Can I Refuse a Breathalyzer Test During a DUI Stop in Colorado?

It’s the question nearly every driver asks when those blue and red lights flash behind them: Do I have to blow?

The answer depends on timing. Before an arrest and after an arrest are two completely different legal situations in Colorado. Getting them confused can cost you your license, your freedom, or both.

Here’s what Colorado law actually says about refusing a breathalyzer, and what happens when you do.

Pre-Arrest vs. Post-Arrest

This is the most important distinction in Colorado DUI law, and most drivers don’t know it exists.

Before you’re arrested, the officer may ask you to take a Portable Breath Test (PBT) on the side of the road. This is the handheld device officers use during traffic stops.

If you’re 21 or older, you can refuse this roadside breath test without penalty. The results aren’t even admissible in court because the devices aren’t considered reliable enough. The purpose of the PBT is to help the officer establish probable cause to arrest you.

Your refusal of the roadside PBT cannot be used against you in court under C.R.S. § 42-4-1301.

After you’re arrested, the rules change completely. Colorado’s Express Consent law kicks in, and refusing a chemical test (breath or blood) triggers serious consequences.

What is Colorado’s Express Consent Law?

Under C.R.S. § 42-4-1301.1, every person who drives a motor vehicle on Colorado roads is considered to have already given consent to a chemical test. The law applies when a police officer has probable cause to believe you were driving under the influence of alcohol, drugs, or both.

In plain language: by choosing to drive in Colorado, you’ve already agreed to be tested if you’re lawfully arrested for DUI.

This isn’t implied consent in the casual sense. The Colorado Department of Revenue enforces this law through automatic administrative penalties the moment you refuse.

What Happens If You Refuse a Breathalyzer After Arrest?

Refusing a chemical test after a DUI arrest sets off a chain of consequences that exist entirely separate from any criminal DUI charges you may face.

Immediate consequences of refusal:

• Automatic license revocation for one year on a first refusal. The officer will confiscate your license on the spot and issue a temporary 7-day driving permit.
• Two-year revocation for a second refusal.
• Three-year revocation for a third or subsequent refusal.
• Persistent Drunk Driver (PDD) designation, even if this is your first DUI-related incident. This label carries its own set of requirements.

The PDD designation means you must:

• Complete a Level II alcohol education and therapy program
• Install an ignition interlock device (IID) on your vehicle for at least two years
• Obtain SR-22 high-risk insurance
• Meet stricter requirements for license reinstatement

These are administrative penalties imposed by the DMV. They happen whether or not you’re ever convicted of DUI in criminal court.

Can Your Refusal Be Used Against You in Court?

Yes. Colorado law allows prosecutors to introduce your refusal as evidence in your DUI trial. The argument is straightforward: you refused because you knew you were impaired.

Preliminary data from 2025 shows that 44% of DUI arrests in Colorado involved the refusal of a blood or breath test. That’s a significant number, and prosecutors are well-practiced at turning refusals into convictions.

A skilled defense attorney can challenge the circumstances around the refusal, but the refusal itself is admissible. That’s a fact you need to understand before deciding to refuse.

You Have 7 Days to Challenge a License Revocation

After a refusal, you have just seven days from the date of your arrest to request an administrative hearing with the Colorado DMV. If you miss this deadline, the revocation goes into effect automatically, and you lose the right to challenge it.

At the hearing, your attorney can argue that:

• The officer didn’t have probable cause for the arrest
• The officer failed to properly advise you of the consequences of refusal
• The testing request didn’t comply with Colorado law
• The circumstances of the stop were unlawful

Winning this hearing can save your driving privileges. But you have to act fast.

Should You Refuse Roadside Sobriety Tests, Too?

Field sobriety tests (FSTs) are different from chemical tests. These are the physical tests the officer asks you to perform on the side of the road, such as:

• Walk-and-turn
• One-leg stand
• Horizontal gaze nystagmus (eye tracking)

You can refuse these tests without triggering Express Consent penalties. Field sobriety tests are voluntary, and they are notoriously subjective. Medical conditions, fatigue, uneven pavement, poor lighting, and even the type of shoes you’re wearing can all produce results that look like impairment.

The officer may still arrest you based on other observations, such as the smell of alcohol, slurred speech, or erratic driving. But refusing the FSTs means there’s less evidence for the prosecution to work with.

Can Officers Force a Blood Draw?

Here’s something many drivers don’t realize: even if you refuse a breathalyzer after arrest, the officer can seek a warrant for a forced blood draw. Colorado courts have upheld this practice.

If a judge issues a warrant based on probable cause, officers can restrain you and draw your blood regardless of your consent. So refusing the test doesn’t guarantee the state won’t get a BAC reading anyway.

It just means you’ll face the refusal penalties on top of whatever the blood test reveals.

When Refusal Might Be a Strategic Decision

There are limited situations where refusing might make tactical sense, but those situations are rare.

If you genuinely believe your BAC is extremely high and a conviction would carry devastating consequences, some attorneys advise that the administrative penalties of refusal may be less damaging than a criminal conviction with a very high BAC.

That said, this is a gamble. The refusal penalties are automatic and severe. And with forced blood draws becoming more common, refusing doesn’t guarantee your BAC stays hidden.

The safest legal advice is simple: don’t drink and drive. But if you find yourself arrested, the decision to refuse or submit should be made with a clear understanding of the consequences on both sides.

Defenses After a DUI Stop in Colorado

Whether you refused or submitted to testing, an experienced DUI attorney can challenge the prosecution’s case. Common defense strategies include:

• Improper traffic stop. If the officer lacked reasonable suspicion to pull you over, everything that followed may be thrown out.
• Breathalyzer calibration issues. These machines require regular maintenance and calibration. If the device wasn’t functioning properly, the results may be unreliable.
• Blood test errors. Contamination, improper storage, or breaks in the chain of custody can undermine blood test evidence.
• Rising BAC defense. Your blood alcohol may have been below the legal limit while you were actually driving but rose above 0.08% by the time testing occurred.
• Miranda violations. Statements made during custodial interrogation without Miranda warnings may be inadmissible.

Talk to a Colorado DUI Defense Lawyer Before It’s Too Late

If you’ve refused a breathalyzer test in Colorado, the clock is ticking. You have seven days to request a DMV hearing, and every day you wait gives the prosecution more time to build their case.

At Dawson Law Office, we’ve handled DUI cases across Colorado. We know how to challenge improper stops, flawed testing procedures, and the prosecution’s use of refusal evidence. Whether your goal is to save your license, fight the criminal charges, or both, we’re prepared to help.

Contact us today for a free consultation. Your future depends on what you do right now.