Refusing a field sobriety test is legal in every state, and it carries no fine, no license suspension, and no criminal charge on its own. These roadside exercises are voluntary. That said, declining them will not necessarily end the stop: an officer who already suspects you of impaired driving can arrest you based on other observations, and once you are under arrest, the rules for the chemical test that follows are entirely different.
What Officers Ask You to Do at the Roadside
The National Highway Traffic Safety Administration endorses three standardized tests that officers use at traffic stops.1National Highway Traffic Safety Administration. DWI Detection and Standardized Field Sobriety Test Resources The Horizontal Gaze Nystagmus test has the officer move a pen or finger across your field of vision and watch for involuntary jerking of your eyes. The Walk-and-Turn asks you to take nine heel-to-toe steps along a line, turn on one foot, and walk back. The One-Leg Stand asks you to raise one foot about six inches off the ground and count aloud for roughly 30 seconds.
Each one forces you to split your attention between a physical task and a set of instructions, which is harder when a person is intoxicated. But these are screening tools, not chemical measurements. They flag suspicion; they do not prove anything on their own.
Why You Can Say No Without a Penalty
Field sobriety tests are investigative, not mandatory. No state imposes fines, license points, or an automatic suspension for declining to perform them. You are not required to give physical evidence of your own impairment at the roadside, and refusing is not a crime.
This surprises people because they confuse field sobriety tests with the chemical test that comes after arrest. Those are governed by separate legal frameworks. An officer may push hard for your cooperation, and the request can sound like an order, but you are within your rights to politely decline.
What Happens If You Refuse
Refusing does not mean you go home. Officers regularly arrest drivers who decline field sobriety tests based on the evidence they already have. Erratic driving, the smell of alcohol, slurred speech, bloodshot eyes, open containers, and your general demeanor during the stop can establish probable cause for a DUI arrest without any test results.
Your refusal itself can also be used against you later. Courts in many jurisdictions allow prosecutors to tell the jury that you declined the tests and to argue this reflects a “consciousness of guilt.” It is not a conviction, but it is a piece of evidence working against you. The trade-off is the core of the decision: perform the tests and risk handing officers stronger evidence, or refuse and give them a thinner file to build on.
Most DUI defense attorneys lean toward refusal for that reason. Officers who ask you to perform the tests usually already suspect impairment, and showing indicators only strengthens the case against you. If you refuse, they may still arrest you, but the state has less to work with.
Why Sober People Sometimes Fail These Tests
The tests are less reliable than most drivers assume. NHTSA’s own 1998 field study found the HGN test correctly classified impaired drivers about 88% of the time, the Walk-and-Turn about 79%, and the One-Leg Stand about 83%.2National Institute of Justice. Validation of the Standardized Field Sobriety Test Battery at BACs Below 0.10 Percent Even the best-performing test misclassifies roughly one in eight people, and real-world roadside conditions tend to be worse than study conditions.
The HGN test is especially vulnerable to false positives. NHTSA training materials acknowledge that inner ear disorders, brain tumors, brain injuries, epilepsy, and certain medications can produce the same eye jerking an officer is looking for.3National Highway Traffic Safety Administration. Horizontal Gaze Nystagmus – The Science and the Law A small number of people show visible nystagmus naturally, with no substance or condition involved.
Balance-based tests raise similar problems. Arthritis, vertigo, Parkinson’s disease, multiple sclerosis, low blood sugar, obesity, and age over 65 can all degrade performance in ways that look like intoxication. So can the shoes you are wearing or the slope of the shoulder. A sober person has plenty of ways to look impaired.
Chemical Tests After Arrest Are a Different Story
Once you are placed under arrest for DUI, the legal picture changes. Every state has an implied consent law, meaning that by driving on public roads, you have already agreed in advance to submit to a chemical test — breath, blood, or urine — if lawfully arrested for impaired driving. Refusing that test triggers automatic penalties, separate from the criminal case.
One point of confusion matters here. Many officers carry a portable breath device and may offer a roadside breath screening before any arrest. That preliminary test is not the same as the evidentiary chemical test given after arrest, usually at a station or hospital. In most states, drivers over 21 who are not on DUI probation can refuse the roadside screening without triggering implied consent penalties. The penalties attach to refusing the post-arrest evidentiary test. If you are unsure which one you are being asked to take, ask the officer directly whether you are under arrest.
Penalties for Refusing the Chemical Test
Refusing the post-arrest chemical test triggers administrative sanctions that take effect regardless of whether you are ever convicted of DUI. The most common is an automatic license suspension, typically six months to one year for a first-time refusal, longer for repeat refusals. Because these suspensions are administrative rather than criminal, they move quickly.
Several states also require an ignition interlock device on your vehicle before any driving privileges can be restored, even after a first refusal. The device requires you to blow into a breath sensor before the car will start and logs every attempt. Interlock requirements after refusal range from one year to two years or more depending on the state and prior offenses.4National Conference of State Legislatures. State Ignition Interlock Laws Monthly leasing and maintenance typically runs $100 to $135, paid by you.
The refusal follows you into the criminal case as well. Prosecutors can tell the jury you refused, and some judges treat refusal as an aggravating factor at sentencing if you are convicted of the underlying DUI. Once reinstatement fees, insurance premium increases, and possible fines are added in, the total cost of refusing a chemical test can exceed the penalties for the DUI itself.
Breath Tests and Blood Tests Are Treated Differently
The Supreme Court set a constitutional limit on chemical test penalties in 2016. In Birchfield v. North Dakota, the Court held that a breath test is minimally invasive enough to qualify as a lawful search when you are arrested for DUI, meaning officers do not need a warrant and states may impose criminal penalties for refusing one.5Justia US Supreme Court. Birchfield v. North Dakota, 579 U.S. ___ (2016)
Blood tests are different. Drawing blood pierces the skin and produces a sample that can reveal information beyond blood alcohol content, so the Fourth Amendment requires a warrant before officers can demand it. States cannot criminally punish you for refusing a warrantless blood test, though civil penalties like license suspension can still apply.5Justia US Supreme Court. Birchfield v. North Dakota, 579 U.S. ___ (2016)
In practice, if an officer arrests you and asks for a breath test, the penalties for refusing are at their steepest. If they want blood, they generally need a warrant, and in many jurisdictions they simply get one. Telephonic warrants issue quickly, and once one is in hand, refusal may result in a forced draw plus refusal penalties stacked on top.
Challenging an Administrative License Suspension
If your license is suspended for refusing a chemical test, you can contest it. Most states give you a short window, often 10 to 30 days, to request an administrative hearing. You usually receive a temporary driving permit that covers the gap between arrest and hearing.6National Highway Traffic Safety Administration. Administrative License Revocation or Suspension
The hearing is narrow. The only questions on the table are usually whether the officer had probable cause for the arrest and whether you actually refused the test. It is not a trial on the DUI itself. Missing the deadline almost always means the suspension takes effect automatically, with no second chance to contest it. That is where people trip up most often. The arrest is chaotic, paperwork gets set aside, and by the time the criminal case comes into focus, the administrative deadline has already passed.