Being stopped for suspicion of DWI can be an overwhelming experience. One of the first things many drivers are asked to do is perform a series of roadside exercises commonly known as field sobriety tests. While officers often present these tests as straightforward measures of intoxication, the reality is much more complicated.
At The Law Office of Siara Ossa, PLLC, we regularly review police body camera footage, dash camera recordings, and officer testimony to determine whether field sobriety tests were properly administered. Many drivers are surprised to learn that these tests are governed by specific standards established by the National Highway Traffic Safety Administration (NHTSA), and that mistakes in administration can significantly affect the reliability of the results.
What Are Standardized Field Sobriety Tests?
The National Highway Traffic Safety Administration (NHTSA) developed the Standardized Field Sobriety Test (SFST) to assist law enforcement officers in determining whether a driver may be impaired by alcohol.
The word “standardized” is important. These tests are intended to be administered in a precise, uniform manner. Officers receive specialized training on the exact instructions they must provide, the specific clues they are trained to observe, and the scoring criteria for each test. According to NHTSA, deviations from the standardized procedures can affect the reliability of the tests.
Only three field sobriety tests have been validated by NHTSA:
- Horizontal Gaze Nystagmus (HGN)
- Walk-and-Turn (WAT)
- One-Leg Stand (OLS)
Although officers sometimes ask drivers to perform other roadside exercises—such as reciting the alphabet, counting backward, or touching a finger to the nose—those are not part of the standardized NHTSA, and not proven, scientifically, to indicate that a motorist is intoxicated.
The Three Standardized Field Sobriety Tests
1. Horizontal Gaze Nystagmus (HGN)
During the HGN test, the officer asks the driver to follow a stimulus, usually a pen or flashlight, using only their eyes.
The officer evaluates the motorists eyes for three possible clues:
- Lack of smooth pursuit
- Distinct and sustained nystagmus at maximum deviation
- Onset of nystagmus before 45 degrees
This produces a total of six possible clues. NHTSA associates four or more clues with impairment, but the test must be administered exactly as trained. Improper stimulus speed, incorrect positioning, poor lighting, or failure to account for medical conditions can undermine its reliability.
2. Walk-and-Turn Test
The Walk-and-Turn is considered a divided attention test because it requires a person to perform physical tasks while simultaneously following detailed instructions. So while the officer is looking for imbalance and unsteadiness, what they’re really looking for is the motorists ability to follow instructions and complete the tasks simultaneously.
The driver must:
- Place one foot directly in front of the other.
- Listen to the officer’s instructions.
- Walk nine heel-to-toe steps.
- Turn using a specific method.
- Return nine heel-to-toe steps.
Officers look for eight standardized clues, including stepping off the line, missing heel-to-toe, using the arms for balance, stopping while walking, and taking an incorrect number of steps. According to NHTSA, observing two or more clues is associated with impairment, but only when the test is administered under standardized conditions.
3. One-Leg Stand Test
The One-Leg Stand also measures divided attention.
The driver is instructed to:
- Raise one foot approximately six inches off the ground.
- Keep both legs straight.
- Look at the raised foot.
- Count aloud until instructed to stop.
The officer observes four possible clues:
- Swaying while balancing
- Using the arms for balance
- Hopping
- Putting the foot down
Numerous factors unrelated to alcohol—such as age, injuries, footwear, fatigue, uneven pavement, weather conditions, or medical issues—can affect a person’s ability to perform this test successfully.
Are Field Sobriety Tests Accurate?
Many people assume that failing a field sobriety test means they were intoxicated. That is not necessarily true. The standardized tests measure divided attention, balance, and eye movements—not intoxication itself. Many innocent factors can influence performance, including:
- Medical conditions
- Inner ear disorders
- Fatigue
- Anxiety
- Poor weather
- Uneven pavement
- Improper footwear
- Age
- Physical disabilities
- Officer error
Even under NHTSA’s own validation studies, the tests are not perfect predictors of impairment and are intended to assist officers in developing probable cause rather than conclusively determining guilt.
Can You Refuse Field Sobriety Tests in New York?
Unlike a chemical breath test requested after arrest under New York’s implied consent law, roadside field sobriety tests are generally voluntary. However, refusing to perform them does not necessarily prevent an officer from making an arrest if the officer believes other evidence establishes probable cause.
Why Proper Administration Matters
As defense attorneys, one of the first things we examine is whether the officer followed the standardized procedures taught during SFST training.
Common issues include:
- Improper instructions.
- Demonstrations that do not comply with training.
- Uneven or unsafe testing surfaces.
- Failure to ask about injuries or medical conditions.
- Rushing through the tests.
- Incorrect scoring.
- Body camera footage that contradicts the officer’s report.
These issues can become powerful evidence when challenging the officer’s conclusions.
Charged with DWI in New York?
If you have been arrested for DWI, field sobriety tests are only one piece of the prosecution’s case. Every detail—from the initial traffic stop to the administration of the SFSTs—should be carefully reviewed.
At The Law Office of Siara Ossa, PLLC, we represent clients throughout New York in DWI and related criminal matters. We carefully examine body camera footage, police reports, and officer testimony to determine whether field sobriety tests were administered correctly and whether the evidence can be challenged.
Just because an officer says you “failed” a field sobriety test does not mean the evidence will withstand scrutiny in court.
📞 Contact our office today to discuss your case and your options by calling or texting
347-733-5612.
www.ossalawny.com
siara@ossalawny.com