Field Sobriety Tests in California: Can You Legally Refuse? | Shrout Law

The short answer: Yes, in most cases you can refuse field sobriety tests (FSTs) in California without automatic legal penalties. However, understanding the full picture is important for making an informed decision.

What Are Field Sobriety Tests?

Field sobriety tests are physical and cognitive exercises that officers use to assess whether a driver may be impaired. They are conducted roadside, before an arrest, as part of the DUI investigation process.

The Three Standardized Tests (SFSTs)

The National Highway Traffic Safety Administration (NHTSA) has validated three standardized tests:

Horizontal Gaze Nystagmus (HGN)

The officer moves a stimulus (pen, finger, or light) horizontally across your field of vision while watching for involuntary jerking of the eyes. Alcohol can cause exaggerated nystagmus.

Walk-and-Turn

You walk nine heel-to-toe steps along a straight line, turn on one foot, and return nine steps while counting out loud. Officers watch for eight specific "clues" of impairment.

One-Leg Stand

You stand on one foot with the other raised about six inches off the ground while counting out loud for 30 seconds. Officers look for swaying, hopping, or putting your foot down.

Can You Refuse Field Sobriety Tests?

You CAN Refuse

• Field sobriety tests (HGN, walk-and-turn, one-leg stand)
• Preliminary Alcohol Screening (PAS) breath test
• Non-standardized tests (alphabet, finger count)
• No automatic penalty for refusal

Exceptions

• Under 21 years old (zero tolerance)
• Currently on DUI probation
• Post-arrest chemical test (implied consent)
• Refusal may still lead to arrest

Important Distinction

FSTs are pre-arrest investigation tools. The post-arrest chemical test (breath or blood at the station) is not voluntary under California's implied consent law.

Problems with Field Sobriety Tests

Even NHTSA's own research shows FSTs are far from perfect indicators of impairment:

Test	Accuracy Rate	False Positive Rate
HGN	77%	23%
Walk-and-Turn	68%	32%
One-Leg Stand	65%	35%

Factors That Can Affect Performance

Age (over 65)

Weight (50+ lbs overweight)

Physical disabilities

Inner ear conditions

Back, leg, or knee problems

Certain medications

Footwear (heels, boots)

Road surface conditions

Weather (wind, rain)

Nervousness or anxiety

Fatigue

Poor lighting

What Happens If You Refuse?

If you politely decline FSTs:

The officer may still arrest you based on other observations
Your refusal may be mentioned in the police report
There is no automatic license suspension for FST refusal
Prosecutor may argue "consciousness of guilt" at trial

How to Politely Refuse

If you choose to refuse, remain calm and polite:

"Officer, I understand you're doing your job. I respectfully decline to perform field sobriety tests. I'm not trying to be difficult, but I don't believe these tests are in my best interest."

For comprehensive information about DUI defense, visit our California DUI Defense page.

Key Takeaways

Pre-arrest FSTs are voluntary for most drivers in California
Exceptions exist for those under 21 or on DUI probation
FSTs have significant accuracy limitations
Post-arrest chemical tests are NOT voluntary (implied consent)

Know your rights before you're ever pulled over.

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