Law Offices of Michael E. Cindrich, APC 225 Broadway, Suite 2100 San Diego, CA 92101

Field Sobriety Tests

A DUI investigation that involves field sobriety testing places an individual at a significant disadvantage from the outset, often long before any chemical test is administered. These roadside exercises are presented as objective measures of impairment, yet they rely heavily on an officer’s observations, the surrounding conditions, and the driver’s physical and emotional state. Misinterpretation is common, and the consequences of an arrest based on such testing can be immediate and far-reaching.

San Diego Field Sobriety Test Lawyer

A person confronted with this situation must act quickly, as the legal and procedural steps that follow can shape the course of the entire case. The Law Offices of Michael E. Cindrich, APC provides informed guidance on these issues, explaining key terms, the steps involved in cases where field sobriety tests play a central role, and how a San Diego field sobriety test lawyer protects clients throughout the process. The Law Offices of Michael E. Cindrich serve clients throughout San Diego County, including Chula Vista, Oceanside, Escondido, Carlsbad, El Cajon, Vista, San Marcos, Encinitas, National City, La Mesa, and the city of San Diego.

For a free, confidential consultation, call (619) 262-2500.

Overview of Field Sobriety Tests in San Diego

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How Field Sobriety Tests Work in a San Diego DUI Stop

Overview of Common SFSTs — During a DUI investigation in San Diego, officers rely on the standardized field sobriety tests recognized by the National Highway Traffic Safety Administration. These assessments are designed to evaluate divided attention, coordination, and balance. The three primary standardized tests include:

  • Horizontal Gaze Nystagmus (HGN) Test — The officer moves a stimulus, such as a pen or small light, back and forth in front of the subject’s eyes to look for specific involuntary jerking movements associated with alcohol consumption. Typical signs include trouble smoothly following movement, clear eye jerking at full sideways look, and eye jerking appearing early, possibly showing impairment when seen together.
  • Walk-and-Turn Test — This divided-attention test requires the subject to listen to detailed instructions, maintain the instructional stance, take nine heel-to-toe steps along a line, execute a precise pivot turn, and take nine steps back. Officers look for missteps, balance issues, starting too soon, or difficulty following instructions, which may indicate impairment.
  • One-Leg Stand Test — The subject must raise one foot approximately six inches off the ground, keep arms at their sides, and count aloud for about 30 seconds. Officers monitor for swaying, hopping, putting the foot down, or losing count, all of which are treated as potential clues of impairment.

Although these tests are widely used, none are mandated by statute. Instead, officers use them as investigative tools to help determine whether probable cause exists to arrest a person for violating Vehicle Code § 23152.

Use of SFSTs During a Traffic Stop — The roadside environment can influence the outcome of these tests. Lighting, weather, surface conditions, footwear, age, injury, and stress can all affect performance, and NHTSA training acknowledges that ideal testing conditions rarely exist in real-world stops. Officers are trained to interpret specific “clues,” but the observations remain subjective. The tests do not directly measure blood alcohol concentration, and they cannot determine whether a person is actually impaired by alcohol, drugs, or any combination. Because the tests serve only as observational tools, their reliability depends on proper administration and accurate interpretation.

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California DUI Laws That Apply to Field Sobriety Tests

How State DUI Statutes Treat Impairment — California Vehicle Code § 23152 sets out the main DUI offenses, including driving under the influence of alcohol, drugs, or a combination of both, and driving with a blood alcohol concentration of 0.08 percent or more. These laws define what the prosecution must prove, but they do not require a person to take field sobriety tests. Officers instead use SFST performance as part of their evaluation when deciding whether a driver appears impaired under the standard in § 23152(a).

How Implied Consent Works After Arrest — Under Vehicle Code § 23612, a driver arrested for a violation of § 23152 must submit to a breath or blood test, depending on availability, to measure alcohol or drug content. This requirement begins only after a lawful arrest. Field sobriety tests fall outside the implied consent statute, meaning a driver is not legally obligated to perform them. Officers may still request them as an investigative step before establishing probable cause, but declining the tests does not violate § 23612.

How BAC Presumptions Affect DUI Cases — Vehicle Code § 23610 explains the presumptions that apply at trial when a chemical test shows specific alcohol levels. Results below 0.05 percent create a presumption of no impairment, results between 0.05 and 0.08 percent carry no presumption either way, and results at or above 0.08 percent create a presumption of impairment. These presumptions apply to chemical tests only, not to field sobriety tests, though prosecutors often attempt to use SFST performance to support their impairment theory.

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Problems With Field Sobriety Tests During a DUI Arrest

Limitations in Real-World Testing Conditions — San Diego roadside conditions rarely match controlled testing environments. Uneven pavement, poor lighting, traffic, cold weather, and wet surfaces can affect balance and concentration, causing sober drivers to appear impaired. Officers do not always document these factors.

Scientific Concerns About Accuracy — Studies show SFSTs can misidentify sober individuals as impaired, especially in drug-related cases. A 2023 National Library of Medicine study found that 49.2% of placebo participants were still labeled impaired by trained officers, highlighting that SFSTs often fail to distinguish THC impairment from normal behavior.

Issues Related to Officer Interpretation — SFST observations are subjective. Nervousness, fatigue, age, footwear, injuries, or medical conditions can influence performance.

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How Police Must Administer Field Sobriety Tests in San Diego

Requirements for Proper Instructions — Officers must explain each test clearly and demonstrate what the driver is expected to do. NHTSA guidelines emphasize that standardized wording helps ensure consistent evaluation. When an officer modifies instructions or fails to demonstrate them correctly, the test’s accuracy is compromised. Courts may consider these deviations when determining whether the results are reliable.

Expectations for Standardized Procedures — Tests like the Walk-and-Turn and One-Leg Stand must follow specific sequencing and conditions. Even small procedural errors—improper timing, incorrect positioning, failure to account for hazards—can alter results. Bodycam review often reveals these issues.

Consequences of Nonstandard Administration — When officers fail to follow training protocols, courts may give SFST results less weight or exclude them under Evidence Code § 352. Improperly administered tests are, therefore, vulnerable to challenge in San Diego DUI cases.

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Why Drivers Often Struggle With Field Sobriety Tests Even When Sober

Effects of Stress and Anxiety — A DUI stop is a stressful event, and many people struggle to perform tasks that require balance and coordination when under pressure. Elevated heart rate, adrenaline, and fear of arrest can interfere with divided-attention tasks. These natural reactions have nothing to do with alcohol or drug use but can still be mistaken for impairment.

Influence of Physical and Medical Conditions — Back injuries, knee problems, vertigo, neurological issues, and simple age-related balance challenges can all affect performance. NHTSA acknowledges that the tests do not fit all physical profiles. Officers may overlook these conditions or fail to inquire about them, which can result in misleading clues being recorded.

Difficulty of the Tasks Themselves — The tests require precise movements and timing, and even healthy individuals may not perform them flawlessly. Small missteps can be marked as clues, and several clues may be interpreted as impairment. The scientific research described above shows that sober individuals often accumulate enough clues to be labeled impaired, which highlights the need for careful legal review.

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How a Field Sobriety Test Lawyer Challenges the Officer’s Observations

Use of Legal Standards to Test Credibility — Evidence Code §§ 801–802 govern expert opinions and their foundation. Even when officers are not formally classified as experts, these rules apply if they offer interpretations of SFST performance. A lawyer can challenge whether the officer had a proper basis for the conclusions stated in reports or testimony.

Review of Video and Reports for Inconsistencies — Bodycam footage often reveals details missing from the written narrative. A lawyer compares the video with the officer’s statements to identify inconsistencies, exaggerations, or omissions that may undermine the prosecution’s claims.

Application of Evidence Code § 352 — Courts may exclude SFST evidence if it risks undue prejudice or confusion. A lawyer may argue that improperly administered or unreliable tests should be excluded, particularly given the high false-positive rates documented in sober individuals.

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How FST Evidence Connects to Chemical Tests and Refusals in California

Relationship Between SFSTs and Probable Cause — In San Diego DUI stops, officers use field sobriety test performance to decide whether they have probable cause to arrest under Vehicle Code § 23152. These tests inform the arrest decision but do not create any legal obligation to participate. The arrest itself determines whether the implied-consent rules of § 23612 apply.

Limits on Refusing Chemical Tests — A driver may lawfully decline field sobriety tests without violating implied-consent laws. The mandatory breath or blood test requirement begins only after arrest. Once arrested, refusing a chemical test can trigger DMV consequences under § 23612, but declining SFSTs carries no such penalties.

Impact on the Officer’s Evaluation — Although refusing SFSTs is legal, officers may interpret it as evasive. A San Diego DUI lawyer can explain that a lawful refusal cannot be treated as evidence of guilt, especially when the law imposes no duty to perform these tests.

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How Field Sobriety Tests Affect a DUI Case in San Diego Courts

Use of SFST Results by Prosecutors — In San Diego, prosecutors often use SFST performance to argue impairment under Vehicle Code § 23152(a), pointing to swaying, missed steps, or difficulty following instructions. A defense lawyer must challenge these claims using science, training standards, and the specific conditions of the stop.

Interaction With BAC Presumptions — When BAC results fall within § 23610 ranges, prosecutors may rely on SFSTs to bolster their case—especially in borderline BAC situations. This interplay requires careful analysis because SFSTs are not always reliable indicators of impairment.

Judicial Evaluation of Reliability — Judges consider whether the officer properly administered the tests, whether conditions were appropriate, and whether the driver had medical or physical issues affecting performance. If the tests appear unreliable, courts may give them little weight or exclude them under Evidence Code § 352.

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Common Defenses

Challenges to the Basis for the Traffic Stop — A DUI case may be dismissed if the initial stop lacked reasonable suspicion. A lawyer reviews claims such as weaving or speeding to determine whether the stop was lawful. If unconstitutional, evidence gathered afterward may be suppressed.

Attacks on Improper Administration of Tests — Counsel reviews whether the officer followed NHTSA standards and whether the testing environment was suitable. Deviations or unclear footage can make the results unreliable.

Presentation of Alternative Explanations — Medical conditions, fatigue, age, footwear, and stress can affect performance. A lawyer may present records or testimony showing that these factors, not impairment, explain the observations, weakening the prosecution’s interpretation.

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What a San Diego Field Sobriety Test Lawyer Does

Role of a DUI Defense Lawyer — A San Diego DUI lawyer focusing on field sobriety test issues guides a client from arrest through court hearings and DMV actions. Counsel reviews how the stop occurred, whether the officer had lawful grounds under Vehicle Code § 23152, and whether statements or observations were obtained properly. Because field sobriety tests often justify arrest and later chemical testing under § 23612, a lawyer examines police reports, bodycam footage, and witness accounts to find errors that may weaken the prosecution’s case.

Purpose of Legal Representation — A defense lawyer protects a client’s rights when the consequences of a DUI arrest can escalate quickly. Officers may misinterpret normal movements as impairment, and those subjective impressions can appear as “facts” in reports. Counsel challenges unsupported interpretations, prevents harmful assumptions from shaping the case, and preserves evidence and witness information early on.

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Why Someone Facing a DUI Should Call a San Diego Field Sobriety Test Lawyer Immediately

Need for Fast Action After an Arrest — California deadlines for DMV license-suspension challenges are strict, and a lawyer ensures the request is filed on time and all defenses are preserved.

Importance of Preserving Evidence — Bodycam and dashcam video, dispatch logs, and calibration records can be lost if not requested promptly. Early involvement helps secure this evidence.

Benefits of Skilled Legal Representation — DUI penalties affect employment, driving privileges, and long-term opportunities. A lawyer experienced in field sobriety issues can identify weaknesses in the case and pursue strategies that protect the client’s rights.

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Frequently Asked Questions

What is a field sobriety test and why do police use it?
Police use field sobriety tests to check coordination and attention during DUI stops, but real-world conditions and personal factors often make the results unreliable.

How accurate are field sobriety test results during DUI investigations?
Scientific studies show field sobriety test results can be inconsistent, with many sober individuals displaying clues officers mistakenly interpret as impairment, especially under stressful roadside conditions.

Can someone legally refuse a field sobriety test in California?
California law does not require taking a field sobriety test, and declining it carries no penalties, though officers may still decide to arrest.

Do field sobriety test mistakes affect the outcome of a DUI case?
Errors during field sobriety test administration can weaken prosecution arguments because improper instructions or environmental issues undermine the accuracy and reliability of observed clues.

How can a San Diego field sobriety test lawyer challenge police observations?
A lawyer reviews videos, reports, and testing procedures to expose inconsistencies, highlight improper administration, and argue that unreliable field sobriety test evidence should be limited or excluded.

When should someone contact a San Diego field sobriety test lawyer after arrest?
Immediate contact helps preserve video evidence, challenge DMV deadlines, and begin analyzing whether field sobriety test issues can significantly impact the DUI case outcome.

What does a San Diego field sobriety test lawyer evaluate in a DUI case?
The lawyer examines the traffic stop, officer training, environmental conditions, and specific field sobriety test clues to identify weaknesses that may reduce or dismiss charges.

How does a San Diego field sobriety test lawyer help fight DUI charges?
A lawyer challenges unreliable testing, questions officer conclusions, leverages legal protections, and builds defenses showing the field sobriety test performance does not prove impairment.

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Resources

California Vehicle Code § 23152 — Driving Under the Influence — This statute defines driving under the influence of alcohol, drugs, or both and explains what prosecutors must prove. It also shows how field sobriety test observations may relate to the statutory elements of a DUI charge.

NHTSA Standardized Field Sobriety Testing Refresher Manual — This source contains the national training materials used to teach officers how to administer and evaluate standardized field sobriety tests. It explains the purpose of the tests, testing procedures, observational guidelines, and limitations of field conditions. Readers can review this manual to understand how SFSTs are intended to be conducted and what factors may affect their reliability.

Evaluation of Field Sobriety Tests for Identifying Drivers Under the Influence of Cannabis — National Library of Medicine — This source summarizes a study evaluating the accuracy of field sobriety tests in identifying cannabis impairment. It discusses the study design, officer assessments, driving simulator outcomes, and findings about false positives among sober participants.

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Hire a Defense Attorney to Challenge Field Sobriety Tests in DUI Cases in San Diego County, CA

Field sobriety tests are often used by law enforcement to justify DUI arrests, but they are highly subjective and frequently unreliable. Poor instructions, uneven surfaces, medical conditions, fatigue, or nervousness can all cause a sober driver to appear impaired. Unchallenged field sobriety tests can lead to arrest, license suspension, and serious criminal consequences.

The Law Offices of Michael E. Cindrich provide experienced and strategic legal representation for individuals arrested for DUI based on field sobriety test performance. We analyze how the tests were administered, challenge improper procedures, and expose weaknesses in the officer’s conclusions to pursue the best possible outcome in your case.

Call (619) 262-2500 today for a free and confidential consultation to discuss your DUI defense options.