You see the lights in your rearview mirror, you pull over, and within a few minutes, the officer is asking you to step out of the car. What happens next is where many DUI cases are won or lost, yet most people have no idea what they’re actually required to do versus what they’re simply being asked to do. Those are two very different things.
We’ve handled thousands of DUI cases in Pennsylvania, first as prosecutors building these cases and now as defense attorneys challenging them. Understanding your rights during a traffic stop, before you ever blow into a breathalyzer or attempt a field sobriety test, is one of the most valuable things you can know. Here’s what you need to understand about field sobriety tests in Pennsylvania.
What Is a Field Sobriety Test?
A field sobriety test is a series of physical and cognitive exercises a police officer may ask you to perform roadside when they suspect you’re driving under the influence. The officer is watching how you move, follow instructions, and respond under pressure. In reality, they’re gathering evidence, and everything you do during these tests can end up in a police report and eventually in front of a jury.
There are three tests standardized by the National Highway Traffic Safety Administration (NHTSA) that are most commonly used in Pennsylvania:
- Horizontal Gaze Nystagmus (HGN)
- Walk-and-Turn
- One-Leg Stand
Officers are trained to administer these tests using specific procedures. When those procedures are not followed correctly, it may create opportunities for a defense attorney to challenge the results.
Beyond the standardized tests, officers sometimes ask drivers to perform non-standardized exercises such as reciting the alphabet, counting backward, or touching a finger to their nose. These tests generally carry less scientific support and are often even more subjective in how they are evaluated.
Are You Required to Take a Field Sobriety Test in Pennsylvania?
No. In Pennsylvania, field sobriety tests are voluntary. You are not legally required to perform them, and refusing is not a criminal offense.
That said, an officer can note your refusal in their report, and depending on the circumstances, it may become part of the overall case. There is no one-size-fits-all answer, but it is important to understand that agreeing to perform the tests often gives the officer additional evidence to use against you.
Field sobriety tests are designed to identify signs of impairment, not necessarily to clear someone of suspicion. Many drivers who agree to perform the tests later wish they had not. That does not mean declining is always the right decision, but it does mean you should understand what you’re giving the officer when you agree to participate.
If you choose to decline, do so politely and respectfully. There is no need to argue or explain your reasoning. Staying calm and cooperative is usually the best approach.
It’s also important to understand that refusing a field sobriety test is very different from refusing a chemical test. The legal consequences are not the same, and confusing the two is one of the most common mistakes people make during a DUI stop.
What the Officer Is Actually Looking For
During the HGN test, an officer watches your eyes for an involuntary jerking movement called nystagmus. Alcohol can exaggerate this movement, but so can fatigue, certain medications, anxiety, lighting conditions, and other factors unrelated to alcohol consumption.
The Walk-and-Turn and One-Leg Stand tests are known as divided-attention tests. They are designed to evaluate whether a person can follow instructions while performing a physical task. Officers are trained to look for specific clues and score the tests accordingly.
Roadside conditions can have a significant impact on performance. Uneven pavement, gravel, poor lighting, traffic noise, weather conditions, injuries, age, balance issues, and even footwear can affect the outcome of these tests.
As former prosecutors, we understand how officers are trained to score these exercises and how those observations are presented in court. We also know how to challenge them. The tests must be administered correctly, the conditions must be reasonable, and the officer’s observations must be credible. When those factors break down, the reliability of the test results can be questioned as well.
Chemical Tests: These Are Different
This is where the rules change significantly.
Pennsylvania has an implied consent law. By driving on Pennsylvania roads, you have already agreed to submit to a chemical test, such as a breath, blood, or urine test, if you are lawfully arrested for DUI. Unlike field sobriety tests, refusing a chemical test can carry serious consequences.
One important fact many drivers don’t know is that anything other than a clear and unequivocal “yes” can be treated as a refusal. Asking questions, delaying your answer, or requesting an attorney before deciding may be interpreted as a refusal under Pennsylvania law.
If you refuse a chemical test after a lawful DUI arrest, PennDOT can suspend your driver’s license for 12 months for a first refusal, even if you are never convicted of DUI. A second refusal within 10 years can result in an 18-month suspension.
It’s also important to understand the difference between a formal chemical test and a roadside portable breath test (PBT). In many Pennsylvania counties, the formal chemical test is a blood draw performed after arrest. Some counties, such as Lancaster County, use certified breath-testing equipment at the police station.
The roadside PBT is a separate tool used during the investigation phase. Refusing a roadside PBT does not trigger the same license suspension consequences as refusing the formal chemical test administered after arrest.
Whether to submit to a chemical test depends heavily on the specific facts of your case. However, drivers should understand that the decision often must be made quickly, and hesitation itself can sometimes be treated as a refusal.
What to Do If You’re Pulled Over
The first few minutes of a DUI stop matter more than most people realize. Officers are trained observers, and everything from how you pull over to how you speak and provide documents may become part of their report.
Remaining calm and composed is not just good advice. It can also help protect your interests.
A Few Things to Keep in Mind
- Pull over safely and promptly.
- Turn off the engine and keep your hands visible.
- Provide your license, registration, and proof of insurance when requested.
- You are not required to answer questions about where you’ve been, where you’re going, or whether you’ve been drinking.
- If you decline field sobriety tests, do so politely and respectfully.
- Do not argue, resist, or make the situation confrontational.
None of these steps guarantee that you won’t be arrested. However, they may help limit the amount of evidence gathered against you before an attorney has the opportunity to review your case.
If You’ve Already Been Arrested for DUI
If you’ve already been arrested, don’t assume your case is hopeless because you performed field sobriety tests or because a chemical test showed a result above the legal limit.
DUI cases involve far more than a single test result. The legality of the traffic stop, whether the officer had probable cause to arrest, how testing was administered, whether equipment was properly maintained and calibrated, and whether your rights were respected throughout the process are all issues that may affect the outcome of a case.
We’ve had clients come to us believing their case was open and shut, only to discover significant problems with the stop, testing procedures, or evidence collection. Every case deserves a careful review.
If you’ve been charged with DUI, speak with an experienced attorney as soon as possible. The sooner your case is evaluated, the sooner potential defenses can be identified and preserved.
