Are Florida’s Field Sobriety Tests Rigged? Here’s What the Data Actually Shows.
If your kid gets an 80 on a test, they pass. Some parents are ecstatic with 80. In a DUI stop, the field sobriety exercises work nothing like that. If you get 73 things right and 4 things wrong, the officer scores only what you did wrong. All 73 correct responses disappear. The result says you failed. That’s the first reason I’ve been telling people for over 33 years not to take these exercises.
I want to pull back the curtain on exactly why these tests are not what the state claims them to be, because the moment you understand what’s actually happening on the side of that road, you’ll understand why your decision about whether to take these exercises matters so much.
Stopped for DUI and Asked to Do Field Sobriety Exercises?
These exercises are optional in Florida. Refusing them removes one of the most subjective pieces of evidence from the state’s case. Call John Guidry at (407) 423-1117 before you assume you have to do them.
The Scoring Is One-Sided by Design
Take the walk-and-turn as an example. That test has 77 potential clues — things an officer observes about how you perform each element. Most of those clues, when present, indicate sobriety. If you perform 73 of them correctly and stumble on 4, the officer makes a laundry list of your 4 failures. The 73 correct responses don’t appear in the police report. The state doesn’t present them to the jury. Your defense attorney eventually finds out what you did right, but by then the arrest report has sat in a file for months, written entirely in the language of impairment.
This is not a balanced evaluation. It’s a collection mechanism for reasons to arrest. The officer arrives at the test already suspecting you’re impaired, and the scoring structure confirms that suspicion regardless of how much of it you got right.
NHTSA’s Own Numbers Should Disqualify These Tests
Here’s the part that genuinely astounds me, even after 33 years. The state calls these tests scientific. Their validation research comes from NHTSA — the National Highway Traffic Safety Administration. And NHTSA’s own studies from Tharp, Burns, and Moskowitz (1981) show the following misclassification rates when these tests run under controlled conditions:
The Horizontal Gaze Nystagmus test misclassifies sober people as impaired 23% of the time. The Walk-and-Turn test misclassifies sober people 32% of the time. The One-Leg Stand misclassifies sober people 35% of the time.
Think about what 35% means. Imagine a bottle of Tylenol where 35 of the 100 pills contain poison. Nobody buys that bottle. Nobody takes those pills. If a breathalyzer returned a result that was wrong a third of the time, courts would throw it out immediately. But somehow, a test with a 35% error rate — confirmed by the very agency that created and validates it — continues to determine whether people go to jail.
The reason isn’t science. The reason is that these tests generate probable cause to arrest. They accomplish the goal. The science is secondary.
The Conditions Are Never Controlled
There’s a third problem that gets less attention than it deserves. Scientific tests require controlled conditions. You don’t run a medical trial in a parking lot at 2 a.m. with an anxious subject, bad lighting, uneven pavement, and no standardized surface to walk on.
Since 1993, I’ve watched officers attempt the walk-and-turn on asphalt with invisible lines, imaginary lines, or lines they draw verbally with no defined width. I’ve seen clients fail because they stepped “off the line” — a line the officer described but never marked, with no specification of how wide it was or how precise the steps needed to be. When I watch the body cam video later, the officer’s instructions were vague, the line never existed, and my client is now in a police report described as someone who “failed to maintain the line.”
That’s not science. That’s an officer’s opinion dressed up in a scientific-sounding name.
These Exercises Are Optional — Don’t Forget That
Unlike the breathalyzer, which Florida law now requires you to take under Trenton’s Law (effective October 1, 2025), the field sobriety exercises remain entirely voluntary. Refusing them carries no criminal penalty. Officers don’t always make that clear, and some will tell you — incorrectly — that you have to do them. You don’t.
Declining the exercises takes a biased, poorly controlled, officer-opinion-based evaluation out of the state’s evidence file. It doesn’t prevent the arrest. If an officer has already decided you’re impaired, they’ll arrest you based on their observations from the traffic stop alone. But it does prevent one of the most unreliable pieces of evidence from becoming part of the narrative that follows your case into a courtroom.
If You Want More Related Content
Check out our more videos and breakdown articles covering major updates in Florida defense law. You can also use the links below to stay informed. Learn how to protect your constitutional rights when dealing with law enforcement.
Watch: Why You Should Refuse Field Sobriety Tests?
Read: https://jgcrimlaw.com/articles/empty-beer-cans-florida-dui-defense/
John’s Takeaways
- Field sobriety exercises are not scored fairly. Only failures count. Everything you do correctly disappears from the evaluation.
- NHTSA’s own research confirms error rates of 23% for HGN, 32% for Walk-and-Turn, and 35% for One-Leg Stand. These aren’t defense attorney statistics — they come from the agency that created and validates the tests.
- The conditions on a roadside at night bear no resemblance to controlled scientific testing. Imaginary lines, uneven surfaces, anxiety, and subjective officer scoring all undermine any claim of scientific reliability.
- Field sobriety exercises are optional in Florida. Unlike the breathalyzer under Trenton’s Law, declining them carries no criminal penalty.
- These tests exist to generate probable cause to arrest, not to determine scientific truth. A defense attorney who understands this can challenge their results effectively — but the best outcome is never giving the state this evidence in the first place.
Facing a DUI After Failing Field Sobriety Exercises? Let’s Look at What Actually Happened.
I’ve been challenging field sobriety results in Central Florida since 1993, and I know exactly where these tests break down. I represent clients across Orange, Seminole, Osceola, Lake, Brevard, and Volusia County.
If you took these exercises and didn’t like how they turned out, give my office a call. The error rates are real, and so are the defenses.
John Guidry — (407) 423-1117
About John Guidry II
John Guidry II is a seasoned criminal defense attorney and founder of the Law Firm of John P. Guidry II, P.A., located in downtown Orlando next to the Orange County Courthouse, where he has practiced for over 33 years. With more than three decades of experience defending clients throughout Central Florida since 1993, Guidry has successfully defended thousands of cases in Orange, Seminole, Osceola, Brevard, Lake, and Volusia counties. He has built a reputation for his strategic approach to criminal defense, focusing on pretrial motions and case dismissals rather than jury trials.
John Guidry earned both his Juris Doctorate and Master of Business Administration from St. Louis University in 1993. He is a member of the Florida Bar and the Florida Association of Criminal Defense Lawyers. His practice encompasses the full spectrum of Florida state criminal charges, with a particular emphasis on achieving favorable outcomes through thorough pretrial preparation and motion practice.
Beyond the courtroom, Guidry is a prolific legal educator who has authored over 400 articles on criminal defense topics. He shares his legal expertise through his popular YouTube channel, Instagram, and TikTok accounts, where he has built a substantial following of people eager to learn about the law. His educational content breaks down complex legal concepts into accessible information for the general public.
When not practicing law, Guidry enjoys tennis and pickleball, and loves to travel. Drawing from his background as a former recording studio owner and music video producer in the Orlando area, he brings a creative perspective to his legal practice and continues to apply his passion for video production to his educational content.