When performing a DUI investigation, many officers will attempt to get you to perform what is called a Preliminary Alcohol Screening (PAS) test before you are arrested. Provided that you are over 21, and are not on probation for a previous DUI, any breath test before arrest is 100% voluntary. As a result, it is typically not in your best interest to perform a PAS test.
After Arrest: Breath or Blood
The focus of this guide is not whether or not you should answer the officer's questions about how much you've had to drink or whether or not you should perform Field Sobriety Tests. However, keep in mind that you are not obligated to answer any such questions by the officer, and are also not obligated to do any of the Field Sobriety Tests. Generally speaking, it is almost always best to give the officer the least amount of evidence that you can, and therefore, you should politely decline to answer any questions or do any balancing tricks.
The issue here, rather, is, once you have been arrested, should you do a breath or blood test. Keep in mind that in California, the implied consent law requires you to give either a breath test or a blood test. Many people believe that a blood test is the best option, presumably because the sample can be retested. However, there are additional factors that should be a part of you decision as to which test to perform.
Your Alcohol Level: Is It Rising or Falling?
When you drink, your blood alcohol concentration (BAC) rises while you continue to drink, and continues to rise for a short period after you have stopped. The average time for a person's BAC to peak ranges from 15 minutes to about an hour. Once you peak, your BAC will begin to fall as your body continues to eliminate the alcohol from your system.
The breath test will almost always be performed significantly quicker than the blood test. In Ventura, it usually takes about an hour to get the blood test done, while the breath test will often be completed within about 15 minutes.
As a result, one factor to consider is how much time has elapsed since you stopped drinking. If you drank very recently before driving, it might be best to do the breath test before all of the alcohol is absorbed into your system. If it has been a long time since your last drink, you might want to choose the blood test, as your BAC should continue to fall before your blood can be drawn.
Accuracy of The Tests
Another factor that should be considered when choosing breath or blood is the accuracy of each test. Generally speaking, it is much more difficult to attack a blood test than a breath test. Of course there are exceptions to this rule, and it is typically a good idea to have your blood retested.
On the other hand, a breath test result can be attacked from a number of different angles. First, the officer must be qualified to use the breath machine, and must use it correctly. Second, the breath machines must be tested for accuracy every 10 days or every 150 tests, whichever comes first. Because only a few officers from each agency are qualified to perform the accuracy tests, these requirements are sometimes not met due to an officer's vacation schedule or some other unknown and unforeseen event. Additionally, there are a number of factors that can give a falsely high reading on a breath test, such as mouth alcohol, that simply do not effect the results of a blood test.
Breath or Blood: Which One Should You Choose?
First, the best way to avoid having to make such a choice is to not drive after drinking. However, because drinking and driving is generally legal (as long as you are over 21 and not on probation for a DUI and are not impaired and/ or above a .08), many people will continue to be faced with just such a choice.
As you can see from the brief explanation above, there are a number of factors that you should consider when choosing breath or blood.