If you’ve been pulled over for suspected DUI in Missouri, there’s a good chance an officer asked you to perform field sobriety tests. These might include walking heel-to-toe in a straight line, standing on one leg, or following a pen with your eyes.
While these tests are commonly used, they are not nearly as reliable as many people assume. In fact, field sobriety tests are one of the most misunderstood parts of a DUI investigation.
Why Field Sobriety Tests Are Problematic
Field sobriety tests are designed to help officers decide whether to make an arrest but they are far from scientific or foolproof. Many factors unrelated to alcohol can affect how someone performs, including:
Nerves and anxiety – Being stopped by police is stressful, even for sober drivers.
Medical or physical conditions – Inner ear issues, joint problems, past injuries, or neurological conditions can affect balance and coordination.
Weather and road conditions – Uneven pavement, poor lighting, rain, wind, or gravel can all impact performance.
Officer judgment – These tests rely heavily on the officer’s interpretation, which can be subjective and prone to error.
Failing a field sobriety test does not automatically mean someone was intoxicated. It simply means the officer believed there was enough reason to proceed with an arrest.
At B Block Law LLC, we regularly explain this distinction to clients because it controls which legal filing applies and what happens next.
Driving Behavior and Physical Condition in a DUI Case
A DUI case doesn’t start with sobriety tests, it starts with the traffic stop itself.
Why Were You Pulled Over?
Police must have a lawful reason to initiate a stop. Common reasons include:
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Drifting between lanes
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Speeding or driving unusually slow
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Sudden braking
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Rolling through stop signs or signals
If the officer lacked reasonable suspicion, that issue can become a key part of the defense.
What Officers Look For During the Stop
After pulling someone over, officers often focus on behavior, such as:
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Difficulty locating a license or insurance
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Trouble following instructions
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Speech patterns or perceived confusion
These observations are often subjective. Fatigue, stress, medical issues, or simple nervousness can look like impairment, even when alcohol is not involved.
Are Field Sobriety Tests Fair for Everyone?
Field sobriety tests are not designed for all body types, ages, or physical conditions.
For example:
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Older individuals may struggle with balance-based tests
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People with joint pain or mobility issues may have difficulty with agility tasks
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Someone who is naturally uncoordinated or anxious may perform poorly despite being sober
A larger, older, or less athletic person is far more likely to “fail” these tests than a younger, more agile individual. Officers do not always account for these differences, which can lead to unfair arrests.
How B Block Law LLC Approaches DUI Defense
At B Block Law LLC, we do not simply accept an officer’s conclusions at face value. Every DUI case requires careful review.
Our approach often includes:
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Examining whether the traffic stop was lawful
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Reviewing dash cam and body cam footage
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Evaluating how field sobriety tests were administered
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Identifying medical or physical factors that affected performance
Details matter in DUI cases, and small errors can have a major impact.
Take the Next Step
A DUI charge can affect your license, finances, and future but it should not be decided by a flawed test or assumption.
If you’ve been arrested for DUI in St. Louis or Chesterfield, getting clear information early matters.
B Block Law LLC
St. Louis & Chesterfield, Missouri
314-325-HELP (4357)
https://stlcriminaldefenselawyers.com/
This article pairs with an informational video explaining how field sobriety tests work and why they are often challenged in Missouri DUI cases.
Disclaimer: The choice of an attorney is important and should not be solely based upon advertisements. Each DWI case is different and you should consult with an attorney on specific legal issues.
Brendan Block
Attorney at Law
Brendan practices law in St. Louis, Missouri and surrounding areas. He handles all criminal cases, but especially DWI, shoplifting, theft and possession cases. He is a former prosecutor who now defends his clients with the utmost care and attention.
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