What Evidence is Needed for a DUI Conviction in Washington State?

For a jury to find you guilty of driving under the influence (DUI) in Washington state, there needs to be compelling evidence that proves your guilt. Fortunately, when you are on trial for a DUI, your Washington state DUI attorney understands police procedures, types of evidence, and how to challenge it. 

What is Considered a DUI in Washington? 

The law in Washington considers a motorist to be driving under the influence when they are impaired by alcohol, marijuana, and other drugs. Alcohol and drug tests will be administered within two hours after driving to determine if the driver’s blood alcohol concentration (BAC) is .08 or higher if there is a THC concentration of 5% or higher. 

Commercial drivers will be charged with a DUI if their blood alcohol content is 0.04% or higher. Since they drive for a living, the state holds them to an even higher level of accountability than the average vehicle operator. 

The rules are even more strict for individuals under 21 years of age. A BAC of 0.02% will see them charged with a DUI. This means that if a driver is under 21, they must not have a drink at all and get behind the wheel because the penalty will be steep.

What is the Process of a DUI in Washington State?

There are several steps in the DUI process. It is beneficial to have a Washington state DUI attorney to navigate the entire complex process for you. We will start at the beginning and work our way through explaining the process. 


The arraignment is a mandatory hearing where you will enter your plea to the court, you must consult with your lawyer before doing this. At the hearing, the conditions of your release are set if the judge sees fit. 

The court will determine whether releasing you will put your community at risk or if you pose a flight risk. This will be decided by the judge’s review of your criminal history, your roots in the community, and your breath test or refusal to participate. 

Normally, the arraignment takes place soon after the arrest, in most cases, within 30 days. 

But, legally, the prosecution can file their charge up to two years. 

Pretrial Hearing

The pretrial hearing is where negotiations begin. If negotiations go well, the case can be resolved or dismissed then, though it may take more than one hearing to arrive at a suitable result. Your DUI defense attorney will receive information about your arrest and begin their investigation. 

If the pretrial process did not resolve the charges, then the case moves on to the next step before going to trial. 

Evidentiary Hearing

At the motion hearing, the court rules on which evidence is allowed at trial. Law enforcement testimony is permitted, and your DUI attorney will have the chance to question them. The judge will listen to arguments about the evidence and rule on it. 

Your defense team will have prepared a persuasive case as to which evidence should be suppressed. If things go well, the process may stop here. If the prosecutors do not have enough evidence to successfully convict you, the case will be dismissed. 

But, if the case is not resolved at this step, you will move on to the next phase, the trial.


Your attorney will be prepared to argue that you should not be convicted. The defense may argue that there was insufficient evidence or about of procedural issues with your arrest. 

The prosecutor will introduce evidence and testimony of police officers, witnesses to the alleged crime, and expert witnesses. Following that, your attorney will then cross-examine the witnesses. If there is evidence or testimony that can support your case, it will be presented as well.


After both sides have presented their case, the judge or the jury will deliberate until they decide your guilt or innocence. In the case of a not guilty ruling, the case will be dismissed. If you are found guilty, the conviction will be entered. DUIs are permanent in Washington state. They cannot be removed or expunged for any reason. 

If you and your legal team believe that there was mishandling of the law or a problematic evidentiary ruling, you can take the next step, which is an appeal to a higher court. 

What is admissible in Court for a DUI Case?

When you are in court for a DUI, though the law enforcement officers who arrested you may testify, that testimony rarely convinces a jury without other evidence to back up their side of the story, the prosecution must present evidence that convinces the jury that you were impaired and broke the law by driving that way.

Below are the types of DUI evidence that can be admissible in court:

  • Field sobriety tests
  • Chemical sobriety tests
  • Declined sobriety tests may be used against the defendant
  • Testimony of the arresting officers
  • Crime scene evidence
  • Drugs or alcohol found at the scene
  • Expert testimony

Washington State DUI Lawyers

An experienced Washington State DUI lawyer can help you navigate each phase of your DUI journey, from arraignment to dismissal. We will investigate your case, analyze the evidence, and find the way that the resolution of the case will most positively impact you.


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For a free consultation to discuss your pending case or other legal matters, please call us any time at 425-452-1600 or complete our online contact form. Our attorneys will explain the entire process surrounding your charge and remove the fear and uncertainty regarding your arrest. Our team should be your first call if you need a top-rated, dedicated, and responsive DUI/DWI or criminal defense attorney. If success in your legal matters is your only option, we hope that you will place your trust in top-rated Washington State DUI attorney Robert Ault.  

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