Getting pulled over and asked to blow into a breathalyzer is one of the most stressful moments a driver can face. Whether you should refuse, and what actually happens if you do, depends on which test you are asked to take, what state you are in, and whether you have already been arrested. This guide breaks down the real consequences in plain English.

There are two different "breathalyzers"

The single most important thing to understand is that the word "breathalyzer" covers two very different tests, and the rules for refusing them are not the same.

  • The roadside preliminary breath test (PBT). This is the small handheld device an officer may ask you to blow into before arrest, on the side of the road. It is a screening tool used to help build probable cause for a DUI arrest.
  • The evidentiary breath test. This is the larger, calibrated machine (often an Intoxilyzer or DataMaster) at the police station or jail, given after a DUI arrest. This is the test your state's implied-consent law is really about, and the test with serious refusal penalties.

Confusing the two is the most common mistake drivers make. Refusing the first is usually low-risk. Refusing the second can cost you your license.

Refusing the roadside PBT

In most states, the handheld roadside breath test is voluntary for adult drivers, and refusing it carries little or no penalty by itself. The same is generally true of field sobriety tests (the walk-and-turn, one-leg stand, and eye-tracking tests), which are also voluntary almost everywhere. These roadside exercises mainly exist to give the officer evidence against you, so politely declining them deprives the officer of that evidence.

There are important exceptions. A handful of states attach a small fine or a license point for refusing a PBT. Drivers under 21 and commercial (CDL) drivers face much stricter rules under zero-tolerance and federal commercial-driver standards, where even a roadside refusal can trigger a suspension or disqualification. The Fourth Amendment governs all of this: an officer still needs reasonable suspicion to detain you and probable cause to arrest you, and declining a voluntary test does not, by itself, create probable cause.

Every state has an implied-consent law. By driving on public roads, you are deemed to have agreed in advance to submit to chemical testing (breath, blood, or urine) if you are lawfully arrested for DUI on probable cause. This is the legal hook behind the post-arrest evidentiary breath test. Once you have been arrested and read the implied-consent warning, refusing the official test triggers its own set of penalties that are separate from, and stacked on top of, the underlying DUI case.

What happens if you refuse the evidentiary test

Refusing the post-arrest evidentiary test typically sets off several consequences at once:

  • Administrative license suspension (ALS). The state DMV or motor-vehicle agency can suspend or revoke your license simply for refusing, regardless of whether you are ever convicted of DUI. In most states the suspension for refusing is longer than the suspension for taking the test and failing.
  • Fines and reinstatement fees. Many states impose a separate civil penalty for refusal, plus the usual reinstatement costs.
  • Refusal used as evidence at trial. In South Dakota v. Neville, the Supreme Court held that using your refusal against you at trial does not violate the Fifth Amendment right against self-incrimination. Prosecutors routinely argue that refusal shows "consciousness of guilt." A few states, however, bar refusal evidence by statute.
  • Ignition interlock and longer sentences. Refusal can mean a mandatory interlock device and enhanced penalties if you are later convicted.

Can you be criminally charged just for refusing?

Here the law turns on what kind of test it is. In Birchfield v. North Dakota (2016), the Supreme Court drew a sharp line. A breath test is a relatively minor intrusion that qualifies as a search incident to arrest, so police do not need a warrant, and a state may make it a crime to refuse a warrantless breath test after a lawful DUI arrest. A blood draw is far more intrusive, so it generally requires a warrant or a valid exception, and a state cannot make it a crime to refuse a warrantless blood test.

Two related cases fill in the picture. Missouri v. McNeely held that the natural dissipation of alcohol in the bloodstream is not automatically an exigent circumstance justifying a warrantless blood draw, so police usually need a warrant for blood. Mitchell v. Wisconsin carved out an exception for unconscious drivers, where a warrantless draw is often allowed. The practical upshot: in many states refusing the breath test can be a crime, while refusing a warrantless blood draw cannot, though police can then get a warrant and take your blood anyway.

Refuse or fail: is there a strategy?

There is no one-size-fits-all answer, and this is exactly where talking to a local DUI lawyer matters. In some states, the administrative penalty for refusing is so severe (and refusal can still be used against you) that taking the test is the lesser harm. In others, refusing denies the prosecution a hard BAC number, which can weaken a borderline case. The right move depends on your prior record, your state's specific penalties, and the facts of the stop.

A state-by-state snapshot

Penalties for refusing the evidentiary test vary widely, and they change often, so treat these as illustrations rather than current legal advice:

  • New York: a first refusal generally means about a one-year license revocation plus a civil penalty, separate from the DUI case.
  • New Jersey: refusal is treated as its own offense with license consequences and a mandatory ignition interlock.
  • Pennsylvania: a first refusal commonly carries a 12-month suspension and can trigger enhanced criminal penalties on conviction.
  • New Hampshire: a first refusal typically brings a 180-day suspension.
  • Massachusetts: a first refusal usually means a 180-day suspension, and notably, Massachusetts law makes the refusal itself inadmissible against you at trial.

Always confirm the current rule in your state, because legislatures revise these statutes frequently.

What to do if you are asked to test

Stay calm and respectful. You can ask the officer whether the test is the voluntary roadside PBT or the official post-arrest test, and you can ask whether you are free to leave. You always keep the right to remain silent about where you were or how much you drank. If you are arrested and unsure what to do, say clearly that you want to speak with a lawyer before deciding, and do not physically resist any test the officer is legally carrying out, especially a blood draw taken on a warrant.

This article is general legal information, not legal advice. DUI and implied-consent laws differ by state and change often, and your situation may turn on specific facts. Talk to a licensed DUI attorney in your state about your case.