Why Field Sobriety Tests Are Often Misleading
July 30, 2026
Being asked to perform field sobriety tests during a traffic stop can leave you feeling anxious. Many people assume these tests provide clear proof of impairment, but that isn't how they work. A variety of physical, medical, and environmental factors can affect performance, making the results less reliable than many people believe.
Working with a DUI lawyer is often an important step after an arrest involving field sobriety testing.
At Letsen Law Firm, I help people facing DUI charges by carefully reviewing every aspect of the traffic stop and the evidence presented. With offices in Abingdon and Tazewell, Virginia, I serve clients in Bristol, Smyth County, and Russell County. Contact my office today to schedule a consultation and learn how I can help you prepare a strong defense.
How Field Sobriety Tests Work
Field sobriety tests are physical and mental exercises that law enforcement officers use during DUI investigations. Their purpose is to look for signs of impairment before deciding whether additional testing or an arrest is appropriate. The National Highway Traffic Safety Administration recognizes three standardized field sobriety tests:
Horizontal gaze nystagmus: This test measures involuntary eye movement while a person follows an object from side to side. Officers look for specific indicators that could suggest impairment.
Walk-and-turn: Law enforcement may instruct you to take several heel-to-toe steps in a straight line, turn, and return the same way while following detailed instructions. This is to evaluate your balance, coordination, and ability to follow directions.
One-leg stand: You may be instructed to stand on one foot while counting aloud for a designated period. Officers will observe balance, swaying, hopping, and foot placement.
Although these tests follow standardized procedures, their accuracy depends on proper administration and your physical condition. An experienced Virginia DUI lawyer can help evaluate whether the testing was conducted in accordance with established guidelines.
Factors That Can Affect Test Performance
Poor performance on a field sobriety test doesn't automatically mean you were impaired by alcohol or drugs. Numerous unrelated factors can influence how well you might complete these exercises. Some common factors that could influence your test performance include:
Medical conditions: Inner ear disorders, neurological conditions, back injuries, arthritis, and chronic pain can affect your balance and coordination.
Age: Older adults often have naturally reduced balance or flexibility, which can affect physical testing.
Weather conditions: Rain, wind, snow, or icy pavement could make standing or walking difficult.
Road surfaces: Uneven shoulders, gravel, sloped pavement, or poor lighting can create additional obstacles.
Footwear: High heels, work boots, sandals, or shoes with poor traction can interfere with your balance.
Fatigue: Long work hours, lack of sleep, or exhaustion can reduce your concentration and physical coordination.
Anxiety: Being stopped by police often creates nervousness that affects memory, balance, and the ability to follow multiple instructions.
Because so many external factors can influence the results, field sobriety tests should never be viewed in isolation. Instead, they're only one piece of evidence that you and your lawyer should carefully review when building a defense.
Common Problems You Might Face During a DUI Investigation
Field sobriety testing is only one part of a DUI investigation. The events leading up to the tests often become just as important when evaluating whether the evidence supports criminal charges. Several issues that frequently arise during DUI cases include the following.
Improper Instructions
The standardized tests require officers to provide very specific instructions before the exercises begin. Confusing explanations or skipped steps can affect how someone performs. If the instructions weren't given correctly, the reliability of the results may be called into question or deemed inadmissible in court.
Testing Conditions
Officers are expected to select reasonably safe locations to conduct field sobriety tests. Testing someone on loose gravel, steep inclines, uneven pavement, or poorly lit areas can interfere with the results. Photographs, dash camera footage, and body camera video often help document these conditions.
Officer Observations
An officer's written report will typically include observations about your appearance, speech, balance, and driving behavior. Those observations should remain consistent with the available video evidence. However, when the reports conflict with recordings, that inconsistency can be used to establish your defense.
How to Build a Strong Defense in Virginia
In Virginia, prosecutors must prove every required element of a DUI charge using reliable evidence. Field sobriety tests alone don't automatically establish impairment. To build a defense, you and your attorney should review the following:
The reason for the traffic stop: Officers must have a lawful basis for initiating the stop and conducting a field sobriety test.
The administration of field sobriety tests: Officers must follow established procedures when administering tests.
Body camera and dash camera footage: Video footage can help confirm or contradict an officer's written report.
Chemical testing procedures: Breath or blood testing procedures must comply with Virginia's legal requirements.
Medical history: Any pre-existing conditions can be used to explain poor balance or coordination issues that are unrelated to alcohol or drugs.
Witness statements: Passengers or other witnesses sometimes provide important context regarding driving behavior and physical condition.
Virginia follows strict deadlines for criminal cases, and evidence should be reviewed as early as possible after an arrest. A skilled Virginia criminal defense lawyer can help you preserve surveillance footage, obtain police reports, and identify issues before important evidence becomes unavailable.
Contact My Firm to Speak With a Virginia DUI Lawyer Today
Field sobriety tests don't always tell the whole story, but they can be used as essential evidence when building a DUI defense. At Letsen Law Firm, I help my clients evaluate every part of their DUI case and identify weaknesses in the prosecution's evidence. With offices in Abingdon and Tazewell, Virginia, I serve clients in Bristol, Smyth County, and Russell County. Contact me to schedule a consultation today. I can review your case, answer your questions, and help you take the next step with confidence.