The 15 Minute Observation Period Before a Breath Test


Title 17 of the California Code of Regulations sets forth the procedures law enforcement must follow to ensure the accuracy of chemical tests during a California DUI investigation. One of the procedures that officers must follow is the “15 minute continuous observation period” before conducting a breath test on a DUI suspect.

Breathalyzers collect air from deep within the lungs which is called “alveolar air.” As the alveolar air is collected by the breathalyzer, it passes through the esophagus and mouth. However, if a person eats, drinks, smokes, burps, vomits, or regurgitates prior to the breath test, it is possible that the alveolar air produces an exaggerated blood alcohol content reading.

The observation period is to ensure that the DUI suspect does not do any of these things.

Often is the case, however, that officers don’t observe the DUI suspect such that they would be aware that any of these things happened. While the officer may indicate on his police report that he observed the suspect, his “observation” may have included actions which would make the “observation” anything but continuous.

During the observation period, the officer may walk back to his squad car, check a license, talk to a partner, prepare the breathalyer machine, or write up their report or citation.

 

Whatever the case may be, their attention is often diverted even if only for a short while. But a short while is all it takes for a DUI suspect to belch. And a belch is all it takes to lead to a falsely elevated BAC reading.

The 15 Minute Observation Period Before a Breath Test

Title 17 of the California Code of Regulations sets forth the procedures law enforcement must follow to ensure the accuracy of chemical tests during a California DUI investigation. One of the procedures that officers must follow is the “15 minute continuous observation period” before conducting a breath test on a DUI suspect.

Breathalyzers collect air from deep within the lungs which is called “alveolar air.” As the alveolar air is collected by the breathalyzer, it passes through the esophagus and mouth. However, if a person eats, drinks, smokes, burps, vomits, or regurgitates prior to the breath test, it is possible that the alveolar air produces an exaggerated blood alcohol content reading.

The observation period is to ensure that the DUI suspect does not do any of these things.

Often is the case, however, that officers don’t observe the DUI suspect such that they would be aware that any of these things happened. While the officer may indicate on his police report that he observed the suspect, his “observation” may have included actions which would make the “observation” anything but continuous.

During the observation period, the officer may walk back to his squad car, check a license, talk to a partner, prepare the breathalyer machine, or write up their report or citation.

Whatever the case may be, their attention is often diverted even if only for a short while. But a short while is all it takes for a DUI suspect to belch. And a belch is all it takes to lead to a falsely elevated BAC reading.

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