Field Sobriety Tests: What You Need to Know About Your Rights

Field Sobriety Tests (FSTs) are a common part of DUI investigations, but many people don't understand their rights regarding these tests. As former prosecutors, we've seen how these tests are administered and used in court, and we want to share crucial information that could protect you if you're ever in this situation.

Understanding Field Sobriety Tests

What Are Field Sobriety Tests?

Field Sobriety Tests are physical and cognitive exercises designed to help officers assess whether a driver is under the influence of alcohol or drugs. These tests are typically administered roadside during a DUI investigation.

Key Point: In California, field sobriety tests are voluntary for most drivers.

The Three Standardized Field Sobriety Tests

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

1. Horizontal Gaze Nystagmus (HGN)
2. Walk-and-Turn Test
3. One-Leg Stand Test

Let's examine each test in detail.

The Horizontal Gaze Nystagmus (HGN) Test

How the Test Works

The officer asks you to follow a stimulus (usually a pen or finger) with your eyes while keeping your head still. The officer looks for involuntary jerking of the eyes, called nystagmus.

What Officers Look For:

• Lack of smooth pursuit
• Distinct nystagmus at maximum deviation
• Onset of nystagmus prior to 45 degrees

Problems with the HGN Test

Medical Conditions: Many conditions can cause nystagmus unrelated to alcohol:

• Inner ear problems
• Brain injuries
• Certain medications
• Eye muscle fatigue
• Neurological disorders

Administration Errors: Common mistakes include:

• Improper stimulus speed
• Inadequate lighting
• Officer movement during test
• Failure to check for medical nystagmus

The Walk-and-Turn Test

Test Instructions

This "divided attention" test requires you to:

1. Stand heel-to-toe on a straight line
2. Take nine heel-to-toe steps down the line
3. Turn around using small steps
4. Take nine heel-to-toe steps back

What Officers Consider "Clues"

• Cannot keep balance during instructions
• Starts before instructions are finished
• Stops while walking
• Does not touch heel-to-toe
• Steps off the line
• Uses arms for balance
• Improper turn
• Wrong number of steps

Factors That Affect Performance

Physical Limitations:

• Age (people over 65 have difficulty)
• Weight (people over 30 pounds overweight struggle)
• Injuries or medical conditions
• Footwear (high heels, work boots)

Environmental Factors:

• Uneven or slippery surfaces
• Poor lighting
• Traffic noise and distractions
• Weather conditions

The One-Leg Stand Test

Test Procedure

You must:

1. Stand with feet together and arms at your sides
2. Raise one foot approximately 6 inches off the ground
3. Count out loud "one thousand one, one thousand two..." until told to stop
4. Keep your foot raised for 30 seconds

Observed "Clues"

• Swaying while balancing
• Using arms for balance
• Hopping to maintain balance
• Putting foot down

Reliability Issues

Physical Factors:

• Age and fitness level
• Medical conditions affecting balance
• Footwear and clothing
• Fatigue and stress

Test Conditions:

• Surface conditions
• Lighting and visibility
• Weather factors
• Officer instructions clarity

Your Rights Regarding Field Sobriety Tests

The Right to Refuse

Important: In California, you have the right to refuse field sobriety tests.

Key Points:

• Refusal cannot be used against you in court
• Officers may still arrest you based on other observations
• You should politely decline: "I respectfully decline to perform field sobriety tests"

Consequences of Refusal

What Won't Happen:

• No additional criminal charges
• No automatic license suspension
• Cannot be used as evidence of guilt

What Might Happen:

• Officer may arrest based on other observations
• Officer may request chemical testing
• May influence officer's decision to arrest

Non-Standardized Field Sobriety Tests

Common Non-Standardized Tests

Officers sometimes use additional tests not approved by NHTSA:

• Finger-to-nose test
• Alphabet recitation
• Counting backwards
• Finger counting
• Modified Romberg test

Problems with Non-Standardized Tests

• No scientific validation
• No standardized administration
• Highly subjective scoring
• Easily challenged in court

How Field Sobriety Tests Are Used in Court

Prosecution's Use

Prosecutors use FST results to:

• Establish probable cause for arrest
• Support DUI charges
• Demonstrate impairment level
• Counter defense arguments

Defense Challenges

Experienced defense attorneys challenge FSTs by:

Questioning Administration:

• Officer training and certification
• Compliance with standardized procedures
• Environmental conditions
• Proper instructions given

Medical and Physical Factors:

• Client's medical history
• Physical limitations
• Medication effects
• Fatigue and stress factors

Reliability Issues:

• Scientific validity of tests
• Error rates in ideal conditions
• Subjective nature of scoring
• Alternative explanations for "clues"

Strategies for Challenging Field Sobriety Tests

Documentation Review

We examine:

• Officer's training records
• Video evidence of test administration
• Police reports for inconsistencies
• Witness statements

Expert Testimony

We may use experts to explain:

• Proper test administration procedures
• Medical conditions affecting performance
• Scientific limitations of the tests
• Alternative explanations for observations

Cross-Examination Techniques

Effective cross-examination focuses on:

• Officer's training deficiencies
• Deviations from standard procedures
• Environmental factors affecting performance
• Subjective nature of observations

Medical Conditions That Affect FST Performance

Balance and Coordination Issues

• Inner ear disorders
• Vertigo and dizziness
• Arthritis and joint problems
• Back and leg injuries
• Neurological conditions

Vision Problems

• Eye muscle disorders
• Prescription medications
• Contact lens issues
• Age-related vision changes

Other Medical Factors

• Diabetes and blood sugar issues
• Anxiety and panic disorders
• Prescription drug side effects
• Sleep deprivation

What to Do If Asked to Perform Field Sobriety Tests

Recommended Response

1. Be polite and respectful
2. Clearly state your refusal: "I respectfully decline to perform field sobriety tests"
3. Ask for an attorney: "I would like to speak with my lawyer"
4. Don't argue or resist
5. Remember details for your attorney

What NOT to Do

• Don't attempt the tests if you have any doubt
• Don't argue about the validity of the tests
• Don't resist if arrested
• Don't discuss your drinking or activities

The Science Behind Field Sobriety Tests

NHTSA Validation Studies

The standardized tests are based on studies from the 1970s and 1980s:

• Original studies had significant limitations
• Controlled laboratory conditions don't reflect real-world scenarios
• Participant selection was not representative
• Error rates are higher in practice than in studies

Accuracy Claims vs. Reality

NHTSA Claims:

• HGN: 88% accurate
• Walk-and-Turn: 79% accurate
• One-Leg Stand: 83% accurate

Real-World Performance:

• Higher error rates in field conditions
• Subjective scoring affects accuracy
• Officer training variations impact results
• Environmental factors reduce reliability

Building a Strong Defense

Comprehensive Case Analysis

We examine every aspect of your case:

Pre-Test Factors:

• Reason for the traffic stop
• Officer observations before testing
• Your statements and behavior
• Environmental conditions

Test Administration:

• Officer qualifications and training
• Compliance with standardized procedures
• Video evidence analysis
• Witness observations

Post-Test Factors:

• Arrest procedures
• Chemical testing decisions
• Miranda rights compliance
• Evidence preservation

Alternative Explanations

We develop alternative explanations for FST performance:

• Medical conditions and medications
• Physical limitations and injuries
• Environmental factors and conditions
• Fatigue, stress, and anxiety
• Normal variations in performance

Conclusion

Field sobriety tests are not the reliable indicators of impairment that law enforcement claims them to be. These tests have significant limitations, high error rates, and are affected by numerous factors unrelated to alcohol consumption.

Understanding your rights is crucial. You have the right to refuse these voluntary tests, and refusal cannot be used against you in court. If you choose to perform the tests and are arrested, experienced legal representation can challenge the results effectively.

As former prosecutors, we understand how these tests are used by law enforcement and prosecutors. We also know their weaknesses and how to challenge them successfully in court. Every case is different, but with proper analysis and aggressive defense, FST evidence can often be excluded or minimized.

Don't let field sobriety test results determine your future. If you've been arrested for DUI, contact an experienced attorney who understands both the science and the law behind these tests. Your freedom and future may depend on it.