Field Sobriety Test Challenges in Wisconsin
Pulled over for OWI? The tests don’t always tell the truth. Call or schedule a free consultations with Chirafisi Anderson, S.C. today.
Understanding Field Sobriety Tests (FSTs) in Wisconsin
When Wisconsin law enforcement suspects impaired driving, officers often rely on standardized field sobriety tests (FSTs) developed by the National Highway Traffic Safety Administration (NHTSA). These tests are designed to observe coordination, balance, and divided attention—but they are not scientific tests and do not measure alcohol concentration.
In practice, FSTs are highly subjective. Performance can be affected by factors unrelated to intoxication, including medical conditions, age, anxiety, fatigue, footwear, weather, lighting, and uneven surfaces.
At Chirafisi Anderson, S.C., we regularly challenge field sobriety test evidence in OWI cases throughout Southern and Central Wisconsin, including Dane, Rock, Jefferson, Dodge, Columbia, Sauk, Iowa, and Green Counties. Even minor deviations from standardized procedures or environmental issues can potentially undermine the reliability of these tests.
How Field Sobriety Tests Are Used in Wisconsin Courts
In Wisconsin OWI cases, field sobriety tests are used as observational evidence, not scientific proof of intoxication. Prosecutors rely on FST performance primarily to justify probable cause for arrest, not to establish a specific level of impairment or blood alcohol concentration.
Wisconsin courts consistently recognize that FSTs are inherently subjective. Their evidentiary value depends on whether the officer followed standardized NHTSA procedures, whether the officer was properly trained, and whether testing conditions were accurately documented. Deviations in instructions, environmental conditions, or scoring can significantly reduce—or eliminate—the weight courts give to FST evidence.
Importantly, because FSTs often form the foundation for an OWI arrest, weaknesses in how the tests were administered can affect everything that follows, including the legality of the arrest and the admissibility of chemical test evidence obtained afterward.
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The Three Standardized Field Sobriety Tests in Wisconsin
Law enforcement officers are trained to administer three standardized field sobriety tests developed by the National Highway Traffic Safety Administration (NHTSA). These tests are intended to be conducted under specific conditions and scored using standardized criteria. When those standards are not followed, the reliability of the results is significantly reduced.
Horizontal Gaze Nystagmus (HGN)
The HGN test involves observing involuntary jerking of the eyes as a stimulus moves horizontally across the field of vision. Officers are trained to look for specific indicators that may suggest impairment.
HGN testing is highly sensitive to proper administration. Officers must position the stimulus at the correct distance, move it at a prescribed speed, and ensure the subject’s head remains still. Deviations from these requirements can invalidate the observations. In addition, nystagmus can be caused by factors unrelated to alcohol, including fatigue, medical conditions, prescription medications, or visual stimuli such as flashing emergency lights.
Wisconsin courts limit the use of HGN evidence. It may be considered as observational evidence of impairment, but it cannot be used to establish a specific blood alcohol concentration.
Walk-and-Turn
The walk-and-turn test is a divided-attention exercise requiring the subject to take nine heel-to-toe steps along a straight line, turn using a specific method, and return in the same manner.
This test assumes ideal conditions that rarely exist during roadside stops. Uneven pavement, sloped shoulders, poor lighting, weather conditions, footwear, or unclear instructions can all affect performance. Errors attributed to intoxication may instead reflect nervousness, misunderstanding, or physical limitations.
Proper demonstration and standardized instructions are critical. Interruptions, inconsistent explanations, or deviations from NHTSA protocol reduce the evidentiary value of the test.
One-Leg Stand
The one-leg stand requires the subject to balance on one foot for approximately 30 seconds while counting aloud. Officers observe for specific indicators such as swaying, hopping, or putting the foot down.
Balance-based tests are particularly susceptible to non-alcohol-related factors. Age, weight, injuries, inner-ear conditions, footwear, and surface conditions can all affect performance. Even small timing or instruction errors undermine the standardization required for the test to be considered reliable.
Non-Standardized Field Sobriety Tests
In addition to standardized field sobriety tests, Wisconsin law enforcement officers sometimes ask drivers to perform informal or non-standardized exercises. Common examples include the finger-to-nose test, reciting the alphabet, counting backward, or other coordination tasks.
These exercises are not approved or validated by the National Highway Traffic Safety Administration and do not follow any recognized scientific or standardized protocol. Unlike standardized FSTs, there are no uniform instructions, scoring criteria, or reliability studies supporting their use.
Because non-standardized tests lack objective benchmarks, courts treat them with greater skepticism. Performance on these exercises is highly subjective and can be influenced by stress, misunderstanding, nervousness, fatigue, or physical limitations unrelated to alcohol or drug impairment.
From a defense perspective, non-standardized tests are often challenged in one of two ways:
- Exclusion of the test results due to lack of scientific or evidentiary reliability; or
- Credibility challenges demonstrating that the officer relied on subjective impressions rather than standardized indicators of impairment.
When non-standardized tests play a significant role in an arrest decision, their unreliability can undermine the officer’s justification for probable cause.
Your Right to Refuse Field Sobriety Tests in Wisconsin
Field sobriety tests are voluntary under Wisconsin law. Unlike chemical tests, they are not governed by Wisconsin’s implied consent statute and carry no automatic penalties for refusal.
You may lawfully decline to perform field sobriety tests without committing a separate violation or triggering license revocation. An officer may still make an arrest based on other observations, but refusal alone does not constitute probable cause or an offense.
Because field sobriety tests are often used to justify an arrest, refusing them can limit the amount of subjective evidence available to law enforcement. In many cases, this becomes a critical issue when evaluating whether the officer had sufficient grounds to proceed with an OWI arrest or to request chemical testing later.
That said, refusal decisions should be evaluated in context. Officers may still rely on driving behavior, statements, or other observations. The legal impact of refusal depends on the totality of circumstances and how the stop unfolded.
Challenging Field Sobriety Tests in Wisconsin
Field sobriety tests are not self-proving evidence. To be relied upon in court, the State must establish that the tests were administered properly, under appropriate conditions, and by a trained officer. When those prerequisites are not met, the evidentiary value of the tests drops sharply.
At Chirafisi Anderson, S.C., we challenge field sobriety tests by grounding the analysis in objective proof, not officer conclusions. Our approach commonly includes:
When field sobriety tests are the primary basis for an OWI arrest, demonstrating these failures can materially affect the case, including suppression of evidence obtained after an unlawful arrest.
Field Sobriety Test Lawyers in Wisconsin
Challenging field sobriety test evidence requires attorneys who understand both NHTSA protocols and how Wisconsin judges evaluate FST testimony in real cases. Outcomes often turn on whether the defense can demonstrate protocol failures, environmental factors, or inconsistencies between an officer’s report and video evidence.
At Chirafisi Anderson, S.C. our attorneys routinely litigate field sobriety test issues in OWI cases across Southern and Central Wisconsin, including Dane, Rock, Jefferson, Columbia, Sauk, Iowa, and Green Counties. We are familiar with how local courts handle motions to suppress, probable-cause challenges, and trial testimony based on FSTs.
Field sobriety test evidence is frequently the foundation for an OWI arrest. When that foundation is weak, the State’s case may be significantly limited. Effective representation focuses on identifying those weaknesses early and preserving them for litigation, negotiation, or trial.
Take Action Now
Field sobriety tests are often the foundation for an OWI arrest—but they are not scientific proof of impairment. When these tests are administered improperly or relied upon too heavily, they can be challenged.
If your OWI arrest was based on field sobriety tests, contact Chirafisi Anderson, S.C. for a free consultation. We represent clients throughout Southern and Central Wisconsin, including Dane, Rock, Jefferson, Columbia, Sauk, Iowa, and Green Counties, and focus on identifying weaknesses in FST evidence early—before they shape the rest of the case.