The definition of a DUI entails the driver consuming or ingesting any intoxicating substance or combination of substances that impairs one's ability to safely operate a motor vehicle, as defined by applicable state statutes. The intoxicating substance is not limited to drugs or alcohol but can include prescription or over-the-counter medications. There are two ways an arresting officer in Washington attempts to determine if a person is driving under the influence.
The first method of ascertaining a driver's level of intoxication is by blood or breath analysis. For an adult of legal drinking age, a blood alcohol level of .08 or more is considered impaired. The threshold level is half that for commercial drivers and half again for underage drivers. The other method police may use is more subjective and relies on the driver's appearance and signs of alleged intoxication.
If the Washington Department of Motor Vehicles receives notification of your DUI arrest in another state, your driving privileges can be impacted here as well. If you have been arrested on suspicion of being impaired, you are permitted to request a hearing on the charges within 20 days of the arrest. If you do not request a hearing or the ruling goes against you, then your license may be suspended for up to two years, based on prior history and the seriousness of the alleged offense.
There are two tiers of driver's license suspension or revocation, depending on whether Washington prosecutors gain a conviction on the driving under the influence charge. If you find yourself in the situation of having been arrested and charged with DUI, you may benefit from the assistance of experienced defense counsel. Every case is unique and will require the best defense tailored to your situation in order to pursue a resolution that serves your circumstances best.
Source: dol.wa.gov, "WA State Licensing (DOL) Official Site: Driving under the influence", Oct. 24, 2014