Was Your Field Sobriety Test Administered Correctly in Olmsted County?
Use this SFST Error Checker to see if Your Tests Were Administered Correctly in Rochester, MN.
If you were asked to do the eye test, walk a line, or stand on one leg before being arrested for DWI in Rochester, Minnesota, those tests are valid only if the officer followed a very specific national protocol.
Most people assume the officer did everything right. Most are wrong.
NHTSA, the National Highway Traffic Safety Administration, publishes a standardized manual that dictates exactly how each field sobriety test must be administered, including the exact speed of eye-test movements, the specific questions that must be asked before testing, the required surface conditions, the timing of the one-leg stand, and what must happen before a portable breath test (PBT). When any of these steps is skipped, done incorrectly, or done out of order, NHTSA’s manual states that “the validity may be compromised.”
This tool walks you through what happened during your stop and flags every potential deviation, with citations to the actual NHTSA training manual used by officers in Minnesota. It covers the eye test (Horizontal Gaze Nystagmus), the Walk and Turn, the One-Leg Stand, the roadside PBT, and the conditions under which they occurred.
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Was Your Field Sobriety Test Done Correctly?
Field sobriety tests are only valid when administered exactly as required by NHTSA's national protocol. Even one deviation can compromise the validity of the entire test. Answer the questions below and find out if the officer followed the rules — with citations to the actual NHTSA training manual.
Procedural errors in field sobriety testing can lead to suppression of evidence — or full dismissal.
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What NHTSA's Protocol Actually Requires — And Why It Matters
The Standardized Field Sobriety Tests, better known as SFSTs, were developed by NHTSA in the 1970s and have been periodically updated, most recently in 2023. They are called “standardized” for one specific reason: they are only scientifically validated when administered in a precise, consistent way.
This is not a technicality. It is the scientific foundation on which the tests rest.
The three tests, HGN, Walk and Turn, and One-Leg Stand, were validated against specific accuracy rates when administered correctly: HGN at 88%, Walk and Turn at 79%, and One-Leg Stand at 83%. Those accuracy numbers only hold when the protocol is followed exactly. When it isn’t, those percentages mean nothing — because the test being administered is no longer the one studied.
The Eye Test (HGN)
The Horizontal Gaze Nystagmus test requires the officer to ask about your eye health and general medical conditions before starting. You must remove your glasses. The stimulus must be positioned 12 to 15 inches from your nose, slightly above eye level. The movement must be smooth and continuous, never jerky or interrupted mid-pass. Your head must be upright and in line with your spine to prevent Positional Alcohol Nystagmus, a known false positive that NHTSA explicitly warns about. If any of these steps are out of sequence, performed incorrectly, or skipped entirely, the results may reflect the officer's technique rather than your condition.
9 Step Walk and Turn (WAT)
The Walk and Turn test requires a full demonstration, not just verbal instructions. The officer must physically show you the heel-to-toe stance, demonstrate at least three steps, and demonstrate the turn. You must be in the heel-to-toe stance during the instruction phase, and you are already being scored the moment you assume that stance. The surface must be "reasonably dry, hard, level, and non-slippery." If you were wearing unusual footwear, you must have been offered the chance to take it off. Two or more scored clues indicate a probable BAC of 0.08 or higher. However, if the test was improperly administered, every clue the officer recorded is potentially invalid.
The One-Leg Stand (OLS)
The One-Leg Stand must be timed for exactly 30 seconds and stopped at that point. Allowing it to run longer creates fatigue, which the test was never designed to measure. The officer must demonstrate the stance fully. You must be asked about physical conditions that could affect balance. Two or more clues indicate probable BAC at or above 0.08.
The Portable Breath Test (PBT)
A PBT administered at the roadside is only reliable if the officer observed you for at least 15 minutes before administering it. This observation period exists to rule out residual mouth alcohol from burping, regurgitating, or having substances in your mouth, all of which can artificially inflate a PBT result. Minnesota case law and the standard breath-testing protocol both recognize this requirement. A PBT taken immediately after a traffic stop, without a proper observation period, can produce a reading that does not reflect your actual blood alcohol content.
Three Things Most People Don't Know About Field Sobriety Tests
You do not need to do them.
Roadside field sobriety tests in Minnesota are not mandatory. Unlike the evidentiary breath or blood test administered after arrest, which carries implied consent consequences for refusal, roadside SFSTs are voluntary.
Officers are not required to inform you of this, and most don't. Officers want to have a DWI suspect on video "failing" tests that most criminal defense lawyers are not experienced in challenging.
The eye test is not about whether your eyes move.
HGN nystagmus, the involuntary jerking of the eyes, is present in virtually everyone at sufficiently high BAC. But it is also present in people with inner ear conditions, those taking certain medications, those who are fatigued, and those with neurological conditions. More importantly, it can be present when the test is administered incorrectly. The presence of nystagmus only means what the officer says it means if the test was administered correctly.
The Drug Recognition Expert is a separate layer.
If you were arrested for a drug-related DWI or a high-BAC situation, a Drug Recognition Expert (DRE) may have been called in. DREs follow a separate 12-step evaluation protocol and maintain a Rolling Log of every evaluation they've conducted, including their accuracy rate over their career. Under Minnesota DWI practice, your attorney should always request the Rolling Log. It can reveal a DRE who has been accurate only 60-70% of the time in similar cases, a powerful cross-examination tool.
Knowing these three things before you make any decisions about your case can change everything. If an officer didn't follow protocol, that doesn't automatically mean your case gets dismissed — but it gives your attorney real grounds to file motions, challenge evidence, and negotiate from a position of strength rather than weakness.
Frequently Asked Questions About Field Sobriety Tests in Minnesota
Can a DWI case be dismissed because of SFST errors in Minnesota?
Yes, it can, though the outcome depends on the nature and severity of the errors and the specific facts of your case. At the omnibus (pretrial) hearing, your attorney can file a motion to suppress the field sobriety test results for protocol violations. If the motion succeeds, the state may lose its key evidence of impairment. In cases where the FST results were the primary basis for probable cause to arrest, suppression can lead to dismissal of the entire charge. Even when full dismissal doesn't occur, suppressed test evidence dramatically weakens the state's case and creates strong grounds for reducing the charge.
Are field sobriety tests required in Minnesota?
No. Roadside standardized field sobriety tests (SFSTs) are voluntary in Minnesota. The implied consent law, which creates consequences for refusal, applies only to the evidentiary chemical test (breath, blood, or urine) administered after you are arrested. It does not apply to roadside FSTs. You can decline to participate in field sobriety testing without the automatic license revocation that follows refusal of the evidentiary test. Most people don't know this because officers are not required to inform them.
What is the 15-minute observation rule for the PBT in Minnesota?
Before administering any breath test, including the roadside PBT, standard protocol requires the officer to observe the subject for at least 15 consecutive minutes. During that period, the officer must confirm that the subject has not burped, belched, regurgitated, or placed anything in their mouth. These events introduce mouth alcohol, which can artificially inflate the breath reading. A breath test administered without a proper observation period yields a result that does not reliably reflect actual blood alcohol content. Although the PBT is generally inadmissible at trial, a compromised PBT reading may be invalid as a basis for probable cause to arrest.
How accurate is the HGN eye test for detecting impairment?
According to NHTSA's research, when administered correctly under standardized conditions, the HGN test is approximately 88% accurate in indicating a BAC of 0.08 or higher. However, that accuracy rate applies only when every step of the standardized protocol is followed precisely. When the officer deviates from protocol, such as incorrect positioning, improper stimulus speed, or failure to check for medical conditions, the test no longer has a validated accuracy rate because it is no longer the one studied. Additionally, HGN can result from causes entirely unrelated to alcohol, including certain medications, inner ear disorders, and fatigue.
What happens if the officer skipped the demonstration during my Walk and Turn test?
Under NHTSA protocol, a full physical demonstration is required for both the Walk and Turn and the One-Leg Stand. The officer must demonstrate the heel-to-toe stance, steps, and the turn, not merely describe them. A purely verbal instruction does not satisfy the standardized protocol. If the officer failed to demonstrate, any clues observed during the test may be unreliable because you were not given the standardized conditions under which the test was validated. This is a specific argument your attorney can raise at the omnibus hearing.
What does it mean if the officer didn't ask about my health before the eye test?
NHTSA explicitly requires officers to "ask questions about the subject's eyes and general health conditions prior to administering the HGN test." This step is not optional. The purpose is to rule out medical causes of nystagmus, such as inner ear disorders, certain medications, neurological conditions, and head injuries, that can produce eye movements that look identical to alcohol-induced nystagmus. If the officer skips this step and you have any eye or health condition, the HGN results may have a medical explanation that was never investigated.
Can I use the SFST error checker results to help my attorney?
Absolutely. Print or screenshot your results and bring them to your first consultation. They give your attorney a structured starting point for reviewing the dashcam footage, the police report, and the field sobriety test scoring sheet. Many attorneys request the officer's SFST proficiency log and, if a DRE was involved, the DRE's Rolling Log, both of which can reveal the officer's experience level and accuracy history. The more specific information you provide about what happened during your stop, the more effectively your attorney can identify defensible issues.
If the surface was uneven or the lighting was poor, does that affect my case?
Yes, meaningfully. NHTSA requires testing on a "reasonably dry, hard, level, non-slippery surface." If testing occurred on grass, gravel, a sloped shoulder, or a wet surface, the officer was not testing on a validated surface condition. Similarly, poor lighting affects both the officer's ability to observe clues and your ability to perform the tests safely. While courts weigh these arguments differently, they are recognized reliability factors that experienced DWI defense attorneys raise regularly in Olmsted County.
Use These Links For Additional Help.
- DWI Deadline Tracker — Live countdown to every critical deadline after your arrest
- License Revocation Calculator — How long will your license be revoked?
- DWI Charge Calculator — What degree of DWI are you facing?
- Free DWI Guide Book — Tom Hagen’s complete Minnesota DWI survival guide. Free.