Police may arrest a driver on suspicion of driving under the influence, or “DUI,” if they have probable cause that the driver is impaired due to drugs or alcohol. Washington law establishes specific levels of alcohol present in a person’s blood, known as blood alcohol content or “BAC,” in its definition of the offense of DUI. While it is possible to present evidence of a driver’s behavior, including how they were operating the vehicle and how they behaved during the stop, in an effort to prove intoxication prosecutors often prefer to rely on BAC evidence. Different BAC levels, often known as “legal limits,” apply to drivers under the age of 21 and commercial drivers, than the level that applies to adult drivers in personal vehicles. If you have been charged with an alleged DUI offense, you should consult with an experienced DUI attorney who can help you prepare your defense and assert your rights.

Blood Alcohol Content

BAC is the percentage of a person’s blood, typically measured by volume, that is alcohol. A BAC of 0.05 percent therefore means that 0.05% of the person’s blood is alcohol. This amount increases as a person consumes alcoholic beverages, and gradually decreases as the body metabolizes the alcohol. Having a BAC greater than 0.20 percent increases the risk of loss of consciousness and memory blackout, and a BAC over 0.30 percent risks alcohol poisoning or even death. Police can test for BAC with a breath testing device, or “breathalyzer,” or by drawing blood for lab analysis. Exposure to certain substances, including industrial chemicals like acetone, can cause an increase in BAC without necessarily causing intoxication. For this reason, it is critical to have the assistance of an attorney in challenging BAC evidence.

Adult BAC Level for a Washington DUI

The legal limit for DUI for an adult driver in a non-commercial vehicle in Washington is 0.08 percent within two hours of driving. Because of the human body breaks down alcohol over time, a BAC level of 0.08 percent or higher within that two-hour period is presumed by law to be evidence of impaired driving. The state must prove both that the BAC test was accurate and reliable and that the defendant was driving within the applicable time period.

Commercial Driver BAC Level for a Washington DUI

For commercial drivers, the legal limit is 0.04 percent. This applies to individuals with commercial driver’s licenses (CDLs) while they are operating a commercial vehicle, such as a tractor trailer. The added difficulty of driving such a vehicle, the additional skills and licensure required, and the additional danger posed by accidents involving large commercial vehicles led the state to impose a lower BAC for commercial drivers.

Under 21 BAC Level for a Washington DUI

Drivers under the age of 21, who may not legally consume alcohol at any time, commit the offense of DUI under Washington law if they have a BAC of 0.02 percent.

You need the assistance of an experienced Washington criminal defense attorney if you are facing a charge for an alleged DUI offense. Vindicate Criminal Law Group knows Washington’s criminal laws and has experience in its court system. For over twenty years, we have represented defendants charged with alleged DUI in Lakewood, Seattle, and elsewhere in Washington state. Contact us today for your confidential case evaluation, online or at 888-212-4824