What is Blood Alcohol Content?
Understanding California Law and BAC
California Vehicle Code § 23152(b) states that it is illegal to operate a motor vehicle with a BAC that equals .08% or more. The term "blood alcohol content" refers to the percentage of alcohol in your bloodstream. Generally speaking, the amount of alcohol in your system is proportionate to your level of alcohol impairment. If convicted of driving under the influence of alcohol, you could face jail time, fines, probation, community service, mandatory rehabilitation programs, and other penalties. If your arrest involved property damage, a child passenger, injury, or death, you could face enhanced consequences and years in a state or federal prison.
BAC and Alcohol Impairment
Each person is uniquely affected by alcohol. It is impossible to predict the level of alcohol impairment. For example, your body weight, diet, and metabolism can determine the how alcohol will affect your ability to function. Generally speaking, the percentage of alcohol in your blood stream will influence your ability to drive in the following ways:
- 0.010%–0.029% - Low BAC levels can only be detected with special testing. The average person will not exhibit signs of impairment at this level.
- 0.030%–%0.059% – At this BAC level, the individual may exhibit fewer inhibitions, mild euphoria, relaxation, and talkativeness. Although a BAC of .059% is below the legal driving limit, it can result in impaired concentration behind the wheel.
- 0.06%–0.09% - Reasoning, visual perception, peripheral vision, glare recovery, and depth perception may be impaired at this level of intoxication. Individuals with a BAC that exceeds .06% may show uninhibited behavior, extroversion, and blunt feelings.
- 0.10%–0.19% - It is illegal to drive at this level of impairment. If your BAC reaches .10%, you may become over-expressive, angry, emotional, or sad. Additionally, your reflexes, gross motor skills, reaction time and ability to speak clearly could be impaired.
- 0.20%–0.29% - a BAC that exceeds .20% can be dangerous. At this level, individuals may lose their ability understand or lose consciousness. Stupor and memory blackouts and alcohol poisoning are common at this level of impairment.
How do police determine BAC?
BAC can be determined using field sobriety tests or chemical testing. Field sobriety testing involves a series of instructions and physical tasks. These task are easy for most unimpaired drivers to complete, but may be difficult for an impaired driver to execute properly. The three most common forms of field sobriety testing are: the one leg stand, horizontal gaze nystagmus testing (HGN), and the walk and turn test. Law enforcement may also use chemical testing to determine a driver's BAC. Chemical tests include breathalyzer tests, blood tests, and urine tests. Breathalyzer testing determines your BAC by sampling the amount of alcohol in your breath and measuring it through a chemical reaction. Breathalyzer testing is a common form of evidence in DUI trials.
BAC, Commercial Drivers, and Underage DUI
California law states that it is unlawful for a minor to operate a motor vehicle with a BAC that exceeds.01%. In other words, minors can be arrested for drunk driving with almost any traceable amount of alcohol in their bloodstreams. Commercial drivers are held to a stricter standard as well. In California, anyone holding a CDL is now allowed to operate a commercial motor vehicle with a BAC that exceeds .04%.