If you are pulled over on suspicion of Driving Under the Influence (DUI) under California Vehicle Code § 23152, an officer's request to perform field sobriety tests (FSTs) is often terrifying. Most drivers wonder whether passing these tests is actually possible or if they are simply designed to build a case against them.
While drivers can theoretically pass field sobriety tests, FSTs are highly subjective, deeply flawed, and often conducted under unfair conditions. In reality, law enforcement officers often use FSTs to collect evidence supporting an arrest rather than to confirm sobriety.
The Reality of Field Sobriety Tests (FSTs)
Field sobriety tests consist of physical and cognitive exercises designed to test multi-tasking abilities, balance, and physical coordination.
While the National Highway Traffic Safety Administration (NHTSA) sets national standards for these tests, officers do not always administer them correctly, and California courts do not strictly mandate compliance with federal guidelines.
The typical process surrounding field sobriety testing unfolds across several stages:
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Traffic Stop & Initial Suspicion: An officer pulls a driver over based on reasonable suspicion of a traffic violation or impaired driving behavior.
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Voluntary FST Request: The officer asks the driver to step out of the vehicle and perform roadside physical and cognitive exercises.
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Submitting vs. Refusing: If a driver submits, the officer observes specific "clues" of impairment to build a criminal case. If a driver politely refuses, they prevent the prosecution from collecting subjective physical coordination evidence against them.
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Arrest & Chemical Testing: Regardless of FST performance, if the officer decides to arrest the driver, the driver must submit to a mandatory post-arrest chemical test (breath or blood) under California's Implied Consent law.
Why FSTs Are Inherently Flawed
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Unfavorable Roadside Conditions: FSTs are rarely administered in ideal environments. Flashing police lights, passing highway traffic, uneven pavement, poor lighting, and cold weather routinely impair performance—even for completely sober drivers.
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Physical & Medical Factors: Pre-existing injuries, joint pain, inner ear conditions, age, weight, or extreme anxiety can cause a driver to fail physical coordination exercises.
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Subjective Evaluation: Officers actively search for specific "clues" indicating impairment. Because officer evaluations are subjective, police reports often omit positive performance factors.
Standardized vs. Non-Standardized Field Sobriety Tests
Law enforcement agencies in Los Angeles and across California utilize both NHTSA-approved "standardized" tests and unapproved "non-standardized" roadside exercises.
|
Test Category |
Test Name |
Performance Objective & Evaluation Criteria |
| Standardized (NHTSA) | Horizontal Gaze Nystagmus (HGN) | Officers sweep a pen or light horizontally across vision to detect "nystagmus" (involuntary eye jerking). |
| Standardized (NHTSA) | Walk-and-Turn | Drivers walk heel-to-toe along a straight line, pivot, and walk back while counting out loud. |
| Standardized (NHTSA) | One-Leg Stand | Drivers stand on one foot six inches off the ground and count out loud to assess balance and attention. |
| Non-Standardized | Finger-to-Nose | Drivers close their eyes, tilt their head back, and attempt to touch their nose using alternate index fingers. |
| Non-Standardized | Alphabet Test | Drivers must recite the alphabet aloud—or recite a specific section (e.g., "D to S")—without singing. |
Can You Refuse Field Sobriety Tests in California?
Yes. Under California law, roadside field sobriety tests are strictly voluntary.
Drivers may legally decline pre-arrest roadside physical exercises without incurring direct administrative penalties or driving license suspensions for the refusal itself.
Crucial Legal Distinction: Pre-arrest field sobriety tests differ from post-arrest chemical tests. Under California Vehicle Code § 23612 (Implied Consent Law), once legally arrested for a DUI, drivers must submit to a chemical breath or blood test. Refusing a post-arrest chemical test triggers mandatory license suspensions and enhanced criminal penalties.
Defense Strategies to Challenge FST Results
A skilled criminal defense attorney can challenge field sobriety test evidence in court using several legal strategies:
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Challenging Officer Administration: Demonstrating that the officer failed to follow standard NHTSA protocols when giving test instructions.
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Proving Environmental Distractions: Using bodycam and dashcam footage to show that environmental factors (unlevel ground, darkness, traffic) caused poor performance.
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Introducing Medical Alternatives: Presenting medical records establishing that physical limitations, fatigue, or medical conditions caused poor balance or abnormal eye movement.
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Exposing Lack of Probable Cause: Arguing that the officer lacked initial reasonable suspicion or probable cause to conduct a traffic stop.
Frequently Asked Questions (FAQs)
Are field sobriety tests mandatory in California?
No. Pre-arrest roadside field sobriety tests are voluntary in California. You have the legal right to decline participating in physical FSTs without receiving an automatic license suspension.
Will I be arrested if I refuse field sobriety tests?
Refusing an FST does not prevent an officer from making an arrest. An officer can still arrest you based on other observations, such as driving patterns, slurred speech, or the odor of alcohol. However, declining the test limits the prosecution's physical evidence against you.
What is the difference between a Preliminary Alcohol Screening (PAS) test and a chemical test?
A PAS breath test conducted at the roadside before an arrest is generally voluntary for drivers age 21 or older not on DUI probation. Mandatory chemical testing (station breath or blood tests) applies after an arrest occurs under California's Implied Consent Law.
Why do completely sober people fail field sobriety tests?
Sober individuals frequently fail FSTs due to extreme nervousness, fatigue, physical injuries, poor footwear, bad lighting, or uneven roadside terrain.
What are the main penalties for a California Vehicle Code 23152 DUI conviction?
Penalties depend on factors like prior offenses, blood alcohol concentration (BAC), or injuries. Standard penalties include driver's license suspension, community service, DUI school, probation, monetary fines, and potential jail time.
How does an attorney challenge field sobriety test evidence?
Defense attorneys scrutinize officer bodycam footage, challenge improper test administration, present medical records explaining poor balance, and expose environmental distractions that invalidated the test results.
Facing DUI Charges in Southern California?
If you were arrested after performing DUI field sobriety tests, having an experienced defense attorney review your case is critical. Contact Cron, Israels & Stark for a free case evaluation at (424) 372-3112.
