In California, almost all DUIs are charged under one of two laws: Vehicle Code 23152(a), which says you were clearly impaired by alcohol or drugs, or 23152(b), which says that you had a blood alcohol concentration (BAC) of .08% or higher while driving. Of these, 23152(b) is the most common, and the most common way of testing your BAC is using a breath test device, such as a PAS.
The results of your breath test can seem definitive—after all, they “prove” how much alcohol was in your system. But they aren’t always right. The equipment itself can be inaccurate, the officers giving you the test can make mistakes, and there are many reasons why you would get a false positive that “proves” you were over the limit even though you weren’t.
A good DUI lawyer will never take the PAS breath test results at face value. Attacking the validity of the test results can be a powerful way to defend your DUI case. It could mean getting a key piece of evidence against you tossed out of the case. It could even mean getting the charges against you dropped.
What is the difference between a PAS and other breath tests?
PAS stands for Preliminary Alcohol Screening, and it’s used during traffic stops while investigating a potential DUI. The PAS uses a small portable breath test device that officers can use with minimal training. It’s typically done before the arrest, often within minutes of pulling you over. Officers will use the results of the PAS to consider whether to arrest you for DUI or not.
But PAS tests are notoriously unreliable. Unlike the breath test machines used in police precincts and crime labs, they have a wide margin of error from one sample to another. Similarly, they’re susceptible to being tricked by traces of alcohol still in the mouth. While other breath test machines have a “slope detector” which helps screen out this trace alcohol, most portable PAS systems do not.
It’s possible to challenge the breath test results no matter what device was used. But if you were tested on the side of the road before or during your initial arrest, the device was likely a PAS and is particularly open to challenge.
Why is the breath test result such a big deal?
Technically, prosecutors can seek a DUI conviction with or without a breath test. But it’s much easier to convict you if they have a test showing that your BAC was above the legal limit, or .08% in most cases. If they don’t have this key evidence (or another similar test, like a blood test) then they have to prove that you were physically or mentally impaired by whatever alcohol you consumed. In some cases, they need to prove that you were drinking at all.
This is why the test results matter so much. Whether or not the prosecutor has breath test evidence can be the difference between convicting you and letting you go.
What if I really was drinking? Can I still fight the breath test?
Yes. It’s rare that a driver arrested for DUI was stone sober, although it does happen. In many cases, however, the driver did have some drinks—but maybe not enough to be a danger to other people. The “legal limit” of .08% BAC isn’t easy to hit. A grown man might need three or more drinks to exceed it, while a woman might need two or more. If you are drinking slowly over time, or on a full stomach, you could potentially have even more drinks and still be legal to drive.
In a DUI case, you don’t have to prove you didn’t drink at all. You just need to prove that your BAC was not .08% or higher, at least not while you were driving. And, technically, you don’t even have to prove that; you just have to cast doubt on whether you were over .08% or not.
Many DUI defendants win their cases even though they were drinking and the test said a number higher than .08%. A win can mean winning in court, getting the charges dropped with no trial, or simply getting the charge reduced to something less severe than DUI. The goal is to help you keep your license, avoid jail time, and make your DUI as inexpensive as possible.
What are the best strategies for attacking the breath test results?
Strategies can include:
- The Mouth Alcohol Defense: If you had some source of alcohol in your mouth, such as mouthwash or breath spray, the test results may be wrong. The same goes if you sipped alcohol just moments before the test, or if you took medicine with alcohol in it.
- The Diabetes/Low Carb Diet Defense: Sometimes your body chemistry can cause you to fail a breath test even if you’re not over the legal limit. This can be true for both diabetics and anyone eating a very low carb diet.
- GERD / Acid Reflux Defense: Similar to mouth alcohol, if you have GERD or acid reflux, then alcohol from your stomach can be regurgitated into your mouth and throw off the breath test. Officers are supposed to observe you for 15 minutes before a breath test to make sure you do not vomit, belch, or eat or drink anything.
- Rising BAC: If there was a long delay between when you were first pulled over and when you were tested, your BAC may have gone up during the extra time. This means it was lower when you were actually behind the wheel.
- Blood-Breath Partition Ratio: Breath tests have to calculate your blood alcohol using only your breath alcohol. To do this, they assume a certain ratio: 1 to 2100 between the amount of alcohol in your breath versus the amount in your blood. This is the “average” number, but most people are not average. This allows you to call the breath results into question.
- Improper Calibration: By law, breath test devices must be calibrated every 10 days or 150 uses, whichever comes first. Records are kept of these calibrations. If the device used in your test wasn’t calibrated according to schedule, the results may not count.
It is also possible to defend against the claim that you refused the breath test.
Have you been charged with DUI? We can connect you with an experienced Los Angeles DUI lawyer and get you a FREE consultation. Fill out the form to the right or call (310) 862-0199 and get your free consultation today.