Standardized Field Sobriety Tests: Pass or Fail?

Standardized Field Sobriety Tests were developed as roadside tools for evaluating drivers suspected of alcohol impairment. The word standardized matters.

Each test has a specific protocol, including instructions, demonstrations, stimulus movement, timing, positioning, and defined criteria for identifying clues.

That distinction is important because an officer is not simply observing whether someone “looks sober” while performing a series of balance exercises. The SFST battery is intended to be administered and interpreted according to a standardized methodology.

When that methodology changes, the evidentiary value of the resulting observations may change as well.

A deviation does not necessarily make an entire test meaningless. But the greater the departure from the standardized procedure, the more carefully the resulting conclusions should be evaluated.

The Walk-and-Turn test, sometimes called the nine-step walk-and-turn, is a divided-attention test.

The person is typically instructed to stand in a heel-to-toe position while listening to instructions, then take nine heel-to-toe steps along a line, perform a prescribed turn, and take nine heel-to-toe steps back.

Officers are trained to look for eight standardized clues:

1. 01Cannot maintain balance while listening to instructions
2. 02Starts too soon
3. 03Stops while walking
4. 04Does not touch heel-to-toe
5. 05Steps off the line
6. 06Uses arms for balance
7. 07Performs an improper turn
8. 08Takes the wrong number of steps

Again, this is not truly a pass/fail exercise.

A person could perform most of the test correctly while displaying one or two standardized clues. Conversely, an officer may describe behavior as poor performance even though the behavior observed is not one of the standardized clues.

That distinction can matter.

Conditions Matter

The Walk-and-Turn test also requires physical coordination and the ability to understand and follow a relatively detailed set of instructions.

A thorough DUI case review may therefore consider factors such as:

• Surface conditions
• Lighting
• Footwear
• Weather
• Traffic or roadside distractions
• Age
• Injuries
• Physical limitations
• Whether an actual or imaginary line was used
• Whether the instructions and demonstration were complete
• Whether the officer correctly identified standardized clues

Video evidence can be particularly valuable here because it allows the actual performance to be compared directly with the officer's written description.

A report might say that someone “had difficulty balancing,” for example. The more important question is often: What specifically happened, and was that behavior actually a standardized SFST clue?

One of the most important distinctions in reviewing a DUI investigation is the difference between a standardized clue and a general observation.

An officer may observe that someone:

• Appeared nervous
• Looked down while walking
• Moved slowly
• Asked for instructions to be repeated
• Took time getting into the starting position
• Appeared stiff
• Made movements the officer considered unusual

Those observations may still be documented and considered as part of the overall investigation. But they are not automatically standardized SFST clues.

That matters when police reports use broad descriptions such as “failed field sobriety tests” without explaining exactly what occurred.

The better question is not simply whether the officer thought the person performed poorly.

It is:

What standardized clues were actually observed, how were they obtained, and does the evidence support them?

For years, courts, attorneys, and experts often had little more than an officer's written report describing roadside performance.

Today, body-worn camera and dash-camera video can provide a much more complete picture.

Video may show that an officer's report accurately describes the investigation. It can also reveal discrepancies.

For example:

• A report documents six HGN clues, but the video appears to show only a portion of the standardized examination.
• A report describes significant balance problems, while the subject appears relatively steady on video.
• An officer records a Walk-and-Turn clue for behavior that does not match the standardized definition.
• Instructions on video differ from the procedure described in the report.
• Physical or environmental conditions not mentioned in the report become apparent.

This does not mean video always proves the officer right or wrong. Camera angle, lighting, audio quality, and what falls outside the frame can all create limitations.

But when video exists, a careful DUI review should generally consider the actual recorded evidence alongside the written narrative, rather than relying exclusively on either one.

Usually, that is the wrong question.

A stronger analysis asks:

• Were the Standardized Field Sobriety Tests administered according to the standardized procedure?
• Which validated clues were actually present?
• Were non-standard observations incorrectly treated as clues?
• Were there physical, medical, environmental, or instructional factors that could have affected performance?
• Does the body-worn camera or dash-camera video support the officer's report?
• And, most importantly, how much weight should the SFST results actually receive when considered alongside the rest of the DUI investigation?

SFSTs are only one component of a DUI case. Driving behavior, personal contact observations, statements, chemical testing, toxicology, breath testing, blood testing, video evidence, medical considerations, and the timing of events may all be relevant.

The number of clues written on a police report is therefore often the beginning of the analysis—not the end.