Oklahoma Standardized Field Sobriety Tests (SFSTs) – What Drivers Need to Know

If you were stopped for DUI in Oklahoma, there is a good chance the officer used Standardized Field Sobriety Tests (SFSTs) to decide whether to arrest you. These roadside tests are heavily promoted in police training manuals as “scientifically validated” tools for detecting impaired drivers – but in the real world, they are often misunderstood, misused, and misapplied.

At The Urbanic Law Firm, we study the same NHTSA / IACP SFST Participant Manual that officers use in training. We know what they are supposed to do, what they are allowed to do, and where they routinely go wrong. That knowledge is a powerful weapon in your Oklahoma DUI defense. Attorney Frank Urbanic has completed the same NHTSA SFST training law enforcement officers go through, and he is a qualified SFST instructor. We use this extensive SFST knowledge to pick apart every aspect of your DUI or APC case.

If you were arrested after field sobriety tests in Oklahoma City or anywhere in the state, do not assume the tests were done correctly. An arrest is not a conviction. The SFSTs – and the way they were administered – can be challenged.

What Are Standardized Field Sobriety Tests (SFSTs)?

Standardized Field Sobriety Tests are a set of three specific roadside tests developed and endorsed by the National Highway Traffic Safety Administration (NHTSA) and the International Association of Chiefs of Police (IACP). They are designed to test a driver’s ability to divide attention between mental and physical tasks – skills that are essential for safe driving.

The three NHTSA-approved SFSTs are:

Horizontal Gaze Nystagmus (HGN) – The officer moves a stimulus (usually a pen or small light) side to side while watching your eyes for involuntary jerking.
Walk-and-Turn (WAT) – A “walk the line” test that requires you to take a set number of heel-to-toe steps along a line, turn in a specific way, and return while following instructions.
One-Leg Stand (OLS) – You are asked to stand on one leg while counting in a prescribed manner, without using your arms or putting your foot down.

These are called “standardized” tests because the same instructions, same clues, and same scoring criteria are supposed to be used by officers across the country. According to the training manual, when officers deviate from the standardized procedures, the validity of the tests is compromised.

How Police Are Trained to Detect DUI in Oklahoma

The SFST Participant Manual breaks the DUI detection process into three phases. Understanding these phases helps us analyze what the officer did – and what they should have done – at every step of your stop.

Phase One: Vehicle in Motion

Before the lights ever come on, officers are trained to look for “cues” that a driver may be impaired, such as:

Weaving or drifting within or across lanes
Varying speed for no apparent reason
Driving without headlights at night
Wide or abrupt turns
Nearly striking objects or other vehicles

The manual emphasizes that officers must base their decision to stop on specific, articulable observations. If we find that the stop was made on a hunch rather than on clear cues, we may challenge the legality of the stop and seek to suppress the evidence that followed.

Phase Two: Personal Contact

Once you are stopped, the officer moves into the personal contact phase. This includes:

How you respond when asked for your license, registration, and insurance
How you speak – slurred, slow, confused, or perfectly normal
Odor of alcohol or other substances
Condition of your eyes (red, watery, droopy, normal)
Any admissions to drinking or taking medications

According to the training materials, officers are supposed to observe, ask questions, and look for specific “clues” of impairment during this phase. They are not supposed to jump to conclusions based only on odor or a single sign. We routinely compare the officer’s report, video, and the SFST manual to expose inconsistencies or exaggerations.

Phase Three: Pre-Arrest Screening (Field Sobriety Tests)

If the officer believes further investigation is warranted, they move into the pre-arrest screening phase. This is where the SFSTs are administered, and sometimes a preliminary breath test (PBT) is offered or requested, depending on agency policy.

The SFST manual instructs officers to:

Use the standardized instructions and demonstration for each test
Administer the tests on a reasonably level, dry surface when possible
Observe specific, validated clues on each test
Consider medical issues and other conditions that might affect performance

When officers cut corners – rushing instructions, skipping demonstrations, changing the test, or ignoring obvious physical limitations – they violate the very training they are supposed to follow. That can undermine probable cause for your arrest and the reliability of any later blood or breath test.

The “Science” Behind SFSTs – and Their Limits

The SFST Participant Manual spends considerable time on the physiology of alcohol and the impact of alcohol on the central nervous system. Officers are taught that alcohol:

Is a central nervous system depressant
Is absorbed through the stomach and small intestine into the blood
Is distributed through the body based on water content, with high concentrations reaching the brain
Impair both mental and physical abilities – the exact skills required for safe driving

SFSTs are designed as “divided attention” tests. That means they force a driver to perform physical tasks while following mental instructions – similar to driving, which requires you to process information, make decisions, and coordinate movements at the same time.

However, the manual itself acknowledges important limitations:

SFSTs rely on human observation and judgment; officers must correctly recognize and score specific clues.
Accuracy depends on strict adherence to standardized procedures.
Many factors unrelated to alcohol – such as fatigue, nervousness, injuries, medications, and age – can affect performance.

In other words, SFSTs are not magic. They are tools with known limitations, and in a courtroom, those limitations can matter a great deal.

Common Problems and Errors With SFSTs in Real DUI Stops

In theory, officers administer SFSTs exactly as written in the manual. In practice, we often see:

Improper Instructions and Demonstrations

Failing to demonstrate the Walk-and-Turn or One-Leg Stand as required
Giving confusing or contradictory instructions
Rushing through the explanation and not confirming understanding

The manual emphasizes clear instructions and proper demonstrations. When officers short-cut this process, drivers may “fail” because they were confused, not impaired.

Non-Standard Conditions

Uneven, sloped, or gravel surfaces
Poor lighting, high wind, rain, or cold conditions
Traffic distractions, flashing lights, and loud noise

The SFSTs were validated under controlled conditions. When they are performed on a roadside shoulder at night, in extreme weather conditions, their reliability is reduced – but reports often gloss over these details.

Medical, Physical, and Age-Related Issues

Back, knee, ankle, or foot problems
Inner ear or balance disorders
Advanced age or obesity
Certain medications that affect balance or eye movement

Officers are trained to consider whether a subject is able to perform these tests safely and fairly. Failure to ask about or document medical and physical conditions is a red flag we look for in your case.

Improper Clue Scoring and “Failing” the Test

Each SFST has specific, defined clues. For example, in Walk-and-Turn, officers look for things like stepping off the line, using arms for balance, or taking the wrong number of steps. In One-Leg Stand, they look for swaying, hopping, or putting the foot down.

Common errors include:

Counting actions as “clues” that are not actually part of the standardized scoring system
Penalizing minor or one-time balance checks
Calling the test a “failure” when the number or type of clues does not support that conclusion under NHTSA guidelines

We carefully compare the officer’s testimony and bodycam video to the SFST manual to expose these errors.

How The Urbanic Law Firm Uses the SFST Manual to Fight Your DUI

Because we rely on the same official SFST curriculum that law enforcement uses, we are able to identify and explain where your investigation deviated from NHTSA standards. This can play a critical role at every stage of your case:

Challenging the traffic stop – Did the officer really have reasonable suspicion based on recognized DUI “cues”?
Attacking probable cause for arrest – Were SFSTs administered and scored in a way that truly supports an arrest?
Cross-examining the officer – Does the officer’s testimony match what the NHTSA manual says should have happened?
Suppression motions – If the stop or arrest was unlawful, key evidence may be excluded.
Plea negotiations and trial strategy – Demonstrating weak SFST evidence can change the outcome of the case.

We do not accept “the officer said you failed” as the final word. We test that claim against the very standards the officer was trained to follow.

Frequently Asked Questions About SFSTs in Oklahoma

Are field sobriety tests required in Oklahoma?

SFSTs are generally voluntary. However, many drivers don’t realize that during a stressful roadside stop. Whether you performed the tests or refused them, an experienced Oklahoma DUI attorney can help you understand how that decision affects your case and what defenses may still be available.

How accurate are Standardized Field Sobriety Tests?

According to NHTSA-sponsored studies, the three SFSTs can be reasonably accurate under controlled conditions when properly administered and scored. In the real world, results can be distorted by poor instructions, unsafe conditions, medical issues, and officer bias. SFSTs are not proof of guilt by themselves – they are simply pieces of evidence that can be challenged.

Can nervousness or fatigue cause me to “fail” the tests?

Yes. Nervousness, fatigue, physical discomfort, and ordinary anxiety can all affect performance, especially on balance-based tests like Walk-and-Turn and One-Leg Stand. The officer’s training materials acknowledge that SFSTs measure more than just alcohol – they measure how you perform under stress and divided attention.

What if the officer did not follow the SFST manual?

Deviations from standardized procedures can undermine the reliability of the tests and the officer’s conclusions. When appropriate, we highlight those deviations to the prosecutor and the court, and may use them to attack probable cause, challenge the admissibility of evidence, or cast doubt on the officer’s credibility at trial.

Can SFST errors help my DUI case even if my BAC was over the limit?

Yes. SFST problems can still matter even in so-called “per se” cases involving an alleged BAC of 0.08 or higher. If the stop or arrest was not legally justified, evidence from breath or blood testing may be suppressed. Even when suppression is not granted, weak SFST evidence can influence negotiations and trial strategy.

Arrested After Field Sobriety Tests in Oklahoma? Call The Urbanic Law Firm.

If you or a loved one were arrested for DUI in Oklahoma after taking (or refusing) SFSTs, you need a defense team that truly understands how these tests are supposed to be administered and how they are actually used on the roadside.

The Urbanic Law Firm uses the official SFST training materials to scrutinize every step of your stop, your tests, and your arrest for errors and weaknesses that can be used in your defense.

Contact us today to schedule a consultation and learn how we can help.

You don’t have to face a DUI charge alone. Put a law firm on your side that knows what the SFST manual really says – and how to use it for your benefit.

This page is for informational purposes only and is not legal advice. Every case is unique; consult an attorney about your specific situation. Page last updated November 15, 2025. Consult the statutes listed above for the most up-to-date law.