Don’t Let a Traffic Stop Dictate Your Future
You’re pulled over late at night. The officer asks if you’ve had anything to drink. Next thing you know, you’re standing on one leg, walking heel-to-toe, and following a pen with your eyes. Then you hear those dreaded words: “You’re under arrest.”
Sound familiar?
Just because you “failed” a field sobriety test doesn’t mean you’re guilty. At the Marc Lopez Law Firm, we love breaking down these tests, exposing their flaws, and showing why the State’s case isn’t nearly as airtight as they think.
10 Proven Ways We Attack Field Sobriety Tests in Indiana
1. Sloppy Test Administration—If It’s Not Done by the Book, It Doesn’t Count
Field sobriety tests only matter if they’re administered exactly as prescribed by the National Highway Traffic Safety Administration (NHTSA). That’s not optional—it’s the whole point of “standardized.”
Officers often botch the Horizontal Gaze Nystagmus (HGN), failing to hold the stimulus the proper distance or angle from the suspect’s eyes. The manual says it needs to be 10–15 inches away, slightly above eye level. There are timing patterns, pre-test positioning steps, and criteria for clues that have to be followed to the letter.
We regularly bring officers into depositions and ask them to demonstrate the test. That’s when things fall apart. “I usually use a cheat sheet,” they’ll say. “I don’t remember every step off the top of my head.” If they can’t do it correctly in a quiet conference room, how did they get it right on a highway shoulder at 2 a.m.?
When the instructions aren’t followed, the test isn’t valid—and we make sure everyone in the courtroom understands that.
2. Unfair Testing Conditions—Roadside Isn’t a Laboratory
Standardized field sobriety tests were designed under controlled laboratory conditions: flat surfaces, no noise, ideal lighting. That’s not what you get on a gravel shoulder with headlights in your face and traffic buzzing by.
We examine the video. Were you standing on a slope? Was the officer yelling instructions over semi-truck noise? Were you wearing heels, boots, or sandals? Were you walking barefoot because the officer suggested you take your shoes off?
What about the flashing lights—those red and blue disco strobes from squad cars? They can induce optokinetic nystagmus, a fancy term for involuntary eye twitching. Some officers are trained to turn those lights off during the HGN, but many don’t. Add passing traffic and ambient chaos, and the idea that this is some sort of reliable test goes out the window.
These aren’t minor details. They’re critical flaws. And we love pointing them out.
3. Medical Explanations—The Body Doesn’t Lie, But It Might Mislead
We dig into your medical history, because the body doesn’t always behave “normally”—especially when it’s dealing with injuries, age, or chronic conditions.
Nystagmus (the jerking eye movement officers look for in the HGN test) can result from over 40 different causes—alcohol is just one of them. Inner ear infections, neurological issues, certain medications, head injuries—any of these could create HGN clues.
What about the walk-and-turn or the one-leg stand? The manual itself warns that elderly individuals and those 50+ pounds overweight are more likely to fail. Add in common problems like arthritis, old sports injuries, balance disorders, or anxiety, and those results become meaningless.
We love when a client’s health history paints a clearer picture than the officer’s assumptions. Because if your performance had nothing to do with impairment, then the test shouldn’t be used against you.
4. Subjective Judgments—When “Evidence” Is Just an Opinion
Swaying? Raising arms “more than two inches”? Failing to “pivot correctly”? These aren’t cold, hard facts. They’re the officer’s personal interpretations.
Two inches to you might not be two inches to them. A slight step to regain balance could be seen as a “clue.” And if an officer is grading a test while glancing at a cheat sheet—or from memory—they’re not watching you. That’s not how these tests are supposed to work.
We ask the officer to demonstrate how they instructed our client. “Show us what you meant by ‘swaying.’ Show us the turn.” Half the time, they can’t explain it in a consistent way, and the other half, they make it up on the fly.
Subjective interpretation opens the door for bias, mistakes, and sloppy assumptions. We hammer that door open and walk right through it.
5. Outdated or Incomplete Training—The Rusty Tool Problem
Field sobriety testing is a skill, not a one-time lecture. And like any skill, it gets rusty over time.
We ask officers about their training. What year did they get certified? Have they had refresher courses since then? Were they using the current NHTSA manual or an outdated version?
Even if the basics haven’t changed drastically, minor updates do occur—and the best officers stay sharp. When an officer hasn’t refreshed their training in years but still claims to be doing everything by the book, we call that into question. If they’ve had updated training and still get it wrong, that’s even better for us.
Because at the end of the day, if they can’t follow the rules, why should a jury trust their results?
6. Everyday Behavior Misread as “Impairment”
“Red eyes.” “Nervous.” “Unsteady exit.” We hear these phrases all the time. The State treats them like silver bullets. We treat them like meaningless fluff.
It’s 2 a.m. You’ve worked a double shift. You’re exhausted, stressed, and now there are flashing lights behind you. Who wouldn’t be nervous? Who wouldn’t stumble out of a tall vehicle in the dark wearing tight jeans?
It’s not illegal to smell like alcohol. It’s not illegal to be tired, anxious, or clumsy. Officers often mistake normal, explainable human behavior for signs of impairment. We reframe the narrative—and show that what the officer saw has nothing to do with alcohol.
7. Missing Video—Convenient, Isn’t It?
Most departments have body cams and dash cams these days. But somehow, when it comes to field sobriety tests, the footage is often missing.
“Oh, the camera malfunctioned.”
“Oh, I stood in front of the cruiser for safety.”
“Oh, the recording didn’t save.”
Convenient.
If these tests are so essential to the State’s case, where’s the footage? If the stop was justified and the tests were administered correctly, why don’t we have it on tape?
We highlight these gaps and raise the question: what’s the State hiding? Because the absence of evidence doesn’t mean the officer is right. It means their credibility just took a hit.
8. Garbage Tests Produce Garbage Results
There are only three standardized field sobriety tests:
- Horizontal Gaze Nystagmus (HGN)
- Walk-and-Turn
- One-Leg Stand
That’s it. Everything else is junk science.
We’ve had officers testify that someone failed because they couldn’t say the alphabet backward. Newsflash: that’s not a real test. No lab validated it. No manual recommends it.
Same goes for counting backwards from arbitrary numbers or weird finger-touch exercises. These aren’t sobriety tests—they’re gotcha games. And if the State is relying on these to convict you, we’re going to shine a spotlight on that garbage until the court sees it for what it is.
9. Failing to Consider Medical or Mental Conditions
There’s a huge difference between impairment from alcohol and impairment from a medical issue. But when officers are hunting DUIs, they often don’t care.
Was your client diabetic and showing signs of hypoglycemia? Did they just suffer a traumatic event and are in emotional overload? Are they non-verbal or neurodivergent?
We’ve had clients mistaken for drunk when they were in medical distress. And in some cases, officers made things worse by ignoring the signs.
Our job is to connect those dots for the judge or jury—to show that what might look like intoxication could easily be something else entirely.
10. The Dirty Stop—If It’s Illegal, It’s All Out the Window
If we can beat the stop, we beat the case.
Was the stop based on a made-up traffic violation? Did the officer misunderstand the law? Did they overreact because the driver didn’t pull over “fast enough”?
We’ve seen it all. Officers pulling guns on drivers who simply wanted a well-lit place to stop. Cops confusing legal behavior for suspicious behavior. We scrutinize the reason for the stop and ask: Was it justified?
If it wasn’t, everything that follows—including field sobriety tests—is inadmissible. And that’s our favorite kind of win.
Don’t Let a Test Decide Your Future—Call the Marc Lopez Law Firm
Field sobriety tests are not foolproof. They’re flawed, subjective, and often used incorrectly. At the Marc Lopez Law Firm, we know how to fight them, and we’ve been doing it successfully for years.
If you or someone you care about is facing DUI charges in Indiana, don’t roll over. At the Marc Lopez Law Firm, we’ll walk you through your options, break down your case, and start building your defense. Call 463-842-1724, and remember—always plead the 5th!
