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What is a Breath Test in Los Angeles?

Los Angeles County law enforcement officers use breath tests both during DUI investigations and following DUI arrests to help determine if an individual was under the influence of alcohol while operating a vehicle.

A preliminary alcohol screening (PAS) is often conducted through a portable breath test.  A portable breathalyzer unit typically produces a rough estimate of the individual's level of intoxication. 

A post-arrest breath test generally requires an approved breathalyzer machine that has been subject to the calibration requirements of the state or federal government.  These machines are often located at a police station and typically produce more reliable results than the PAS devices.

If you were subjected to a breath test during a DUI investigation, or after you were arrested, and are facing DUI charges, contact Berglund Law Office, P.C. immediately at (877) 667-1205 or submit our CONTACT form.  

Can You Refuse a Breath Test in Los Angeles County?

You can refuse a breath test, but you should be ready to face the serious consequences that generally follow a refusal.  California's implied consent law requires a driver arrested on suspicion of DUI to submit to a chemical test.  If the driver is suspected of being under the influence of alcohol, he/she will typically be required to submit to either a breath or blood test.  

A driver who refuses to submit to the required chemical test is subject to a minimum one year driver's license suspension from DMV.  The suspension period will be longer if the driver has prior DUI convictions.  

Additionally, a breath test refusal can generally be used as evidence against an individual at trial.  The prosecutor will argue that the driver's refusal to submit to a breath test shows a "consciousness of guilt."  

Problems with the Breath Tests in Los Angeles

Unfortunately, the commonly used breath tests are not always an accurate representation of an individual's level of intoxication.  For that reason, it is important for an individual not to assume that they are guilty of a drunk driving offense simply because of the breath test results.

Many of the problems with breath tests relate to the testing device or machine, the individual operating the device or machine, or the test sample.  For instance, some of the common problems that could provide inaccurate results include:

  • Broken or untested device
  • Uncalibrated device
  • Testing performed by an untrained person
  • Failure to follow testing protocols
  • Improper instructions
  • Medical conditions suffered by the test taker
  • Medications, foods, or drinks

The results of a breath test can be challenged throughout a case, even prior to a trial to try to suppress any evidence due to problems with a breath test device or the results.

How an Attorney Can Challenge Breath Tests in Los Angeles County

A breath test is often a substantial part of the prosecution's case involving a DUI offense.  For that reason, it is essential to ensure that a breath test was performed correctly and the results are accurate.

A good Los Angeles DUI attorney understands the many potential problems with breath tests and the unreliability of their results.  It is important that an individual does not assume that the results of a breath test are accurate and unable to be contested simply because a law enforcement officer performed the test.  Breath tests can be challenged and should be challenged when appropriate.  Call us today at (877) 667-1205 or submit our CONTACT form to schedule a free consultation today.


Our office specializes in representing individuals facing traffic violations. We represent our clients in both court and at DMV hearings. Your case will be handled with the personalized attention and expertise that it deserves.

Free Consultation

There is no charge for the phone consultation. Our office specializes in representing individuals facing traffic violations. Attorney Robert D. Berglund will personally speak with you about your case and provide you with an honest analysis. Contact us today.