t face jail time. Completing court supervision also means the DUI won’t be entered as a conviction on your record.

The best result for one person will not be the same for another. Many factors can influence your defense strategy, including whether you’ve been convicted of a DUI before or you’re a commercial driver. That’s why it’s crucial to work with an attorney who can look at your unique situation and develop a customized game plan to get the best result for you.

The Most Important Thing: Avoiding a DUI Conviction

You might want to cooperate with law enforcement. You might think a six-month license suspension is better than a year off the road. Or you might believe you weren’t intoxicated and there’s no way you’d fail a breathalyzer.

These are all valid reasons for taking a breathalyzer test. But those things don’t matter to prosecutors — their goal is to secure a DUI conviction.

A DUI attorney can help you overcome a DUI charge, but that doesn’t take away from the fact that a DUI is a serious charge.

Typically, a first DUI offense in Illinois is a Class A misdemeanor. The maximum penalty is up to one year in county jail and a fine of up to $2,500 plus court costs. Jail time is rare for a first offense, but it can happen.

In most cases, only drivers charged with a third or subsequent DUI face felony charges. But, even a first-time DUI can be charged as a felony — such as if a driver caused an accident resulting in severe injury or death or was driving with a suspended license. Felony charges carry more severe penalties.

And, a DUI conviction will go on your criminal record, which can have a long-term effect on your job prospects, schooling, and travel plans.

Avoiding the penalties of a DUI conviction is vital. The best way to do that is to give the state as little evidence as possible for them to prove their case — including breathalyzer results.

When Should You Contact a DUI Attorney?

If you are placed under arrest and charged with driving under the influence anywhere in or near the Chicago area, you must arrange — as quickly as possible — to speak with an Illinois DUI lawyer.

Whatever your situation, we will work to achieve the best possible outcome.

When you choose Driver Defense Team, you don’t just hire one lawyer. You get our entire team working on your case. That’s over 114 years of experience you can benefit from. Get in touch today to explore your options. You can call, text, submit an online form, or pop into our offices in Chicago, DuPage County, or Cook County. We’ll develop a custom GamePlan to get you the right result.

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