Breath tests do not measure the amount of alcohol in your blood, which is what California DUI laws are based on.
Therefore, breath test results can be an unreliable measure of how much alcohol a person has consumed (blood tests may also be inaccurate, though they are generally considered more reliable).
Breath test equipment is highly technical and unless the arresting officer is properly trained in following the correct procedure, the evidence may be challenged by an experienced Orange County DUI attorney. If a person hiccups, belches, or vomits within 15 minutes of a breath test, the instrument may register an inaccurately high blood alcohol concentration.
In addition to the above and, amongst other issues, uncalibrated testing equipment, instrument malfunction, improper handling by a police officer, tainting of samples, and outside interference may provide a defense against a high blood alcohol concentration.
Your health and physical condition may also affect breath test readings (discussed in more detail below).
Another factual defense against a DUI charge is a rising blood alcohol level.
It is important to remember that you are allowed to drink before driving in California as long as your blood alcohol level (BAC) remains below 0.08 percent at the time of your driving and as long as you are not impaired for the purposes of driving a motor vehicle.
The critical element of your BAC level is what your BAC was while you were driving – not before or afterward.
When you ingest alcohol, your blood absorbs the alcohol and your BAC rises until it reaches its peak level. It may take 30 minutes to 2 hours for the alcohol to become completely absorbed into the bloodstream from when the alcohol was consumed. The actual time may vary based on the concentration of the alcohol and whether the consumer has an empty stomach or is drinking while eating.
If you were stopped soon after consuming an alcoholic beverage, your alcohol level could have been rising from the time you were driving to the time the chemical test was administered. If this is the case, the test may result in a BAC that exceeds the legal limit at the time the test was administered, but you may have been under the legal limit at the time you were driving.
Title 17 of the California Code of Regulations outlines the requirements for collecting, storing, and analyzing the evidence used for the chemical tests taken during the DUI investigations.
A series of specific steps must be followed when performing and processing these tests and if there were any missteps by law enforcement, an experienced DUI defense attorney may succeed in having crucial evidence excluded from the prosecution’s case.
Officers must also read your “Miranda” rights prior to interrogating you after a DUI arrest. Failure to follow this basic procedure can lead to a hearing where evidence during or resulting from the interrogation may be excluded from the case.
Certain medical conditions can skew the readings of breath tests and chemical tests designed to identify the blood alcohol level of drivers.
For instance, gastroesophageal reflux disease (GERD), acid reflux, or heartburn can artificially inflate breath test results.
Prescription medications for certain conditions and diets can also pollute BAC readings on breath and chemical tests. These include common conditions like diabetes as well as high protein/low carb diets, which may give inaccurate readings on testing equipment.