In a typical Tennessee DUI stop, roadside field sobriety tests are not the same thing as the chemical breath or blood testing governed by Tennessee's implied-consent law. The standardized roadside exercises—such as the walk-and-turn and one-leg stand—are investigative tools officers use to develop evidence of impairment. A driver can decline to perform voluntary roadside field sobriety exercises, although refusing does not prevent an arrest if the officer already has probable cause based on other evidence.
This distinction matters because people often hear “you consented to testing by driving in Tennessee” and assume that statement applies identically to every roadside exercise. Tennessee's implied-consent statute addresses chemical testing. Field sobriety exercises are a different category of evidence.
Nashville Criminal Defense Lawyer & Former Prosecutor Kevin Kennedy. 615-205-7311. Call or text for a free consultation.
What Are Field Sobriety Tests?
Field sobriety tests are roadside exercises used to help an officer evaluate possible impairment. The National Highway Traffic Safety Administration's standardized battery consists of the horizontal gaze nystagmus test, walk-and-turn test, and one-leg stand test.
Officers may also ask a driver to perform nonstandard exercises. The evidentiary significance of those exercises can differ, and the defense should identify exactly what was requested and how it was administered.
Is It Illegal to Refuse Field Sobriety Tests?
A refusal to perform ordinary roadside field sobriety exercises is not the same statutory implied-consent violation as refusing a covered breath or blood test. Tennessee's implied-consent provisions focus on chemical testing used to determine alcohol or drug content.
That does not mean refusal has no practical effect. The officer can consider the entire encounter and may decide there is probable cause to arrest based on driving, odor, speech, eyes, admissions, balance, behavior, or other observations.
Will Refusing Field Sobriety Tests Keep Me From Being Arrested?
No. Police do not need a failed field sobriety test in every DUI arrest. If other facts establish probable cause, the officer can arrest without the driver completing the exercises.
Refusal therefore removes one potential category of performance evidence, but it does not end the DUI investigation.
Can the Prosecutor Tell the Court I Refused?
The admissibility and significance of a refusal can depend on the circumstances and the purpose for which the State offers it. Body-camera footage can show the request, the driver's response, and whether the driver actually refused or was unable to perform an exercise.
A defense lawyer should review the exact interaction rather than relying on a report that simply says “refused SFSTs.”
What If I Have a Medical Condition or Injury?
Physical limitations can significantly affect balance and coordination exercises. Knee, ankle, back, neurological, vestibular, vision, age-related, or other issues may make a roadside exercise difficult even when the person is sober.
Tell the officer about a legitimate limitation rather than inventing one. If the case is prosecuted, medical records or other evidence may help explain performance.
Are Field Sobriety Tests Accurate?
Standardized field sobriety tests were developed as investigative tools, but they are not a direct measurement of blood-alcohol concentration and do not independently establish guilt. Their value depends in part on proper instructions, administration, conditions, and interpretation.
Road surface, lighting, weather, footwear, traffic, anxiety, language barriers, injuries, and the officer's adherence to training can all be relevant when the performance is evaluated.
What Is the Horizontal Gaze Nystagmus Test?
Horizontal gaze nystagmus, commonly called HGN, involves observing the eyes as they track a stimulus. Officers are trained to look for specified clues associated with impairment.
HGN differs from the walk-and-turn and one-leg stand because it is based on eye movement rather than balance. The officer's training, administration, and testimony can be important to admissibility and weight.
What Is the Walk-and-Turn Test?
The walk-and-turn is a divided-attention exercise in which the person is asked to stand in a particular position, take heel-to-toe steps along a line, turn as instructed, and return.
Video can be particularly useful because a judge or jury may be able to see the actual performance rather than relying only on the officer's written characterization.
What Is the One-Leg Stand Test?
The one-leg stand requires the person to raise one foot and maintain the position while following instructions. Officers look for specified behaviors during the exercise.
Balance problems, injuries, footwear, surface conditions, and deviations from standardized instructions can affect the usefulness of the result.
What Is the Difference Between Field Sobriety Tests and a Breathalyzer?
Field sobriety exercises evaluate observable performance. A breath test attempts to measure alcohol concentration. Tennessee's implied-consent law and refusal consequences concern covered chemical tests, not simply every roadside exercise an officer requests.
A handheld preliminary breath device used during an investigation can also raise different issues from an evidentiary breath test. The exact device and purpose matter.
Should I Explain Why I Am Refusing?
A driver should remain calm and should not physically interfere with the investigation. If declining a voluntary roadside exercise, a clear and respectful response is less likely to create confusion than arguing with the officer.
Do not lie about drinking, medical conditions, or other facts. Statements themselves can become evidence.
Frequently Asked Questions
Do I have to do the walk-and-turn in Tennessee?
Ordinary roadside field sobriety exercises are distinct from the chemical testing governed by Tennessee's implied-consent law. Refusing an exercise does not guarantee that you will avoid arrest.
Will my license be suspended just because I refused field sobriety tests?
The statutory implied-consent license consequences concern covered chemical testing. A roadside field-test refusal is a different issue.
Can police arrest me without field sobriety tests?
Yes. An officer can arrest if the totality of the other evidence establishes probable cause.
What if the officer says I failed but the video looks good?
Body-camera footage can be important evidence. The defense can compare the actual performance with the officer's report and testimony.
Are field sobriety tests the same as a breath test?
No. Field sobriety tests are performance-based investigative exercises; breath testing is chemical testing and is governed by separate legal rules.
Talk With a Nashville DUI Defense Lawyer
Field sobriety evidence should be reviewed on video whenever possible. The questions include whether the exercises were voluntary, whether instructions were standardized, whether the conditions were appropriate, and whether the officer's written conclusions match what the recording actually shows.
Kevin Kennedy Law Firm represents people charged with DUI in Nashville and Middle Tennessee. If field sobriety testing played a role in your arrest, the testing should be analyzed as one part of the State's overall proof—not treated as an automatic finding of impairment.