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Breath Evidence

When reviewing and evaluating a client's case, DUI defense attorneys in Los Angeles will typically find that the criminal case and the administrative DMV case are predicated upon the results of a breath test. Because the administration of a breath test is far less invasive than submitting to a blood test, most of our citizens opt for breath analysis during a DUI investigation.

Many of the most renowned experts in the field concur that breath analysis is inherently unreliable. The formulas used in converting exhaled air into represent the amount of alcohol in a person's blood make certain assumptions that lump all people into an "average" category. Because of the vast differences in each person's physiological make-up, basing a scientific reading upon such an "average" is ludicrous.

Current studies reveal that breath readings can differ from actual blood alcohol readings by as much as 15 percent. Also, toxicology studies have revealed that 23 percent of all individuals tested by breath analysis will have results higher than their true blood alcohol levels. In short, this is just bad science.

When a subject is in the absorptive stage (a period of 20-30 minutes after they stop drinking), a breath device will vastly overstate the true alcohol level. Therefore, if a person is stopped shortly after drinking and they blow into an unreliable PAS device minutes later, the device will often exaggerate the true alcohol level and a police officer will base an arrest on the reading, not the actual performance of field sobriety tests. This means that a person could perform all field sobriety tests with pin-point and exact accuracy but be arrested if a breath device declares the alcohol level to be .08 or greater.

Breath analysis is most often broken down into two categories:

  • Preliminary Alcohol Screening
  • Evidentiary Breath Analysis

Preliminary Alcohol Screen (PAS)
Most commonly known as the PAS test, the Preliminary Alcohol Screening test is usually administered to a suspected drunk driver at the scene of a traffic stop, in the back of an ambulance, or often while the driver is being treated at a hospital. These tend to be small, hand-held, devices that are carried by on- duty patrol officers in their patrol vehicles. These devices are normally lightweight and made of durable plastic. It is not uncommon for these machines to be tossed in the trunk of police vehicles or to be dropped on the ground.

Breath analysis originated in the 1970's as a balloon that simply turned a certain color if alcohol was present. Today, the technology employed in the PAS device is far more sophisticated than those early machines, however, they remain primitive and unreliable.
With a few exceptions, our citizens are not required to submit to a Preliminary Alcohol Test during the course of a DUI investigation. A PAS test is generally considered to be another form of a field sobriety test, however, many judges are now allowing the results of a PAS test as evidence of the defendant's blood alcohol concentration at trial. Notwithstanding the exceptions listed below, blowing into a PAS device is just you creating incriminating evidence against you.

The Preliminary Alcohol Screening device has become a favorite tool among nearly every California Law Enforcement Agency, including the California Highway Patrol. Theoretically, the PAS should carry no more weight than any other Field Sobriety Test, however in actual practice, officers are trained to blindly trust the accuracy of these hand-held devices and will make an arrest based on their readings even if you perform all other tests perfectly.

California Vehicle Code section 23612 mandates that a driver shall submit to a chemical test of their blood or breath, "if lawfully arrested." Essentially, this means that you are not required to give any blood or breath testing (in any form), unless you have been arrested.

You must submit to a PAS test prior to arrest if:

  • You are under the age of 21 at the time of the investigation.
  • You are on probation for a prior DUI conviction.

Barring these two exceptions, our citizens are not required to assist police officers in collecting potentially damaging evidence against them. Why would you?

Evidentiary Breath Analysis
The most common form of scientific evidence utilized in DUI cases today are air samples captured by an evidential breath device. Constructed with more safeguards than the standard PAS device, evidential breath machines are thought to be more reliable. The basic science surrounding these devices, however, is the same as used in the PAS device. The evidential breath machine "assumes" certain averages for every person who blows into it and therefore this device is just as untrustworthy as the PAS device.

Some of the most successful DUI defense experts in the country have attacked the accuracy and reliability of the evidential breath device for many years. Scientists have conducted exhaustive studies and extensive treatises have been written which clearly document the pseudoscience behind this form of alcohol analysis. In their zeal to protect the motoring public however, State and Federal government and courts have ignored the basic fundamentals of law, science, and mathematics by blindly accepting the accuracy of breath devices and allowing prosecutors and DMV hearing officers to blindly assume their reliability, despite the arguments of common sense.

Fortunately, there are some basic requirements that must be established before an evidential breath sample may be presumed accurate:

  • The breath device must be on a conforming list of acceptable devices.
  • The breath device must be properly maintained and checked for accuracy every 10 days or 120 tests.
  • The person administering the test must be certified in the use of that particular device.
  • The person administering the test must do so in accordance with his training.
  • The person administering the test must ensure the test subject does not burp, regurgitate, eat, vomit or smoke for a period of 15 minutes immediately prior to the testing sequence.
  • The breath test must capture at least two measurable readings that are within .02 of one another.

The Los Angeles DUI experts on our staff are some of the most versed and experienced lawyers in the field of DUI defense. The knowledge of breath testing and the methods used to successfully attack its accuracy is in the bedrock of their DUI defense law firm.