What Every Bexar County Driver Should Know About SFSTs
Facing a DWI stop in San Antonio can be intimidating—especially when an officer asks you to perform Standardized Field Sobriety Tests (SFSTs). These roadside exams—like the Horizontal Gaze Nystagmus, Walk‑and‑Turn, and One‑Leg Stand—are designed by the National Highway Traffic Safety Administration (NHTSA) to quickly assess impairment, but they’re far from foolproof. Variables such as uneven pavement, poor lighting, pre‑existing medical conditions, or simple nerves can skew your performance and give officers a false basis for arrest. That’s why understanding how SFSTs are properly administered—and knowing when and how to challenge flawed results—is critical to protecting your driving privileges, avoiding harsh penalties, and safeguarding your future in Bexar County. If you face a DWI stop on Loop 410, Broadway, or anywhere in San Antonio, a seasoned DWI defense attorney can review every detail of your roadside exam, expose procedural errors, and mount a robust defense on your behalf.
What Are SFSTs?
SFSTs are a battery of three tests approved by the National Highway Traffic Safety Administration (NHTSA) to help law enforcement evaluate whether a driver is impaired. The three core SFSTs are:
- Horizontal Gaze Nystagmus (HGN): Observing involuntary eye jerking as you follow a moving object.
- Walk-and-Turn (WAT): A nine‑step, heel‑to‑toe walk in a straight line, turn, and return.
- One‑Leg Stand (OLS): Balancing on one leg for about 30 seconds while counting aloud.
These tests are standardized nationwide to ensure consistency, but factors like medical conditions, uneven surfaces, and nerves can lead to false “fail” indicators.
How SFSTs Are Administered in San Antonio & Bexar County
When you’re pulled over anywhere in Bexar County—from Leon Valley and Alamo Heights to Stone Oak or Downtown—officers must follow strict NHTSA protocols before asking you to perform Standardized Field Sobriety Tests (SFSTs). Here’s what typically happens during a San Antonio DWI stop:
- Traffic Stop on Major Thoroughfares
Whether you’re driving on I‑10, Loop 410, Broadway Avenue, or any San Antonio surface street, an officer may initiate a stop for alleged unsafe driving behaviors—swerving, speeding, or equipment violations. - Pre‑Test Observation
Before administering SFSTs, the officer will watch for visible signs of impairment: bloodshot eyes, slurred speech, the odor of alcohol, or unsteady gait. These observations establish “probable cause” for the SFST battery.
Administering the SFST Battery
During a traffic stop anywhere in Bexar County—whether on I‑10, Loop 410, or Broadway in San Antonio—officers may ask you to perform three NHTSA‐approved roadside exercises to gauge impairment:
- Horizontal Gaze Nystagmus (HGN): You follow a slowly moving object (pen, flashlight, or finger) with your eyes. The officer checks for involuntary eye jerking at specific angles—up to six possible “clues.” Four or more clues typically signal impairment.
- Walk‑and‑Turn (WAT): You take nine heel‑to‑toe steps along an imaginary straight line, execute a controlled pivot, and return. The officer notes eight possible clues—like stepping off the line, balance issues, or an improper turn. Two or more clues usually constitute failure.
- One‑Leg Stand (OLS): You balance on one foot about six inches off the ground and count aloud for 30 seconds. The officer observes for up to four clues—swaying, using arms for balance, hopping, or setting the foot down. Two or more clues often indicate impairment. https://www.nhtsa.gov/risky-driving/drunk-driving/field-sobriety-tests
Performance Evaluation & Arrest Decision
After you complete all three exercises, the officer tallies your total “clues.” Exceeding the NHTSA fail thresholds—four HGN clues, two WAT clues, or two OLS clues—can give the officer legal grounds to arrest you for DWI in San Antonio. However, environmental conditions (uneven pavement, poor lighting) or medical issues (inner‑ear disorders, injuries) can generate false clues. That’s why an experienced San Antonio DWI defense team will meticulously review officer training records, scene photos, and dash‑cam footage to challenge any procedural errors and protect your rights in Bexar County.
Because factors like uneven pavement, poor lighting, or medical conditions can skew your results, it’s crucial to have a seasoned San Antonio DWI defense lawyer review every step of your stop. At Ried Pecina Trial Lawyers, we analyze officer training records, scene photos, and dash‑cam footage to spot procedural errors. Learn more about our criminal defense services or call us at (210) 893‑0000 for a free consultation—available 24/7 throughout Bexar County.
Common SFST “Clues” & How They’re Scored
| Test | Maximum “Clues” | Typical Fail Threshold |
| Horizontal Gaze | 6 | 4* |
| Walk-and-Turn | 8 | 2 |
| One‑Leg Stand | 4 | 2 |
Challenging SFST Results
Beat unfair SFST outcomes by:
- Questioning Officer Training: Was the officer certified in NHTSA SFST procedures?
- Highlighting Environmental Factors: Poor weather, traffic, or uneven pavement can invalidate results.
- Medical & Physical Issues: Inner‑ear conditions, orthopedic injuries, or age‑related balance problems are valid defenses.
- Video & Witness Evidence: Many San Antonio traffic stops are recorded. Review dash‑cam footage for improper instructions or demonstrations.
Our team at Ried Pecina Trial Lawyers meticulously examines every SFST nuance to identify procedural errors that can lead to reduced charges or even case dismissal.
Why You Need a San Antonio DWI Attorney
A local DWI defense lawyer:
- Reviews SFST protocols and officer training records
- Engages expert witnesses (e.g., pharmacologists, medical professionals)
- Represents you at DPS license‑suspension hearings
- Negotiates favorable plea deals when appropriate
Whether you were stopped near Tri Point, Medical Center, Southside, or Northwest Salado Creek, our Bexar County attorneys have you covered.
FAQs About SFSTs in Bexar County
Q1: Are SFSTs mandatory?
No—officers request consent. You can politely decline, though refusal may lead to arrest or implied‑consent penalties.
Q2: Do courts accept SFSTs as conclusive evidence?
SFSTs are admissible, but defense counsel frequently files motions to exclude flawed SFST evidence.
Q3: What if I failed SFSTs but passed a breath test?
SFST performance is just one piece of evidence. Passing a breathalyzer (below 0.08% BAC) can be a strong defense.
Call (210) 893‑0000 today!
Don’t let a few missteps on a roadside test determine your future. If you’ve been asked to perform SFSTs in Bexar County, contact Ried Pecina Trial Lawyers for aggressive, experienced defense.
Call us now at (210) 893‑0000 for a free, no‑obligation consultation. We’re available 24/7 to protect your driving privileges and fight for the best possible outcome.
Related Links
External Resources
- NHTSA Drunk Driving: https://www.nhtsa.gov/risky-driving/drunk-driving
- Texas Department of Public Safety Alcohol-Related Offenses: https://www.dps.texas.gov/section/driver-license/alcohol-related-offenses
Ried Pecina Trial Lawyers – Your best defense against DWI charges in San Antonio, Bexar County, and surrounding communities. Call (210) 893‑0000 today!