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The DUI Guys

Are The Breathalyzer & Field Sobriety Tests Admissible In Court?


Preliminary Alcohol Screening (PAS) tests are actually defined as field sobriety tests and are referenced in the California Vehicle Code under section 23612. The law authorizing their use during a DUI investigation requires the officer who seeks to use one on a driver give a specific advice. The officer is required to inform the subject that this breath test is not their implied consent test. This is because the PAS test is not an evidential test. It is just a tool to assist the officer in deciding whether or not to arrest you. It is a handheld, portable device that can give an estimate of your blood alcohol concentration. When you get your license, you agree that if you are arrested for a DUI, you will submit to a blood or breath test (and in certain instances, urine test). And if you refuse, then there are sanctions.

The PAS roadside test is not the same as the post-arrest evidential test you agree to submit to when you get your driver’s license. So the officers are supposed to make clear that the PAS breath test on the side of the road is not your “obligation” test, the PAS is a voluntary test and you have the right to refuse to take that test, without any consequence to you (unless you are under 21 years of age or currently on probation for a prior DUI case, in which case you are required to submit because you are young or as a condition of probation). Many times, officers will say “voluntary,” but they fail to tell you “YOU CAN REFUSE THIS TEST” which is what the law actually requires of them. You have an absolute right to refuse to take that test. Could you refuse? Absolutely.

However, if they get a result from you on the PAS, the officer will use that reading as part of their justification of their decision to arrest. Furthermore, the prosecution will seek to use the results in court. So you definitely want to refuse it but the reason you want to refuse it is, a) the government is going to use the results to justify a decision to arrest; and b) to prosecute you in court. The actual admonition they give you (even if they do it correctly) is a lie, because the information from the PAS will be used not only by the officer to justify arresting you (and requiring that you submit to another test for the actual alcohol content of your blood or breath, or drug content of your blood or urine), but, also by the prosecutor to prosecute you.

There are means of attacking the results and keeping them from being used in court. It used to be that PAS results weren’t so admissible. It was more of an uphill battle for the prosecutor to get them into evidence, but agencies have gotten savvy towards that, and at the same time, judges have gotten relaxed about admitting the results in evidence. Although it doesn’t come into prove the per se count, (the 0.08 or the 0.04 for a commercial driver), it can come in as evidence. The jury gets to hear about it, and you have to fight than to try to show that the police can’t really rely on that because that’s a preliminary test and not an evidential test.

The PAS devices are not maintained by the crime lab, just the law enforcement agency. There are a lot of problems with them—they can over-estimate your actual blood alcohol concentration; there are different substances that can add to the result or create an erroneous positive result, reading as alcohol—but you don’t want to be in a position of having to make all those excuses and trying to persuade somebody not to believe a number, because people are simple and a number is simple.

Explaining to them the scientific reasons why they shouldn’t rely on that number is hard. You want to make it easy for a jury to acquit you, or hard for the prosecutor to convict you. Don’t give them numbers, don’t do the PAS test, respectfully decline as you are given a right to do so and you should do.

Unfortunately, if you are under 21, you cannot say no. Likewise, if you are on probation for a DUI or alcohol related driving offense, one of the conditions of your probation is that you submit to a PAS test. You can’t say no. In both of those instances, if you refuse, you can lose your license for a year and you cannot get a restricted license if that happens. This is so, even if you, in fact, have zero alcohol in your system. So if you’re on DUI probation or under 21, you’d best submit to the PAS test.

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How Accurate Are Evidential Breathalyzer Results In DUI Cases?

They can be quite accurate. Or, not.

The problem is breath testing contemplates a number of variables that scientifically affect the legitimacy or validity or accuracy of the result. But in court, the legislature has made it easy for the prosecution and hard for the defense by preventing a jury from learning about many of those variables. Our Supreme Court has said essentially, the Legislature wrote the law to help prosecutors by removing scientific knowledge from the law and we will support that effort by preventing defendants from seeking to educate jurors, which would make it harder for prosecutors to be successful in getting convictions, therefore, defendants may not present evidence that would show the limitations of breath testing.

It is much easier for the prosecution when they don’t have to deal with the evidence that a stated Breath Alcohol Test (BrAC) may or may not be reflective of somebody’s blood alcohol concentration, may or may not be an accurate test, may or may not be within an acceptable range. Breath testing can work—if the conditions are right, and the officer is diligent, the device is rigorously tested and properly maintained and the test subject fits within the parameters of “the average person” rather than being towards one end or the other of the spectrum of the human condition, is cooperative and does everything they’re supposed to do, correctly.

There can be a number of things that get screwed up in that because everybody is different. The way that alcohol comes out in our breath can be different within each individual at different times. It can be different between individuals. It can depend on whether or not you are in the absorptive phase, meaning you’ve got alcohol in your stomach that is still being absorbed into your blood and distributed through your body, or if you’re in the post-absorptive state meaning you’ve absorbed all the alcohol that you’ve consumed and now your body is just in the process of metabolizing it. From a scientific standpoint, what is acceptable is a margin of 0.02 between two tests and under the law that will be considered a valid test. For some people, that is the difference of one drink, meaning two tests with the variation of a complete drink, taken two or three minutes apart is considered legally valid. In a .08% BAC case, that is a 25% margin of error: A pretty loose standard for determining whether someone is a “criminal” or not.

You could have a test of 0.06 and a 0.08, and that may be the lawful test. In that case, you’ve got evidence pointing to your innocence, and that would be beneficial. A prosecutor could still prove that you were driving with 0.08 at the time of your driving, depending on your answers to questions and information provided to the arresting officer during your stip. This is another reason why you shouldn’t be answering questions, which may incorrectly suggest you were fully absorbed at the time you were driving—that the delay between the time of driving and the time of the test would suggest that your blood alcohol concentration was higher at the time of driving. They would point to that 0.08 test and try to persuade the jury that you were in fact at 0.08 or above, at the time of driving and to disregard that 0.06% result.

But the fact that there is that much difference between two tests and the law would consider that valid in the face of science that would show that that’s at least one drink or more than an hour’s worth of metabolic elimination (or burn-off). That’s a huge variation, but it would still be legally considered acceptable.

These are some of the problems with breath testing, but there are multiple other issues why breath testing is problematic. Unfortunately, we go back to the problem that people just are not that bright and a number is really simple and science is really hard. So, without a skilled guide to educate and persuade them, they will tend to just accept the number, rather than consider the problems associated with that number. This is why having a knowledgeable attorney, skilled in the complexity of DUI defense is so critical.

For more information on Breathalyzer & Field Sobriety Tests, a free initial consultation is your next best step. Get the information and legal answers you are seeking by calling (619) 817-8332 today.

The DUI Guys

Call For A Free Case Evaluation
(619) 817-8332

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