Field Sobriety Tests in New Jersey — Your Rights and How to Challenge Results

When a police officer suspects you of drunk driving in New Jersey, they will likely ask you to perform field sobriety tests on the side of the road. These tests are a major source of evidence in DWI cases. They are also frequently flawed.

At Papa Alpha & Alpha Law Firm in Springfield, NJ, we challenge field sobriety test results in DWI cases regularly. We know where these tests go wrong and how to use those failures in your defense.

The Three Standardized Field Sobriety Tests

The National Highway Traffic Safety Administration (NHTSA) recognizes three standardized field sobriety tests (SFSTs). These are the only tests validated by scientific research. New Jersey officers are trained to administer these three tests:

Horizontal Gaze Nystagmus (HGN)

The officer holds a stimulus — usually a pen or small flashlight — about 12 inches from your face and moves it slowly from side to side. They are watching for involuntary jerking of the eye (nystagmus) that can indicate alcohol impairment.

The officer looks for three clues in each eye:

1. Lack of smooth pursuit (the eye jerks instead of following smoothly)
2. Distinct nystagmus at maximum deviation (jerking when the eye is held to one side)
3. Onset of nystagmus before 45 degrees (jerking begins before the eye moves 45 degrees from center)

The HGN test is considered the most reliable SFST, but it has significant limitations. Nystagmus can be caused by medical conditions, fatigue, medications, and even caffeine.

Walk-and-Turn Test

You are instructed to walk nine steps in a straight line, heel-to-toe, turn in a specific manner, and walk nine steps back. The officer watches for eight clues of impairment:

1. Cannot keep balance during instructions
2. Starts too soon
3. Stops while walking
4. Does not touch heel to toe
5. Steps off the line
6. Uses arms for balance
7. Improper turn
8. Wrong number of steps

Two or more clues indicate impairment according to NHTSA research. But this test is performed on a roadside — often at night, in traffic, on uneven pavement, in bad weather. These conditions make it unreliable for many sober people.

One-Leg Stand Test

You must stand on one foot with the other foot raised approximately six inches off the ground while counting out loud for 30 seconds. The officer looks for four clues:

1. Swaying while balancing
2. Using arms for balance
3. Hopping
4. Putting the foot down

Two or more clues indicate impairment. But age, weight, footwear, injuries, and medical conditions all affect a person's ability to balance on one foot for 30 seconds.

Your Right to Refuse Field Sobriety Tests

Here is what many people do not know: you are not legally required to perform field sobriety tests in New Jersey. These tests are voluntary. You can politely decline.

This is different from the breath test. New Jersey's implied consent law requires you to submit to a breath test, and refusing carries its own penalties. But field sobriety tests are not covered by implied consent.

Refusing field sobriety tests cannot be used against you in court as evidence of guilt. However, the officer may still arrest you based on other observations — odor of alcohol, slurred speech, erratic driving.

Why Field Sobriety Tests Are Unreliable

NHTSA's own research shows that field sobriety tests are far from perfect:

• HGN test: 77% accurate at identifying BAC above 0.10%
• Walk-and-turn: 68% accurate
• One-leg stand: 65% accurate
• All three combined: 82% accurate

That means even under controlled research conditions, nearly 1 in 5 people identified as impaired by all three tests are actually sober.

In real-world roadside conditions, accuracy drops further. Officers administer these tests on highway shoulders, in parking lots, and on uneven sidewalks. Bright headlights, flashing police lights, and the stress of being stopped all affect performance.

Common Factors That Produce False Results

Many conditions other than alcohol impairment cause people to fail field sobriety tests:

• Age over 65 — balance and coordination naturally decline
• Weight over 50 pounds above ideal — affects balance tests
• Back, leg, or inner ear problems — directly impact walking and standing tests
• Prescription medications — many medications affect balance without causing impairment
• Fatigue — being tired mimics signs of intoxication
• Footwear — high heels, work boots, and sandals make balance tests harder
• Road conditions — gravel, slopes, cracks, and wet surfaces
• Nervousness — the stress of a police encounter affects performance
• Vision problems — contact lenses and certain eye conditions affect the HGN test

How We Challenge Field Sobriety Test Results

Review the Dashcam and Bodycam Footage

Video evidence often tells a different story than the police report. We compare the officer's written observations to what the footage actually shows. Officers sometimes describe clues that are not visible on video.

Examine Officer Training and Administration

NHTSA requires officers to administer the tests in a specific, standardized way. If the officer deviated from the protocol — gave incorrect instructions, used a non-standard surface, or failed to demonstrate properly — the results are unreliable.

Identify Medical and Physical Explanations

We gather medical records and, when necessary, retain experts to explain how physical conditions, medications, or other factors caused the test failures.

Challenge the Officer's Interpretation

Field sobriety test scoring is subjective. What one officer calls "swaying" another might consider normal movement. We cross-examine officers on their observations and scoring to expose inconsistencies.

Do Not Assume the Tests Prove Anything

Field sobriety tests are tools — imperfect ones. They are starting points for the prosecution, not proof of guilt. A skilled DWI attorney knows how to dismantle them.

Call Papa Alpha & Alpha Law Firm at (201) 555-0100 for your free consultation. We defend clients facing DWI charges in Springfield, Union County, and throughout New Jersey.