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Understanding DUI "Per Se" Laws

"Per se" laws assume that a person is guilty of driving under the influence of alcohol if the court can show that his / her BAC is more than .08%. According to California law, it is unlawful to drive under the influence of drugs or alcohol. While a person could be "under the influence" with a lower Blood Alcohol Concentration, a BAC that exceeds .08% does not always mean that the driver is intoxicated.

The Problem with California's Per Se Law

The Per se law seems reasonable at first glance: The court only needs evidence that the driver's BAC was above the legal limit to obtain a conviction. After all, a person is DUI if his / her BAC is more than .08%, right? Not always. Some drivers may not actually be "under the influence" of alcohol, even though their BAC is .08%. Alcohol influences each person in different ways; while one driver might feel the effects of alcohol with a .05% BAC, another driver's alcohol tolerance might keep him / her from feeling under the influence with a much higher blood alcohol concentration.

Inaccurate Chemical Testing

During a DUI case, chemical testing is often considered conclusive evidence of DUI. If chemical tests indicated that the driver's BAC exceeded the legal limit, prosecutors can use the per se law to obtain a conviction. Generally speaking, blood samples are the most accurate way to determine the amount of alcohol in a person's bloodstream. Even still, blood tests cannot measure how the alcohol affects your ability to operate a motor vehicle.

Breath tests and urine testing are somewhat less accurate; many factors can influence the outcome of a Breathalyzer test. For example, you are more likely to produce a higher BAC test result if you used mouthwash or haven't eaten.

Arrested for DUI in Orange County? Speak with the Law Offices of Virginia L. Landry, Inc. today.