Preliminary Alcohol Screening Device in DUI Cases
What's the Difference Between a Preliminary Alcohol Screening Device, the Blood Test, and the Breath Test in a DUI? These are all tests designed to detect whether somebody's blood alcohol level is a .08 or greater.
First, when they stop someone at a traffic scene, the police ask many questions and may even perform a field sobriety test after talking to the person. A field sobriety test typically involves a series of physical and cognitive tasks to assess the person's level of impairment.
Before they make the trip to the police station, they often have the person blow into the Preliminary Alcohol Screening Device or PAS. This small device, carried in police vehicles, is the least accurate of the three tests, but it measures alcohol levels.
They were usually prevented from determining the result years ago. I've been doing this for 25 years, but now they can generally obtain that result.
The defense will often try to challenge the PAS result, but depending on the circumstances of the case, the judge may or may not admit it as evidence. This is usually done at the accident scene and is one of the least accurate of the three tests.
The breath test is the next test they will usually try to administer. That's generally in Los Angeles County done at the police station where they have you blow into a tube. It's attached to a machine that registers your blood alcohol.
They usually like to get at least two results so that their expert can try to show at a trial that your blood alcohol level was a .08 or greater and, hence, contact you for a DUI. This machine is called the Intoxilyzer 3000.
The next step is the breath test, administered at the police station. However, this machine, the Intoxilyzer 3000, has its challenges. Even the prosecutor's experts acknowledge its error rate of .02, meaning a .08 reading could potentially be a .06.
That's why a lot of times in Los Angeles County, the prosecutors will give something less than a DUI to resolve a case where the person blew a .08.
Of the three tests, this is probably the middle of the road as far as accuracy, but certainly something the prosecutors use every day to convict people for DUI cases.
These machines have to be calibrated, and sometimes, they have problems. That's another area to consider, especially if you suspect the device may have inaccurately registered your blood alcohol level.
I always ask my clients whether or not they've had anything to drink or how much they've had to drink. We find out their body weight, how much they've had to eat, and a host of other factors will be evaluated in deciding whether or not they've got the right blood alcohol level.
I've been doing it for 25 years, so once I can plug in where you're at, I can get a pretty good idea of whether there's some problem with either of the two breath tests.
Blood Test in DUI Cases
Lastly, there's the blood test. That's the most accurate test, and usually, if it's a close one—for example, the person blew a .08 or .09—we will do what's called a blood split, where we would test the blood ourselves with our expert to see if the police got it right.
This is a good strategy, especially in a close case or if you suspect some contamination in the blood. It is another way to challenge the prosecutor's key evidence to prove that the person was a .08 or greater. Blood splitting involves taking a portion of the blood sample and having it independently tested to verify the accuracy of the original test.
These three tests are used independently, and sometimes, they're all used together. It depends on how successful the police are in getting somebody's blood or breath results. Under California's implied consent law, if you don't give your blood or breath, you will be presumed to be DUI automatically. You'll also lose your license for a year with no restrictions.
They've got it set up pretty well, and these three tests are the primary evidence they use to prove DUI cases in Los Angeles County.
If these tests are used on you, whether individually or in combination, it's crucial to consult with a professional like me. I can assess their accuracy and guide you on the best course of action for your DUI case.
Hedding Law Firm is a criminal defense law firm located in the San Fernando Valley area of Los Angeles County at 16000 Ventura Blvd #1208 Encino, CA 91436.