Field Sobriety Tests Are Not What You Think
When an officer pulls you over in Kentucky on suspicion of DUI, one of the first things you’ll be asked to do is perform “field sobriety tests” on the roadside. Most drivers don’t realize that these tests are voluntary in Kentucky and that the officer is designing them to generate evidence against you, not to determine whether you’re safe to drive. Whether you were stopped in Louisville, Lexington, or any Kentucky jurisdiction, Clark + Harris knows how to challenge field sobriety test results.
The Three Standardized Field Sobriety Tests
The National Highway Traffic Safety Administration (NHTSA) has validated only three Standardized Field Sobriety Tests (SFSTs) for DUI detection: the Horizontal Gaze Nystagmus (HGN) test, the Walk and Turn test, and the One Leg Stand test. These are the tests Kentucky officers use most commonly, and the NHTSA manual provides detailed protocols for administering and scoring each one. Any deviation from those protocols calls the results into question.
Horizontal Gaze Nystagmus (HGN)
The HGN test involves the officer moving a stimulus (usually a pen or finger) in front of your eyes and watching for involuntary eye jerking. The test is based on the theory that alcohol exaggerates nystagmus at certain angles. The problem is that many things other than alcohol can cause nystagmus, including medications, medical conditions such as inner ear disorders, head injuries, neurological conditions, and even extreme fatigue. Additionally, officers must administer the test with the stimulus at the correct distance, at the correct height, and at the correct speed — any deviation invalidates the test under NHTSA standards.
Walk and Turn
The Walk and Turn test asks you to walk heel-to-toe along a straight line, turn in a specific manner, and walk back. Officers score eight “clues” that NHTSA claims indicate impairment. But the test is designed to be difficult, especially on uneven roadside surfaces, in poor lighting, in bad weather, or for people with physical limitations. Age, footwear, back injuries, knee problems, weight, and balance disorders all affect performance.
One Leg Stand
The One Leg Stand requires you to stand on one leg while counting out loud for 30 seconds. The officer scores four clues. As with the walk and turn, many physical and environmental factors affect performance. Research shows that even fully sober people fail these tests at significant rates under difficult conditions.
Non-Standardized Tests
Kentucky officers sometimes use non-standardized tests — the ABCs, finger-to-nose, counting backward, the Romberg balance test. These are not NHTSA-validated and have no scientific support for their reliability in detecting alcohol impairment. A skilled defense attorney can attack results from these tests as unreliable and exclude them from evidence in many cases.
Your Right to Refuse Field Sobriety Tests
A critical fact many drivers don’t know: field sobriety tests are voluntary in Kentucky. The implied consent law (KRS 189A.103) applies only to chemical testing (breath, blood, urine), not to roadside physical tests. You can politely refuse to perform field sobriety tests without triggering an automatic license suspension. Many experienced DUI defense attorneys in Louisville and Lexington will tell you that politely declining field tests is almost always the smart move.
Challenging Field Sobriety Test Results in Kentucky DUI Cases
When field sobriety tests have already been performed, the defense strategy shifts to attacking the reliability of the results. Common challenges include:
- Deviation from NHTSA-mandated administration protocols
- Improper scoring or exaggeration of clues by the officer
- Environmental conditions (poor lighting, uneven pavement, weather, traffic)
- Medical conditions that affect performance (injuries, balance disorders, neurological issues)
- Age and physical limitations
- The officer’s training and certification to administer SFSTs
- Video evidence that contradicts the officer’s written description of your performance
Dashcam and body cam video often tells a different story than the officer’s written report. At Clark + Harris, we carefully review every frame of video in every DUI case to identify inconsistencies between what the officer wrote and what actually happened.
Get Experienced Kentucky DUI Defense
Field sobriety test results are not conclusive, and they’re not even particularly reliable. An experienced Kentucky DUI attorney knows how to dismantle them in court. Clark + Harris serves clients throughout Lexington, Louisville, and across the Commonwealth.
Call 859-474-0001 today for a confidential consultation about your Kentucky DUI.
Frequently Asked Questions
How soon should I contact Clark + Harris after being charged in Kentucky?
As soon as possible. Early representation protects your rights during questioning, preserves evidence, and often leads to better outcomes. Call 859-474-0001 — we respond promptly to new inquiries.
Does Clark + Harris represent clients throughout Kentucky?
Yes. We represent clients in all 120 Kentucky counties, both state District and Circuit courts, and federal courts in the Eastern and Western Districts of Kentucky.
What happens during a free consultation with Clark + Harris?
We review the specific charges and evidence, discuss available defenses, explain the likely process in the relevant court, and give you a clear roadmap of next steps — at no cost to you.
Related Resources
If this information applied to your situation, the following Clark + Harris guides may also be helpful:
- Kentucky DUI and CDL: What Truck Drivers Need to Know
- DUI Manslaughter in Kentucky: Vehicular Homicide While Intoxicated
- DUI vs. DWI in Kentucky: Is There a Difference?
- Breathalyzer Defense in Kentucky DUI Cases
- Kentucky DUI Blood Test Challenges