You can refuse to take a field sobriety test in every state. These roadside physical exercises — the walk-and-turn, one-leg stand, and eye-tracking test — are voluntary across the United States, and no state imposes a direct legal penalty for declining them. The complication comes later in the stop, with the chemical breath or blood test after arrest, which is governed by a completely different set of rules. Knowing where that line sits is what keeps a refusal from backfiring.
Why the Roadside Tests Are Voluntary
Field sobriety tests exist to help an officer build probable cause for a DUI arrest. They are investigative tools, not legal requirements. No state statute compels you to walk a straight line, stand on one leg, or follow a penlight with your eyes during a traffic stop. An officer may ask, and the request can sound like an instruction, but you can politely decline.
The reason these tests stay voluntary is the timing. They happen before an arrest, while the officer is still deciding whether a crime occurred. You have no obligation at that stage to help build the case against you. That posture changes entirely once you’re arrested and the officer requests a chemical test, which is a separate matter covered further down.
What the Officer Is Asking You to Do
The National Highway Traffic Safety Administration has validated three standardized field sobriety tests that officers around the country are trained to administer. The Horizontal Gaze Nystagmus test checks for involuntary jerking of your eyes as they track a moving object. The Walk-and-Turn requires nine heel-to-toe steps along a line, a turn, and nine steps back. The One-Leg Stand asks you to balance on one foot for roughly 30 seconds while counting aloud.1National Highway Traffic Safety Administration (NHTSA). DWI Detection and Standardized Field Sobriety Test (SFST) Participant Manual The Walk-and-Turn and One-Leg Stand are designed as divided-attention tasks that split your focus between physical balance and a mental exercise like counting.
NHTSA research found that when all three standardized tests are administered together and correctly, officers identified drivers above 0.08 BAC in 91% of cases.2National Highway Traffic Safety Administration (NHTSA). Evaluation of the Effects of SFST Training on Impaired Driving Detection Read the other direction, that means about 1 in 10 sober drivers can be flagged as impaired. Nervousness, fatigue, uneven pavement, medical conditions affecting balance, age, and footwear can all produce clues of impairment that have nothing to do with alcohol.
Officers sometimes use non-standardized tests as well, things NHTSA has never validated. Reciting the alphabet, counting backward, touching a finger to your nose, or the Romberg balance test where you close your eyes and estimate the passage of time. These have no established accuracy rates and are even more open to challenge in court than the standardized battery.
What Happens if You Decline
Refusing a field sobriety test does not end the encounter. The officer can still arrest you based on everything else observed: the odor of alcohol, slurred speech, bloodshot eyes, erratic driving, or open containers visible in the vehicle. Your refusal simply means the officer has one fewer piece of evidence.
In many jurisdictions, a prosecutor can tell the jury you refused and argue the refusal shows consciousness of guilt. A defense attorney can push back by pointing to your legal right to decline, physical limitations that would make the tests unreliable, or the subjective nature of a roadside evaluation. Whether the argument gains traction varies by case and by state, but expect a prosecutor to try using it.
Strategically, many DUI defense attorneys view a refusal as a net positive for most drivers. A failed field sobriety test captured on dashcam gives prosecutors concrete, visual evidence to show a jury. A refusal gives them only an argument about your state of mind, which is easier to rebut.
The Roadside Breath Device Is Not the Station Test
Between the field sobriety tests and the formal chemical test at the station sits a device that trips up a lot of drivers: the preliminary breath test, or PBT. This is the small handheld unit an officer may produce at the roadside, before any arrest. It looks like a breathalyzer, and officers may refer to it casually, which leads people to believe it’s the mandatory chemical test.
In most states the PBT is treated like a field sobriety test. It’s a pre-arrest investigative tool, you can decline it, and refusal does not trigger implied consent penalties. Many states don’t even allow PBT readings as evidence at trial. Some states do require certain categories of drivers, typically those under 21 or on DUI probation, to submit to a PBT, and refusal in those cases can carry its own consequences. If you fall into one of those categories, check your state’s specific rule.
The core distinction: the roadside PBT is not the same as the evidentiary breath test given at the police station after arrest. Confusing the two is one of the most common mistakes drivers make during a DUI stop.
The Post-Arrest Chemical Test Is a Different Story
Once you have been arrested for DUI, the legal picture shifts. Every state has an implied consent law providing that by driving on public roads, you have already agreed to submit to a chemical test of breath, blood, or urine if lawfully arrested for impaired driving. Refusing the chemical test after arrest triggers penalties that are entirely separate from the DUI charge itself.
The purpose of chemical testing is to measure your blood alcohol concentration. In 49 states the legal limit is 0.08%. Utah lowered its limit to 0.05% in 2018.3National Highway Traffic Safety Administration. Lower BAC Limits Breath testing is the most common method at the station after arrest. Blood tests are more common when drug impairment is suspected or when the driver is unconscious or unable to provide a breath sample.
Before requesting the test, officers in most states must read an implied consent warning explaining that refusal will result in license suspension and potentially other penalties.
Penalties for Refusing the Chemical Test
The most immediate and universal penalty is an automatic license suspension imposed by the state motor vehicle department. It happens regardless of whether you’re ever convicted of DUI. You can be acquitted at trial and still serve the full suspension for refusing the test.
For a first-time refusal, most states impose a suspension of six months to one year. Second-offense suspensions commonly reach two years, and third offenses can mean three years or longer. Refusal suspensions often run longer than the suspension you would face for failing the test, a deliberate policy choice meant to discourage refusal.
Beyond the suspension, depending on the state you may also face:
- Criminal charges. Several states treat chemical test refusal as a separate misdemeanor.
- Administrative fines, typically around $125 to $500 for a first offense.
- Ignition interlock requirements. States including Kansas, West Virginia, Wisconsin, and Iowa mandate an interlock device following a refusal. In Arkansas, a refusal makes you ineligible for an interlock-restricted permit at all, leaving no legal way to drive during the suspension.4National Conference of State Legislatures. State Ignition Interlock Laws
- Evidence at trial. Your refusal can be presented to the jury as evidence of guilt, similar to a field sobriety test refusal.
There is also a practical shift worth knowing about. Many jurisdictions now use electronic warrant systems, and an officer can request a warrant for a blood draw from a judge electronically from the patrol car. In many places the warrant comes back approved in 15 to 20 minutes, and some departments report turnaround under 10 minutes.5Responsibility.org. A Guide to Implementing Electronic Warrants Once a warrant issues, your consent is no longer needed and blood is drawn. You then face both the DUI charge based on the BAC result and the administrative penalties for the refusal itself.
A Special Warning for CDL Holders
If you hold a commercial driver’s license, the stakes for refusing a chemical test are dramatically higher, and this applies even if you were driving your personal car at the time of the stop. Federal regulations require a one-year disqualification from operating any commercial motor vehicle for a first refusal, and three years if you were hauling hazardous materials. A second refusal in a separate incident results in a lifetime disqualification from commercial driving.6eCFR. 49 CFR 383.51 – Disqualification of Drivers That’s the mandatory federal floor, not a maximum. For anyone whose livelihood depends on a CDL, a chemical test refusal can end a career.
The Short Version
Field sobriety tests at the roadside are voluntary in every state and you can decline them without a direct legal penalty, though an officer can still arrest you on other evidence and a prosecutor may bring your refusal up at trial. The preliminary breath test at the roadside falls into the same voluntary category in most states. What is not voluntary, and what carries automatic license suspension and other penalties everywhere, is the chemical breath or blood test after a lawful DUI arrest. Keeping those two moments straight is the whole game.