DUI - Blood Alcohol Concentration Limits in California

In California, it is illegal to operate a vehicle with a Blood Alcohol Concentration (BAC %) of 0.08% or higher, as a general rule. This is known as Driving Under the Influence (DUI). This BAC % limit may be lower in other cases. To simplify, the table below are the limits set for each case, depending on which limit is applicable under the circumstance:

Being arrested for driving under the influence of alcohol beyond the BAC percentage prescribed by law can lead to serious consequences including criminal charges. In the event of conviction for a DUI criminal charge, penalties imposed can be imprisonment, license suspension, fine, and/ or probation.

Measuring Blood Alcohol Concentration levels

BAC percentage (%) refers to the quantity of alcohol (in grams) per 100 millimeters of blood. In California, there are three acceptable means or chemical tests for measuring the BAC levels of drivers, namely: (1) breath test; (2) blood test; and (3) urine test.

a.) Breath Test

There are two types of breath test done in California. These should not be confused with each other:

1. Preliminary Alcohol Screening Tests. This is more commonly known as the PAS test. This is administered whenever a driver is pulled over after finding probable cause that the driver may be under the influence of alcohol and/or drugs. This test is achieved through the use of a breathalyzer to measure the BAC % of a driver suspected of being in DUI. Note that at this stage, the driver may refuse to take the PAS test without having to face any consequence for refusal.

2. Post-arrest Breath Test. This test is conducted at the local police station after the police officer has determined that you have committed a DUI offense. The results of this test is the one presented in evidence and submitted in court to determine whether or not you have committed a violation of Vehicle Code 23152(b), driving under the influence with BAC of 0.08% or higher. This is different from the PAS test, in addition to the manner of obtaining results, but also with respect to the consequences upon refusal. It is important to remember that refusal to take the chemical test, which may be a breath test, can result in a minimum of one-year license suspension. [California Vehicle Code section 23612(a)(1)(d)]

If a driver is pulled over and suspected of DUI, they may be asked to take a breath or blood test to determine their BAC. Refusing to take a test can result in a suspension of the driver's license, even if they are later found to be innocent.

b.) Blood Test

Blood tests are considered the most accurate method for determining a person's blood alcohol concentration because they directly measure the alcohol in the blood. This is true, however, only if the test is conducted in accordance with the prescribed procedure. These tests are performed only by licensed state officials [ Vehicle Code 23158(a). See also 7 California Code of Regulations § 1219.1(a): “Blood samples shall be collected by venipuncture from living individuals as soon as feasible after an alleged offense and only by persons authorized by Section 23158 of the Vehicle Code.”] and a sample of the driver's blood is sent to a laboratory for analysis. However, it may take several weeks for the test results to be available. One advantage of a blood test over a breath test is that a portion of the sample can be saved for independent testing by the driver's lawyer.

c.) Urine Test

Urine test is not typically used to measure blood alcohol concentration in California DUI cases because they are less accurate than blood or breath tests for determining the specific amount of alcohol present. They can detect the presence of alcohol, but not the specific amount. In California, a urine test will only be used if a blood or breath test is not available or if the person arrested is unable to take one of the tests due to a medical condition or high level of inebriation. [Vehicle Code 23612(a)(2)(A).] The factors that make an individual incapable of taking a blood or breath test may include breathing disorder, clotting disorder, or unconsciousness.

Refusal to take Chemical Test after DUI Arrest

After having been determined by the police officer that you are driving under the influence of alcohol, your BAC levels will now be determined via chemical test - which could be any of those three tests mentioned in items (a) to (c). Unlike the PAS test, a person cannot refuse to take the chemical test without facing consequences. As such, if the person refuses to undergo the chemical test, he/or she may suffer revocation of driver’s license for a minimum period of one-year, additional jail time (if convicted of the criminal charge), and an increased minimum period of nine months in DUI school instead of three. [California Vehicle Code 13353]

Not all instances of chemical test refusal, however, are unfavorable to the driver. There may be cases when refusing to take the chemical test may be the best option as it would result in the least severe punishment to the driver (as compared to submitting to the BAC chemical test). This is especially true when the driver’s level of drunkenness will probably result in a very high blood alcohol concentration level of 0.15% or higher. In this particular scenario, it may prove beneficial to the driver the refuse chemical test since being found with this very high level of BAC % could lead to harsher penalties. [California Vehicle Code 23578]

Consequences of being found to drive under the influence of alcohol beyond the legal limit

If a driver is found to have a BAC of 0.08% or higher, they can be charged with DUI. Penalties for a first-time DUI conviction can include fines, jail time, and the requirement to attend a DUI education program. Repeat offenses can result in harsher penalties, including longer jail sentences and the installation of an ignition interlock device on the offender's vehicle.

Additionally, California has a "zero tolerance" law for drivers under 21, meaning that if a driver under 21 is found to have a BAC of 0.01% or higher, they can be charged with DUI.

It's important to note that a driver can still be charged with DUI even if their BAC is under 0.08%. If a driver is under the influence of drugs or alcohol and their ability to drive is impaired, they can be charged with DUI.

Overall, it is illegal to drive with a BAC of 0.08% or higher in California, and refusing a test may result in the suspension of the driver's license. Penalties for DUI may include fines, jail time, and the requirement to attend a DUI education program. Repeat offenders can face harsher penalties. Additionally, California has a "zero tolerance" law for drivers under twenty-one (21) years old, meaning that if a driver under the age of 21 is found to have a BAC of 0.01% or higher, they can be charged with DUI.