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Breathalyzers and DUI Arrests in California

If you are suspected of drunk driving in South Lake Tahoe, or elsewhere in California, you may be asked to provide a chemical sample, which could take the form of a breath, blood, or, in rare circumstances, a urine test. As a lawyer who has represented hundreds of people charged with DUI, I’ve seen how misconceptions about these tests and your right to refuse them can lead to problems with your driver’s license and criminal charges. For inquiries or to consult with a criminal defense attorney with experience representing people arrested for driving under the Influence please call or text (530) 208-0911 for a free consultation.

Understanding Different “Breath Tests”

Police use breath tests to determine if suspected drunk drivers were intoxicated or “impaired” while driving. There are two main types: preliminary alcohol screening tests (PAS) and evidentiary breathalyzers, both are often referred to as "breath tests." However, they serve different purposes.


Preliminary Alcohol Screening (PAS) Tests

Preliminary Alcohol Screening or “PAS” devices are portable breath alcohol testing devices used during traffic stops or DUI investigations. They are the handheld devices commonly depicted in movies and media that display a numerical value after someone has blown into them. Police administer PAS tests when they suspect someone of driving under the influence. Police officers will typically testify that they rely on the PAS device results, along with other symptoms of intoxication like slurred speech or bloodshot eyes, in deciding to arrest someone for driving under the influence.


Evidentiary Breathalyzers

After a DUI arrest, police will inform a suspect that they are required to submit to an evidentiary chemical test. If police suspect that the arrestee has only been drinking, and other drugs are not involved in their impairment, they will typically give them the option to choose between a blood test or a breath test. If the arresting officer suspects the arrestee may be under the influence of a drug, they may require them to submit to a blood test and not give you the option to submit to a breath test because a breath test will not detect the presence of other drugs in your body. Evidentiary breathalyzers are not portable and are typically kept at a police station or jail. They provide a printed receipt-like record of tests performed.


Mandatory versus optional tests

The most significant distinction between the preliminary alcohol screening test and the evidentiary breathalyzer is your obligation to take them and their potential evidentiary value. You may refuse the preliminary alcohol screening test without a specific penalty to your driver's license or criminal case. Conversely, refusing to take the chemical test, either evidentiary breathalyzer, or blood, will result in a mandatory suspension of your driver's license. This is because when you receive a driver's license in California, and most other states, you sign an advanced consent agreement or “implied consent” that essentially says you agree in advance to submit to a chemical test if you are arrested for driving under the influence, and you acknowledge that the consequences for refusing such a test would be a suspension of your driver's license.


The result of an evidentiary breathalyzer will almost certainly be admitted at a trial against you should you be charged with driving under the influence. However, there are certain procedural safeguards intended to ensure law enforcement follows best practices when administering both of these tests. An attorney with experience litigating these types of cases will know these requirements. They include ensuring there was an adequate observation period before the tests were administered, where the subject did not burp, or consume any food or liquids, and also requirements regarding the proximity of test results. These are just more good reasons to make sure you have an experienced criminal defense attorney representing you, so they can determine if these procedures were followed. Furthermore, evidentiary breast tests, administered at police stations and jails are typically much more accurate than the ones administered on the side of the road that are carried around in a police officer’s trunk.


While you might be tempted to think that it's almost always a good idea to exercise your right to refuse a preliminary alcohol screening test if requested to take one, it is potentially possible that the district attorney might seek a "consciousness of guilt" instruction, or at a minimum argue to the jury that you declined to take the test because you knew or suspected that you would be above the legal limit and you wanted to delay the process to "sober up." A skilled attorney will be able to make arguments contrary to this position, but it will ultimately be left to the judge's discretion if the district attorney is able to make those arguments.


Common Breath Test Problems

Breath tests, especially portable ones, are known for their unreliability. Problems can arise from the device, administration, or test sample. An attorney can challenge breath test results in several ways:

  • Questioning reliability due to faulty machines, improper administration, or health issues.

  • Demonstrating improper calibration.

  • Proving inadequate device maintenance.

  • Highlighting a lack of officer training.

  • Pointing out improper record-keeping.

  • Arguing that the required observation period prior to the test was not complied with.

  • Identifying that the range between breath results is indicative of an inaccurate test.

Whether you took a breath test or refused one, you can challenge DUI charges. A skilled DUI defense attorney in South Lake Tahoe with experience litigating DUI cases will put you in the best position to identify and challenge any issues regarding these tests. Contact Kyle Neddenriep today, and together we’ll assess your case and discuss your legal options.

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