Understanding Field Sobriety Tests
It starts with flashing lights in your rearview mirror and a sinking feeling in your stomach. You’re pulled over, and suddenly an officer is asking you to step out of the car. Maybe you’ve had a drink—or maybe you haven’t. But now you’re asked to perform a series of tests on the side of the road, and what happens next could change everything.
This is the moment where field sobriety tests come into play.
What These Tests Are Meant to Prove
Field sobriety tests are supposed to help officers decide if someone is under the influence of alcohol or drugs. They're meant to check physical coordination, balance, and mental focus. But what many people don’t realize is that these tests aren’t foolproof—and they’re not always fair.
The three main tests used are:
Horizontal Gaze Nystagmus (HGN): Following a pen or light with your eyes.
Walk and Turn: Walking heel-to-toe in a straight line, turning, and walking back.
One-Leg Stand: Standing on one foot while counting out loud.
They sound simple. But nerves, medical conditions, poor balance, or even bad shoes can trip up anyone—even if they’re sober.
The Real Problem: Subjectivity and Inaccuracy
Why These Tests Aren’t Always Reliable
Field sobriety tests aren’t scientific measurements. They're based on how you look to an officer during a stressful moment, often in the dark, on the side of a road, with cars whizzing by.
That makes them incredibly subjective. Officers are trained, but even well-trained people can misread the signs—especially when they're already looking for proof of impairment.
Things like age, weight, anxiety, injuries, or even uneven pavement can lead to false failures. And once an officer decides you "failed" a test, that decision can follow you into court.
The Numbers Don’t Lie
Studies show that many people who fail field sobriety tests aren’t actually impaired. High failure rates—even among sober drivers—make these tests more questionable than many assume.
False positives are common. So are mistakes made under pressure. This is a big reason DUI attorneys often challenge these tests in court. They know the science doesn’t always back the assumptions.
Your Rights and the Law
What the Law Says About These Tests
There are rules officers are supposed to follow when giving field sobriety tests. These come from the National Highway Traffic Safety Administration (NHTSA) and include strict instructions for how each test should be performed.
If those rules aren't followed exactly, the results may not hold up in court. Yet many officers make mistakes, skip steps, or give unclear directions.
Every state also has its own DUI laws. Some treat test refusal harshly, with automatic license suspensions. Others allow more legal wiggle room. That’s why it’s critical to know your rights and get legal help as early as possible.
Constitutional Issues You Should Know
Being asked to perform these tests on the roadside also touches on your constitutional rights.
The Fourth Amendment protects you from unreasonable searches.
The Fifth Amendment protects you from self-incrimination.
There’s often a legal debate around whether these tests count as evidence you’re providing against yourself—and what officers must prove before asking you to take them.
Knowing how these rights apply to your situation can make all the difference in your defense.
Breaking Down Field Sobriety Tests in Court
How Defense Attorneys Fight Back
One of the most effective strategies in a DUI defense is challenging how the field sobriety tests were administered. Lawyers often look at:
Whether the officer followed proper instructions.
Road and weather conditions.
Physical limitations or medical conditions.
The officer’s training and biases.
Video footage, witness accounts, and expert analysis all help show that what looked like "failing" might not be impairment at all.
Bringing in the Science
Attorneys sometimes bring in expert witnesses—people trained in medicine, forensics, or psychology—to explain why these tests aren’t as accurate as they appear.
These experts can cast doubt on the results, giving judges or juries a more realistic view of what happened. That kind of testimony can be key to reducing charges or getting them dismissed entirely.
Building a Strong DUI Defense
Collecting the Right Evidence
If you're facing DUI charges based on a field sobriety test, your defense starts with gathering everything:
Dashcam or bodycam footage
Medical records
Witness statements
Photos of the test location
Even small details can change how your performance is interpreted in court.
Looking at Past Case Wins
Many people don’t realize that courts have already ruled against improperly administered sobriety tests in the past. These legal precedents can help your case—especially when your attorney can show that your rights were violated or procedures weren't followed.
Protect Your Rights After a DUI Stop
You don’t have to face DUI charges alone. If you were arrested after performing a field sobriety test—or refused one—there may be defenses you haven’t even considered.
At Fife Luneau, P.C., we focus on defending people accused of crimes in California. Our legal team understands how field sobriety tests work, where they fall short, and how to challenge them in court.
Call (720) 408-7130 today for a free consultation. Let us help you fight back, protect your future, and take the next step toward clearing your name.