If you are stopped on suspicion of DUI in Lexington, Louisville, or anywhere in Kentucky, the officer will likely ask you to perform field sobriety tests. These tests are designed to help establish probable cause for a DUI arrest — but they are also rife with subjectivity, administrative errors, and situational factors that can produce false positives. Clark + Harris defends Kentucky DUI cases with a particular focus on challenging improperly administered field sobriety tests.

The Three Standardized Field Sobriety Tests

The National Highway Traffic Safety Administration (NHTSA) has validated three standardized field sobriety tests (SFSTs) that Kentucky officers are trained to administer:

Horizontal Gaze Nystagmus (HGN)

HGN involves the officer moving a stimulus (usually a pen or finger) across the driver’s field of vision while observing the eyes for involuntary jerking movements. The officer looks for six clues across both eyes. Four or more clues are considered an indication of impairment. HGN is supposedly the most accurate of the three tests, but it requires proper administration — specifically, appropriate angle, speed, and distance. Officers often administer HGN incorrectly, and medical conditions such as natural nystagmus, certain medications, and head injuries can all produce false positives.

Walk and Turn

In this test, the driver is instructed to walk nine heel-to-toe steps along a straight line, turn as directed, and return in the same manner. The officer looks for eight clues: balance during instructions, starting too soon, stopping, missing heel-to-toe contact, stepping off the line, raising arms for balance, improper turn, and wrong number of steps. Two or more clues are considered an indication of impairment.

One-Leg Stand

The driver is asked to stand on one leg for 30 seconds while counting aloud. The officer looks for four clues: swaying, raising arms, hopping, and putting the foot down. Two or more clues indicate impairment.

Non-Standardized Tests

Officers sometimes administer non-standardized tests such as the alphabet recitation, finger-to-nose, or counting backward. These tests are not validated by NHTSA and their results carry less weight in court.

Problems with Field Sobriety Tests

At Clark + Harris, we have challenged field sobriety test results in courts across Kentucky — from Fayette District Court in Lexington to Jefferson District Court in Louisville to rural courthouses statewide. Common issues include:

Physical and Medical Conditions

Many drivers fail field sobriety tests because of conditions unrelated to alcohol: age, weight, injury, inner ear problems, back or leg pain, diabetes, and fatigue. Drivers over 65 or who are more than 50 pounds overweight were excluded from NHTSA’s validation studies, meaning the tests are not reliably calibrated for them.

Environmental Factors

Tests should be administered on a hard, dry, level surface with adequate lighting. Tests on the roadside often fail to meet these conditions — uneven pavement, gravel shoulders, passing traffic, poor lighting, or bad weather can all affect performance.

Footwear and Clothing

High heels, boots, and certain clothing can affect the walk-and-turn and one-leg stand tests. Officers rarely account for these variables in their reports.

Improper Administration

Officers must give specific instructions and demonstrations. Deviations from the NHTSA protocol can invalidate the results. We scrutinize dashcam and body camera footage to identify these deviations.

Your Right to Refuse Field Sobriety Tests

Unlike Kentucky’s implied consent law for chemical testing, there is no statutory requirement to perform field sobriety tests. You can decline without automatic license consequences. However, officers may use the refusal as one factor in establishing probable cause for arrest. Decisions about whether to perform or decline tests should be made carefully, and discussing the circumstances with an experienced DUI attorney is essential.

How Clark + Harris Challenges FSTs

We build our challenge around three pillars:

Video review: We watch every frame of dashcam and body camera footage, looking for deviations from protocol and environmental issues.
Officer training: We obtain the officer’s DUI training records to identify gaps or outdated certifications.
Expert testimony: In complex cases, we retain DUI defense experts to testify about test reliability and administration.

Call Clark + Harris

If you were arrested for DUI after failing field sobriety tests, call Clark + Harris at 859-474-0001. Our attorneys defend DUI cases throughout Kentucky, from Lexington to Louisville and beyond, and we know how to challenge improperly administered field sobriety tests.

Related Resources

If this information applied to your situation, the following Clark + Harris guides may also be helpful:

DUI Field Sobriety Tests in Kentucky: What to Know