Field sobriety tests in Utah are roadside exercises officers use to gather evidence of impairment. While many drivers believe they must comply, Utah law does not require you to perform field sobriety tests. Understanding each test, its limitations, and your right to refuse can be critical to your DUI defense strategy.
Updated: July 2026
Key Takeaways
- The three NHTSA-standardized field sobriety tests are HGN, Walk-and-Turn, and One-Leg Stand.
- Non-standardized tests like the alphabet recitation and finger count have no validated scientific basis.
- Field sobriety tests are voluntary in Utah. Implied consent does not apply to roadside exercises.
- Many medical conditions, environmental factors, and physical limitations can cause false positives.
- Refusing field sobriety tests cannot be used as evidence of guilt in Utah court.
Field sobriety tests are one of the most common tools Utah law enforcement officers use to build DUI cases. But they are also one of the most scientifically questionable. From a defense perspective, field sobriety tests offer fertile ground for cross-examination and suppression motions. This article explains what each test involves, why the results may be unreliable, and what you need to know about your right to refuse.
What Are the Three Standardized Field Sobriety Tests Used in Utah?
The National Highway Traffic Safety Administration (NHTSA) has validated three standardized field sobriety tests through research conducted in the 1970s and 1980s. These are the only tests that carry any recognized scientific basis when administered according to NHTSA guidelines.
Horizontal Gaze Nystagmus (HGN). The officer asks you to follow a stimulus, typically a pen or flashlight, with your eyes while keeping your head still. The officer looks for three clues in each eye: lack of smooth pursuit, distinct nystagmus at maximum deviation, and onset of nystagmus before 45 degrees. The HGN test is the most scientifically valid of the three standardized tests, but it can produce false positives due to medical conditions, certain medications, and even fatigue.
Walk-and-Turn. You are instructed to take nine heel-to-toe steps along a straight line, turn in a specific manner, and take nine steps back. The officer looks for eight possible clues including losing balance, starting too soon, stepping off the line, and using arms for balance. The Walk-and-Turn test is particularly susceptible to environmental factors such as uneven pavement, poor lighting, or inclement weather.
One-Leg Stand. You are instructed to stand with one foot approximately six inches off the ground while counting aloud until the officer tells you to stop. The officer looks for four clues including swaying, using arms for balance, hopping, or putting your foot down. The test is timed at 30 seconds, which is significantly longer than most people realize and can challenge even completely sober individuals.
What Are Non-Standardized Field Sobriety Tests in Utah?
In addition to the three NHTSA-standardized tests, Utah officers frequently administer non-standardized tests that have no validated scientific basis. These include the alphabet test (reciting the alphabet from a specific letter to another), the finger-to-nose test, the finger count test, and the modified Romberg balance test.
The NHTSA has never validated these non-standardized tests for determining impairment. Their reliability depends entirely on the officer’s subjective observation, and they are easily challenged in court. Defense attorneys frequently file motions in limine to exclude evidence from non-standardized tests on the grounds that they lack scientific foundation.
Non-standardized tests are particularly vulnerable to challenge because there are no standardized scoring criteria, no validation studies supporting their use, and no accepted administrative procedures. An officer essentially creates the test on the side of the road and determines the results based on personal judgment.
The NHTSA’s own research shows that the standardized field sobriety tests, when administered exactly according to protocol, have accuracy rates of approximately 77% for HGN, 68% for Walk-and-Turn, and 65% for One-Leg Stand. When administered outside protocol, accuracy drops significantly.
NHTSA Standardized Field Sobriety Testing Guidelines
Can You Refuse Field Sobriety Tests in Utah?
Yes, you can refuse field sobriety tests in Utah, and the refusal cannot be used as evidence of guilt. This is a critical point that distinguishes field sobriety tests from chemical tests under Utah’s implied consent law.
Utah’s implied consent law applies only to chemical tests of blood, breath, or urine. When you drive on Utah roads, you are deemed to have consented to a chemical test if an officer has probable cause to believe you were driving under the influence. Refusing a chemical test results in an automatic 18-month license suspension for a first refusal.
Field sobriety tests are entirely different. They are physical exercises that require your active participation. The officer cannot compel you to perform them, and Utah courts have held that refusing field sobriety tests is not admissible as evidence of consciousness of guilt.
Most DUI defense attorneys advise clients to politely decline field sobriety tests. The tests are designed to produce evidence against you, and performing poorly provides the officer with probable cause to arrest you and request a chemical test. There is virtually no scenario in which performing the tests helps your case.
What Factors Affect the Accuracy of Field Sobriety Tests?
Multiple factors can cause a sober person to perform poorly on field sobriety tests. These accuracy issues form the basis of many DUI defense challenges in Utah courts.
| Factor | How It Affects Test Performance | Tests Affected |
|---|---|---|
| Medical conditions | Inner ear disorders, vertigo, neurological conditions, and injuries affect balance and coordination. | Walk-and-Turn, One-Leg Stand |
| Medications | Many prescription and over-the-counter medications cause nystagmus as a side effect. | HGN |
| Fatigue | Sleep deprivation causes involuntary eye movements and impairs balance. | All three standardized tests |
| Age | Adults over 65 struggle with balance tests even when unimpaired. NHTSA research shows higher false positive rates in older adults. | Walk-and-Turn, One-Leg Stand |
| Weight | Significant overweight or obesity affects balance and coordination. | Walk-and-Turn, One-Leg Stand |
| Footwear | High heels, loose shoes, or boots with poor traction affect balance test performance. | Walk-and-Turn, One-Leg Stand |
| Weather conditions | Wind, rain, snow, and uneven surfaces make balance tests difficult for sober individuals. | Walk-and-Turn, One-Leg Stand |
| Nervousness | Anxiety caused by the traffic stop itself can cause shaking, difficulty following instructions, and poor performance. | All tests |
How Are Field Sobriety Tests Challenged in Utah DUI Defense?
Utah DUI defense attorneys use several strategies to challenge field sobriety test evidence. The most common approach involves attacking the officer’s administration of the tests. NHTSA guidelines require standardized tests to be administered in a specific manner with precise instructions. If the officer deviated from the protocol, the test results may be inadmissible or given reduced weight.
Another common challenge focuses on the officer’s training. The officer must have completed NHTSA-approved training in standardized field sobriety testing and must demonstrate proficiency in administering the tests. Defense attorneys can request the officer’s training records and certification history to identify gaps or deficiencies.
Environmental conditions at the scene are also fertile ground for challenge. Defense attorneys will examine dashcam or body camera footage to evaluate road surface conditions, lighting, weather, and other factors that may have affected test performance. If the conditions were less than ideal, the reliability of the test results is called into question.
Finally, medical and physical factors specific to the defendant can be presented to explain poor performance. A defense attorney may call a medical expert to testify about how the defendant’s inner ear condition, medication, or physical injury would affect balance and coordination independent of alcohol consumption.
Frequently Asked Questions About Field Sobriety Tests in Utah
Do I have to do field sobriety tests in Utah?
No. Field sobriety tests are voluntary in Utah. You have the legal right to politely decline. Refusing field sobriety tests cannot be used as evidence against you in court.
What is the difference between field sobriety tests and chemical tests in Utah?
Field sobriety tests are physical exercises performed roadside. Chemical tests involve analysis of your blood, breath, or urine for alcohol or drugs. Utah’s implied consent law applies only to chemical tests, not field sobriety tests.
Can I refuse a field sobriety test without losing my license in Utah?
Yes. Refusing field sobriety tests carries no license suspension penalty. Only refusing a chemical test triggers the implied consent suspension (18 months for a first refusal).
How accurate are field sobriety tests?
NHTSA research indicates that the three standardized tests have accuracy rates between 65% and 77% when administered strictly according to protocol. In practice, many officers deviate from protocol, making the tests even less reliable.
What should I say when an officer asks me to do field sobriety tests?
Politely and respectfully decline. You can say something like “Officer, I have been advised by my attorney to respectfully decline field sobriety tests. I am happy to cooperate in other ways.” Do not argue or resist.
Can the officer arrest me for refusing field sobriety tests?
Refusing field sobriety tests alone is not grounds for arrest. However, if the officer has other evidence of impairment such as odor of alcohol, slurred speech, or bloodshot eyes, they may use that evidence to establish probable cause for arrest despite your refusal.
What happens if I fail field sobriety tests but I am not impaired?
Many factors including medical conditions, fatigue, nervousness, and poor road conditions can cause a sober person to perform poorly. Your defense attorney can present evidence of these factors to challenge the test results.
Can field sobriety tests be used against me in court?
Yes, if you performed the tests and the officer documented your performance, the results can be used as evidence of impairment. This is why most defense attorneys advise clients to decline these tests.
Closing Thoughts on Field Sobriety Tests in Utah
Field sobriety tests are a common but deeply flawed tool for determining impairment. Understanding that these tests are voluntary, scientifically limited, and subject to challenge can help you make informed decisions during a traffic stop. If you are arrested after performing field sobriety tests, an experienced DUI defense attorney can scrutinize the officer’s administration of the tests, the environmental conditions, and your individual physical factors to build a strong defense.
If you have been arrested for DUI in Utah, do not assume that poor field sobriety test performance means your case is hopeless. Contact a qualified defense attorney who can evaluate whether the tests were properly administered and whether your results can be challenged.
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This article is for informational purposes only and does not constitute legal advice. Consult with a qualified Utah criminal defense attorney for advice specific to your situation.
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