Field Sobriety Tests vs. Breathalyzers — Can You Refuse?

If you’re pulled over on suspicion of drunk driving in Los Angeles, the officer may ask you to perform a series of roadside tests or blow into a handheld breath device. These tests — field sobriety tests and breathalyzers — are used to determine whether there’s probable cause to arrest you for DUI. But many drivers wonder: Can I refuse? Will it help or hurt my case if I say no?

Understanding your rights and the differences between these types of tests is crucial if you find yourself in this situation. In California, the rules around refusal depend on what kind of test is being requested and when in the investigation that request occurs. Learn more below about the different types of drunk driving tests LAPD officers frequently employ. If you or a family member has been arrested for driving under the influence in LA, contact the Kosnett Law Firm for immediate assistance from a skilled and experienced Los Angeles DUI defense lawyer.

Field Sobriety Tests

Let’s start with field sobriety tests, which are the coordination and balance exercises officers often use during a DUI stop. These tests include things like walking in a straight line, standing on one leg, or following a moving object with your eyes. While police officers might make it seem like these tests are official requirements, field sobriety tests are actually voluntary in California. You are not legally required to perform them, and there is no penalty for politely declining.

Many drivers agree to take these tests without realizing that the interpretation of test results is highly subjective. Officers may take nervousness, fatigue, or natural coordination issues as signs of impairment. The truth is that even sober individuals can struggle with these tasks, especially at night, on uneven pavement, or under stress. The purpose of these tests, however, is not to determine whether you are inebriated, but to give officers the justification they need to place you under arrest and force you to take a chemical breath test, which is mandatory whether you want to or not.

By refusing to perform field sobriety tests, you deny the officer potentially incriminating observations, and you don’t give the prosecution more ammunition to use against you later. However, prosecutors can and do use your test refusal against you in court if you end up being arrested and charged, implying to a jury that you refused the test because you knew you were intoxicated. Still, an experienced defense attorney can counter this argument in many ways.

Preliminary Alcohol Screens

Another test officers may ask you to perform is the Preliminary Alcohol Screening (PAS) test. This is a handheld breathalyzer device used at the scene, typically before an arrest has been made. The PAS is commonly used in combination with field sobriety tests to help the officer determine whether there is probable cause to arrest a driver for DUI. Bear in mind that a PAS device, like the Alco-Sensor IV, is not the same type of device that is used to conduct a post-arrest breath test. It is less sophisticated, less accurate and less reliable.

So, can you refuse the PAS test? It depends on your age and your driving status.
If you are over 21 and not on DUI probation, the PAS test is considered voluntary, just like the field sobriety tests. You can lawfully refuse to take it without automatic penalties. However, if you are under 21 or on probation for a prior DUI, refusing the PAS test will violate California’s “zero tolerance” and probation laws, leading to automatic license suspension and other consequences.

Chemical Tests

If you are arrested, the situation changes. At that point, California’s implied consent law kicks in. Once you’re taken into custody on suspicion of DUI, you are required to submit to a formal chemical test, which may be either a breath or blood test at your option, at the police station or medical facility. This breathalyzer machine is different from the roadside PAS. Refusing this post-arrest chemical test carries serious consequences.

If you refuse a chemical test after arrest, the DMV will automatically suspend your driver’s license for at least one year, even if you’re ultimately not convicted of DUI. The refusal can also be used against you in court as evidence of guilt. Additionally, you may face increased penalties if you’re later convicted, including mandatory jail time and longer license suspensions.

There is often confusion between the PAS breath test and the post-arrest breathalyzer. Officers don’t always clearly explain the difference, and many drivers are caught off guard. To protect yourself, it’s important to remember this basic breakdown:

• Field Sobriety Tests (Pre-Arrest): Voluntary. You may politely decline.
• PAS Test (Pre-Arrest Breath Test): Voluntary if you’re over 21 and not on DUI probation. Mandatory if you’re under 21 or on probation.
• Post-Arrest Chemical Test (Breath or Blood): Mandatory. Refusing leads to automatic penalties.

How to Treat a Roadside DUI Stop

If you’ve been pulled over, it’s usually best to remain calm and respectful. Politely decline field sobriety tests and, if applicable, the PAS test, but don’t argue or resist. Remember, you do not have to explain yourself or provide details about where you were or whether you’ve been drinking. Simply exercising your right to remain silent can make a big difference in your defense. If police continue to question you, clearly state that you wish to speak with an attorney before answering any further questions.

If you were arrested for DUI in Los Angeles after refusing a test or struggling through field sobriety exercises, it’s vital to consult with a skilled DUI defense lawyer right away. At the Kosnett Law Firm, we know how to challenge questionable police procedures, expose flawed test results, and protect your rights at every stage of the process. We’ll look at the facts of your case, including whether the officer had probable cause, whether the tests were administered properly, and whether your constitutional rights were respected.

Even if you refused a test, that does not mean you will automatically be convicted. In some cases, a refusal can actually make the prosecution’s case weaker, depending on what other evidence they have. Your defense strategy will depend on the full circumstances of your arrest.

Arrested for DUI in LA? Contact the Kosnett Law Firm Today!

Facing a DUI charge may feel intimidating or even overwhelming, but you don’t have to face it alone. If you’ve been arrested for DUI in Los Angeles, contact Kosnett Law Firm today. We can help you understand your rights, fight back against the charges, and work toward the best possible outcome in your case.