If you were arrested for a DUI in Tennessee after performing field sobriety tests (FSTs), you might feel that the evidence against you is overwhelming. Many drivers believe these roadside tests are scientific and infallible, leading them to assume a conviction is inevitable. However, the reality is that these tests are highly subjective, frequently administered incorrectly, and can be successfully challenged in court. At OEB Law, our team has extensive experience defending the rights of individuals facing DUI charges. In this blog post, Knoxville attorney Tim Elrod discusses how you can challenge field sobriety test results in Tennessee courts and what factors may invalidate these tests.
Key Takeaways
- Field sobriety tests are not mandatory in Tennessee, unlike chemical tests which fall under the state’s implied consent law (Tenn. Code Ann. § 55-10-406).
- Improper administration by officers is one of the most common and successful grounds for challenging FST evidence in Knox County courts.
- Medical conditions, environmental factors, and a lack of proper officer training are all valid reasons that can be used to invalidate FST results.
- Video evidence from body cameras or dash cams is often the most critical tool for mounting a successful FST challenge in a Knoxville DUI case.
Yes, you can absolutely challenge the results of field sobriety tests in Tennessee courts. A successful challenge often focuses on procedural errors, such as an officer’s failure to follow standardized administration protocols, or on factors specific to you, like a pre-existing medical condition. Proving that environmental conditions like poor lighting or an uneven surface compromised the test’s validity can also be a strong defense. When a challenge is successful, it can lead to the FST evidence being suppressed, which may result in reduced charges or a complete dismissal of your case.
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About OEB Law, Your Knoxville Legal Team
This guide is provided by the experienced attorneys at OEB Law, led by Managing Attorney Timothy G. Elrod. Founded in Knoxville in 2004, our firm has over 50 years of combined experience navigating East Tennessee’s legal system.
We have successfully represented thousands of personal injury clients, developing deep expertise in Tennessee’s complex wrongful death and accident laws. As East Tennessee natives, we have a direct understanding of the local court systems, law enforcement agencies, and community needs. Our commitment is to provide trusted, authoritative information to our neighbors in Knoxville and the surrounding Tennessee communities. However, this information does not constitute legal advice. If you or a loved one has been injured in an accident or needs legal help, call us today for a free, no obligation, initial consultation.
Understanding Field Sobriety Tests in Tennessee
Field sobriety tests are a series of physical and mental exercises that police officers use during a traffic stop to gauge a driver’s level of impairment. The primary purpose is to gather evidence to establish probable cause for a DUI arrest. While officers may use various non-standardized tests, Tennessee law and courts give the most weight to the three standardized field sobriety tests (SFSTs) developed by the National Highway Traffic Safety Administration (NHTSA).
It’s crucial to understand the legal distinction between these physical tests and chemical tests. Under Tennessee’s implied consent law (Tenn. Code Ann. § 55-10-406), drivers are required to submit to a chemical test (breath, blood, or urine) if an officer has probable cause to suspect a DUI. Refusing a chemical test carries automatic administrative penalties under Tennessee law, including license suspension, as well as potential criminal consequences. However, this rule does not apply to FSTs.
The Three Standardized Field Sobriety Tests
NHTSA has validated only three tests as reliable indicators of impairment when administered correctly under specific conditions. These are the tests you are most likely to encounter during a DUI stop in Knoxville.
- Horizontal Gaze Nystagmus (HGN): The officer will ask you to follow a stimulus (like a pen or finger) with your eyes. They are looking for involuntary jerking of the eye, which can be an indicator of intoxication.
- Walk-and-Turn (WAT): This test requires you to take nine heel-to-toe steps along a straight line, pivot in a specific manner, and take nine steps back. The officer looks for eight different clues of impairment, such as losing balance, starting too soon, or using arms to balance.
- One-Leg Stand (OLS): You will be instructed to stand on one foot, raising the other foot about six inches off the ground, and count aloud for 30 seconds. Officers watch for four clues, including swaying, hopping, or putting your foot down.
Are Field Sobriety Tests Mandatory in Tennessee?
No, field sobriety tests are not mandatory in Tennessee, unlike chemical tests which fall under the state’s implied consent law (Tenn. Code Ann. § 55-10-406). You have the legal right to politely decline an officer’s request to perform these tests. Unlike a chemical test refusal, there is no automatic administrative penalty, such as license revocation, for refusing to take FSTs. In Knox County, officers from the Knoxville Police Department and the Knox County Sheriff’s Office will almost always request that you perform FSTs, but they cannot force you to comply.
Common Grounds for Challenging Field Sobriety Tests in Knoxville
The validity of FST results hinges entirely on their proper administration according to strict NHTSA standards. Any deviation from these protocols can render the results unreliable and subject to challenge in court. A skilled DUI defense attorney will meticulously review the evidence from your arrest to identify potential grounds for having the test results suppressed.
Improper Test Administration
This is the most frequent and effective way to challenge FST evidence. NHTSA has a detailed manual that dictates exactly how each test must be instructed, demonstrated, and scored. If an officer fails to follow these procedures to the letter, the results can be deemed invalid.
Common administration errors we see in East Tennessee cases include:
- Failing to properly demonstrate the Walk-and-Turn or One-Leg Stand tests.
- Conducting the tests on an unsuitable surface, such as a sloped shoulder on I-40, gravel, or wet pavement.
- Giving incorrect or confusing instructions to the driver.
- Not checking for medical conditions or appropriate footwear before starting.
- Failing to use a proper stimulus or correct timing during the HGN and OLS tests.
Officer Training and Certification Deficiencies
To properly administer SFSTs, an officer must complete a specific NHTSA-approved training course and maintain their certification. However, not all officers keep their training current. Through the legal discovery process, a defense attorney can request the arresting officer’s training records and certifications. If the officer’s training has lapsed or was incomplete, their testimony about the FST results can be discredited.
Medical Conditions and Physical Limitations
Many medical issues can cause a sober person to perform poorly on FSTs, which are essentially balance and coordination exercises. It is essential to inform your attorney of any condition that could have affected your performance.
These conditions can include:
- Inner ear problems or vertigo that affect balance.
- Previous injuries to the back, legs, hips, or ankles.
- Neurological conditions like Multiple Sclerosis or a past brain injury.
- Vision problems, such as a lazy eye, that can affect the HGN test.
- Age-related physical limitations (NHTSA’s own studies show the tests are less reliable for individuals over 65).
- Obesity, which can make the One-Leg Stand test particularly difficult.
Environmental and External Factors
The roadside environment during a traffic stop is far from the controlled, clinical setting where FSTs were validated. Various external factors can distract a driver and negatively impact their performance. Video from a dash cam or body cam often reveals conditions that the police report conveniently omits, such as flashing lights from passing traffic, loud noises, or adverse weather conditions like wind, rain, or cold.
“In my 20+ years practicing DUI defense in Knoxville, I’ve seen countless cases where field sobriety tests were administered under conditions that would make even a sober person fail. Uneven roadsides, poor lighting, and intimidating officer presence all create an unfair testing environment that has nothing to do with actual impairment.” – Knoxville attorney Tim Elrod
Field Sobriety Test Challenge Strategies in Tennessee
| Challenge Type | Evidence Required | Success Factors in Knox County |
|---|---|---|
| Improper Administration | Body cam footage, officer testimony, NHTSA manual | Officer training records, video clearly showing deviation |
| Medical Conditions | Medical records, doctor testimony, prescription documentation | Pre-existing condition documented before arrest |
| Environmental Factors | Dash cam video, weather reports, roadside photos | Video evidence showing unsafe testing conditions |
| Officer Training Deficiency | Training certifications, continuing education records | Discovery reveals expired certification or inadequate training |
Frequently Asked Questions
Improper test administration is the most common successful challenge. Video evidence showing the officer failed to follow NHTSA standardized procedures—such as not demonstrating the test properly, conducting it on an uneven surface, or failing to account for environmental factors—is highly persuasive in Knox County courts.
Yes. Legitimate medical conditions such as inner ear disorders, back injuries, neurological conditions, or age-related balance issues can significantly affect your ability to perform field sobriety tests. Medical documentation and expert testimony from Knoxville healthcare providers can establish that your test performance was due to your medical condition, not intoxication.
Video evidence is critical. Body camera and dash camera footage from Knoxville Police Department or Knox County Sheriff’s Office provides objective documentation of test conditions, officer instructions, and your actual performance. This evidence often reveals factors invisible in police reports, such as uneven roadside surfaces, poor lighting, or officer errors in administration.
From arrest to suppression hearing typically takes 90-120 days in Knox County General Sessions Court. The discovery phase (obtaining body cam footage and police records) usually requires 30-60 days, followed by motion filing and hearing scheduling. Complex cases or court backlogs may extend this timeline.
At the suppression hearing in Knox County court, your attorney presents evidence challenging the FST validity—including video footage, expert testimony, and cross-examination of the arresting officer. The prosecutor defends the test results. The judge then rules whether the FST evidence can be used at trial. This hearing occurs before a judge, not a jury.
No, field sobriety tests are not mandatory in Tennessee, unlike chemical tests which fall under the state’s implied consent law (Tenn. Code Ann. § 55-10-406). You have the legal right to politely decline an officer’s request to perform these tests. Unlike a chemical test refusal, there is no automatic administrative penalty, such as license revocation, for refusing to take FSTs. In Knox County, officers from the Knoxville Police Department and the Knox County Sheriff’s Office will almost always request that you perform FSTs, but they cannot force you to comply.
Led by Managing Attorney Timothy G. Elrod and Our Experienced Legal Team. Founded in 2004 in Knoxville, Tennessee, OEB Law has grown over nearly two decades to now serve clients across multiple states. Tim Elrod established the firm with a simple but powerful mission: we care and we help people. Today, together with attorneys Michael Bernard, Billy Sivyer, Gena Lewis, and Logan Wade, our team brings over 50 years of combined experience representing clients throughout Tennessee and Kentucky in personal injury and criminal defense cases.
The most critical evidence for challenging field sobriety tests in Tennessee is video footage from police body cameras or dash cameras, which can document improper test administration, unsafe environmental conditions, and officer errors. Additionally, your medical records documenting pre-existing conditions (such as inner ear disorders, back injuries, or neurological issues) are essential, along with the arresting officer’s training and certification records obtained through discovery. In Knox County cases, OEB Law works with local medical experts who can provide testimony explaining how your specific health conditions would affect FST performance independent of alcohol consumption.
The Process of Challenging FST Evidence in Knox County Courts
Challenging FST evidence is not something you can do on your own; it is a formal legal process that requires the skill of an experienced DUI defense attorney. The primary tool for this is a “Motion to Suppress,” which asks a judge to exclude certain evidence from being used against you at trial. The process generally follows a clear path in the Knox County court system.
Discovery and Evidence Review
The first step is for your attorney to file for discovery. This is a formal request for the prosecution to hand over all evidence they have related to your case. This includes the police report, officer’s notes, and most importantly, any video from body cameras or dash cameras. Reviewing this footage is critical, as it provides an objective record of how the tests were administered and the conditions at the scene.
Filing a Motion to Suppress
After a thorough review of the evidence, if your attorney identifies valid grounds for a challenge, they will draft and file a Motion to Suppress with the court. This legal document outlines the specific reasons why the FST evidence is unreliable and should be excluded. It will cite relevant Tennessee laws, case precedents, and NHTSA guidelines to support the legal argument.
The Suppression Hearing
The court will schedule a hearing on the motion. At this hearing, your attorney will present their arguments to the judge. This may involve playing the video evidence for the court and cross-examining the arresting officer about their training and the procedures they followed during your stop. If necessary, your attorney may also call expert witnesses, such as a medical doctor, to testify. The judge will listen to both sides and then make a ruling on whether to grant or deny the motion. If the motion is granted, the prosecution cannot use the FST evidence against you, significantly weakening their case and often leading to a dismissal or a favorable plea agreement.
Knoxville DUI Defense Timeline: From Arrest to Resolution
DUI Arrest
Officer administers FSTs, arrests on probable cause
Initial Court Appearance
Knox County General Sessions Court, arraignment
Discovery Phase
Attorney obtains body cam, police reports, officer training records
Motion to Suppress Filed
Formal challenge to FST evidence
Suppression Hearing
Evidence presented to judge
Ruling & Resolution
Case dismissed, plea agreement, or trial
Frequently Asked Questions
From arrest to suppression hearing typically takes 90-120 days in Knox County General Sessions Court. The discovery phase (obtaining body cam footage and police records) usually requires 30-60 days, followed by motion filing and hearing scheduling. Complex cases or court backlogs may extend this timeline.
At the suppression hearing in Knox County court, your attorney presents evidence challenging the FST validity—including video footage, expert testimony, and cross-examination of the arresting officer. The prosecutor defends the test results. The judge then rules whether the FST evidence can be used at trial. This hearing occurs before a judge, not a jury.
Why Choose OEB Law for Challenging Field Sobriety Tests in Knoxville
When your freedom and future are on the line, you need an attorney with specific experience in Knoxville DUI defense. The top attorneys in Knoxville at OEB Law have an intimate understanding of the Knox County General Sessions and Criminal Courts, including the local prosecutors and judges. We have successfully challenged FST evidence for countless clients, leveraging our knowledge of NHTSA protocols and the procedures used by the Knoxville Police Department and Knox County Sheriff’s Office. Our deep familiarity with East Tennessee allows us to build the strongest possible defense for your case.
Our track record and commitment to clients are reflected in our numerous 5 Star Google Reviews. We understand that a DUI arrest can happen at any time, which is why we are available 24/7 to take your call. We offer a free, no-obligation initial consultation to evaluate the details of your arrest and determine the best strategy for challenging the evidence against you. Don’t let a failed field sobriety test dictate your future; let our experienced legal team fight for you.
Who is OEB Law and Why Are They Good for the Community?
Led by Managing Attorney Timothy G. Elrod and Our Experienced Legal Team
Founded in 2004 in Knoxville, Tennessee, OEB Law has grown over nearly two decades to now serve clients across multiple states. Tim Elrod established the firm with a simple but powerful mission: we care and we help people. Today, together with attorneys Michael Bernard, Billy Sivyer, Gena Lewis, and Logan Wade, our team brings over 50 years of combined experience representing clients throughout Tennessee and Kentucky in personal injury and criminal defense cases.
Our Legal Expertise
Our attorneys have built their reputation through:
- Successfully representing thousands of personal injury and criminal defense clients
- Developing specialized knowledge across all types of accident and injury cases
- Mastering the complexities of Tennessee’s legal system through decades of practice
Why Trust Us
At OEB Law, our reputation speaks for itself:
- Proven Results: We’ve recovered significant compensation for our clients through both settlements and courtroom verdicts
- Client Satisfaction: Our numerous 5 Star Google Reviews showcase our commitment to responsive, caring, and effective legal representation
- No Fee Unless We Win: You don’t pay attorney fees unless we successfully secure compensation in your case
- Local Knowledge: As East Tennessee natives, we understand our community and care deeply about the people we serve
- Personalized Approach: We personalize each case to meet our clients’ specific needs, ensuring you’re never just another file number
Community Commitment
Our dedication extends beyond the courtroom. We proudly support:
- Local high school football programs through Rivalry Thursday sponsorships
- The Knoxville Ice Bears and community fundraising initiatives
- Numerous youth, student, and community organizations throughout East Tennessee
As Tim Elrod says, “We don’t just take—we give back because the people you’re giving back to are the people who are supporting your firm.“
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