15 Minute Observation in Breath Test Cases
The reliability of breath test results in DUI cases is based on a number of procedural safeguards. One essential safeguard is the requirement that the officer observe the suspect for a continuous period of at least fifteen minutes prior to the breath test. This is to ensure that there was no burping, belching or regurgitation during this period. In theory, any such gastric event occuring prior to the observation period, would not effect the results of the test as any resultant alcohol from the stomach would have dissipated from the mouth and throat.
Manufacturers of breath machines stress the importance of this observation period in their manuals, and the California Code of Regulations governing breath test procedures requires it.
However, it has been my experience and the experience of many of my fellow DUI defense attorneys in Los Angeles, that many police officers do not understand the reasons behind this requirement and do not take the need for a continuous period of observation seriously. They will often add on the time spent in a police vehicle transporting the suspect back to the station and then simply go directly to the machine to do the test. Usually, the suspect will be seated in the back of the police vehicle and the arresting officer will be driving. Often the arresting officer will be multi-tasking, filling in paperwork during the observation period, instead of paying attention.
In the absence of a continuous period of at least 15 minutes of observation immediately before the breath test, most experts would testify that the results of the test cannot be considered reliable.