Getting pulled over for suspicion of DUI can be an unsettling experience. Many drivers are unaware that law enforcement officers now use standardized field sobriety tests (SFSTs) to determine impairment levels before making an arrest. If you’re facing DUI charges, you may be wondering, What impact does the new standardized field sobriety test have on DUI cases?
The new standardized field sobriety test has improved accuracy in detecting impairment but also raises concerns about reliability, officer discretion, and potential legal challenges.
As a DUI defense attorney with decades of experience handling impaired driving cases, I have seen how field sobriety tests can affect legal outcomes. In this article, I’ll explain the new standardized test, how it differs from previous methods, and what legal defenses you may have if you were arrested after undergoing an SFST.
What Are Standardized Field Sobriety Tests (SFSTs)?
Standardized Field Sobriety Tests (SFSTs) are a set of physical and cognitive tests police officers use to evaluate whether a driver is impaired.
The National Highway Traffic Safety Administration (NHTSA) developed SFSTs to provide law enforcement with a uniform method for assessing intoxication. The three primary tests include:
- Horizontal Gaze Nystagmus (HGN) Test – Observes involuntary eye movements when tracking an object.
- Walk-and-Turn (WAT) Test – Assesses balance, coordination, and ability to follow instructions.
- One-Leg Stand (OLS) Test – Evaluates a driver’s ability to maintain balance on one foot for a set duration.
These tests are meant to gauge physical and mental impairment caused by alcohol or drugs, but they are not foolproof.
What’s Different About the New Standardized Field Sobriety Test?
The new SFST includes improved testing protocols, additional impairment indicators, and updated officer training to increase reliability.
Key changes include:
- Enhanced training for law enforcement to improve administration and scoring accuracy.
- Updated testing procedures to factor in environmental conditions and medical conditions that may affect results.
- Stricter scoring criteria to reduce subjective interpretation and officer bias.
- Integration with body cameras to document performance and increase transparency.
While these updates aim to enhance DUI enforcement, they also create new legal questions about accuracy, officer discretion, and procedural errors.
Are Standardized Field Sobriety Tests Accurate?
Despite improvements, SFSTs are not 100% accurate and can result in wrongful DUI arrests.
- NHTSA studies show SFSTs are only 77%-88% accurate in identifying impairment.
- Medical conditions, fatigue, anxiety, and even footwear can affect test performance.
- Improper administration by officers can lead to false positives.
Because SFSTs are subjective, they remain vulnerable to human error and misinterpretation by law enforcement.
Can You Refuse a Field Sobriety Test?
Yes, in most states, you can legally refuse a field sobriety test without immediate penalties.
However, refusal may lead to:
- Increased suspicion from law enforcement.
- Possible arrest based on other observed behavior.
- Officers relying on breathalyzer or blood tests instead.
Unlike chemical tests (breath, blood, urine), SFSTs are not mandatory under implied consent laws, so refusal does not automatically result in license suspension.
Do Field Sobriety Tests Hold Up in Court?
Field sobriety tests can be challenged in court due to their subjective nature and high potential for officer error.
- Officers may improperly administer or interpret test results.
- Medical conditions, fatigue, or nervousness can cause false failures.
- Environmental factors like uneven pavement or bad weather can skew results.
- A skilled DUI attorney can challenge SFST results by highlighting inconsistencies, officer errors, or alternative explanations for a driver’s performance.
How Effective Is the SFST?
The Standardized Field Sobriety Test (SFST) is only 77%-88% accurate in detecting impairment, according to NHTSA studies.
- The Horizontal Gaze Nystagmus (HGN) test is about 88% accurate, but can be influenced by neurological conditions.
- The Walk-and-Turn (WAT) test is about 79% accurate, but balance issues can cause failures.
- The One-Leg Stand (OLS) test is about 83% accurate, but injuries or medical conditions may interfere with results.
- SFSTs are designed to detect impairment, but they are not foolproof and can result in wrongful arrests.
Why You Should Never Take a Field Sobriety Test
Field sobriety tests are highly subjective, not legally required in most states, and often provide evidence against you.
- Officers can use any minor mistake as justification for an arrest.
- Poor balance, medical conditions, or anxiety can cause failure—even if you’re sober.
- Refusing an SFST does not result in automatic penalties (unlike refusing a breathalyzer in implied consent states).
- If an officer asks you to take an SFST, it’s often best to politely decline and request legal counsel.
What Is the Problem With Field Sobriety Tests?
Field sobriety tests have a high failure rate and are influenced by subjective officer interpretation.
- Unreliable scoring – Officer bias or improper training can lead to incorrect assessments.
- External factors – Weather, uneven ground, footwear, and health conditions can impact performance.
- Non-standardized clues – Officers may interpret minor movements or hesitation as signs of impairment.
- SFSTs are not based on science alone; they rely heavily on officer judgment, making them susceptible to error and challenge in court.
Why Do Cops Do Field Sobriety Tests Instead of Breathalyzers?
Officers use field sobriety tests before a breathalyzer to establish probable cause for a DUI arrest.
- SFSTs allow officers to assess physical and cognitive impairment before administering a breath or blood test.
- Some jurisdictions require observable impairment before using a breathalyzer.
- If a driver fails an SFST, it strengthens the officer’s justification for an arrest.
- However, because SFSTs are subjective, they can lead to wrongful arrests that may be challenged in court.
What Is the Failure Rate of the Field Sobriety Test?
Field sobriety tests have a failure rate of approximately 20%-30%, even among sober individuals.
- HGN Test – 12% failure rate, often misinterpreted by officers.
- Walk-and-Turn Test – 21% failure rate, especially in individuals with balance issues.
- One-Leg Stand Test – 17% failure rate, affected by leg strength and coordination.
- Many sober individuals fail SFSTs due to nerves, poor conditions, or physical limitations.
How Do Field Sobriety Tests Affect DUI Cases?
SFST results are often used as key evidence in DUI cases, but they can be challenged in court.
- Officer error – If the test was improperly administered, the results may be inadmissible.
- Medical conditions – Certain medical conditions mimic signs of impairment, leading to false positives.
- Environmental factors – Poor lighting, uneven pavement, or bad weather can affect performance.
- Lack of standardization – Despite improvements, officer discretion can still lead to inconsistencies in scoring.
Legal Defenses Against Standardized Field Sobriety Tests
If you were arrested after an SFST, a DUI defense attorney can challenge the test results using several legal strategies.
- Improper Administration – If the officer did not follow standardized procedures, the test results may be invalid.
- Medical or Physical Conditions – Conditions like vertigo, neurological disorders, or injuries can impact test performance.
- External Interference – Poor weather, uneven roads, or footwear issues can cause false signs of impairment.
- Challenging Officer Observations – Bodycam footage and cross-examination can reveal inconsistencies in an officer’s assessment.
Key Takeaways
- The new standardized field sobriety test aims to improve accuracy but still has flaws.
- SFSTs are not mandatory in most states, and refusal may be an option.
- Medical conditions, environmental factors, and officer bias can lead to wrongful DUI arrests.
- DUI cases based on SFSTs can be challenged with the right legal defense.
Contact D.G. Moore Law for Expert DUI Defense
If you were arrested after taking a field sobriety test, D.G. Moore Law can help. As an experienced DUI defense attorney, I can challenge the validity of SFST results and build a strong case for your defense.
Don’t let a field sobriety test ruin your future—call us today at (269) 808-8007 for a free consultation.
Further Reading:
- What Happens After a DUI in Michigan?
- Do You Need a Lawyer for a DUI in Michigan?
- Can a DUI be Expunged in Michigan?
- How Long Does a DUI Stay on Your Record in Michigan?
Resources:
For more information on SFSTs and DUI defense, check out these authoritative sources:
- National Highway Traffic Safety Administration (NHTSA) – Field Sobriety Testing– Official guidelines on standardized field sobriety tests.
- American Bar Association (ABA) – DUI Defense Strategies – Legal guidance on defending against DUI charges.
- National Institute on Drug Abuse (NIDA) – Drug-Impaired Driving – How different substances affect driving ability.
