Drug DUI Defense in Seattle

Facing a Drug DUI? Put Former-Prosecutor Insight on Your Side

A drug DUI arrest can threaten your driving privileges and disrupt your work and family responsibilities. At Blair Kim Moeller, PLLC, we examine whether the case rests on evidence of impairment, the presence of a substance, or both. Our review may cover the alleged substance, the traffic stop, officer observations, field sobriety evidence, blood-test timing, and your account of what happened.

Our criminal defense practice is led by Mark Blair, a former prosecutor and Judge Pro Tempore. We apply that perspective to cannabis, prescription medication, controlled substances, and combined-substance allegations.

Call (888) 478-4001 to discuss your Seattle drug DUI charge and the evidence that may shape your defense.

Washington Drug DUI Laws & the THC Limit

Washington’s DUI statute allows prosecutors to pursue different theories in drug-related cases. For drivers age 21 or older, one theory applies when a blood test shows a THC concentration of at least 5.00 nanograms per milliliter of whole blood within two hours after driving.

A separate theory applies when cannabis, another drug, alcohol, or a combination of substances allegedly affected the person’s ability to drive. A THC result below 5.00 therefore doesn’t automatically end a case. Lawful use of cannabis or prescription medication also isn’t, by itself, a defense under the statute.

The analysis may differ for drivers under 21, commercial motor vehicle drivers, and people with qualifying prior offenses. The charged theory and complete evidentiary record matter more than the label applied to the substance.

What Blood Testing Can Establish in a Drug DUI Case

Blood toxicology identifies and measures substances in a blood sample. Washington measures THC in nanograms per milliliter of whole blood, but the reported concentration isn’t a direct measurement of driving ability. Its significance depends on factors such as test timing, laboratory methods, officer observations, and other evidence.

Analysis admitted under Washington’s DUI statutes must be performed by an appropriately permitted person or a qualifying laboratory certified or accredited under ISO/IEC 17025 forensic toxicology standards. A result from blood collected more than two hours after driving may still be offered as evidence of THC concentration or alleged cannabis influence, depending on the facts and legal theory.

A review of blood evidence may address:

• Collection and authorization: When, why, and under what legal authority the blood was drawn.
• Chain of custody: How the sample was documented and handled from collection through testing.
• Laboratory procedures: The testing method, quality controls, reporting conventions, and measurement uncertainty.
• Interpretation: Whether the result supports an allegation of impairment or establishes only that a substance was detected.

Potential Defenses to Drugged-Driving Allegations

The available defense issues depend on the police reports, video, laboratory records, court documents, and circumstances surrounding the stop. Mark Blair prosecuted cases in King, Yakima, and Thurston Counties and argued hundreds of criminal cases before moving into criminal defense. That background informs our review of how the prosecution may build and present its case.

Our investigation may examine:

• Whether the officer had legal grounds for the traffic stop and arrest.
• Whether statements, searches, and the blood draw complied with constitutional and statutory requirements.
• Whether field sobriety tests and officer observations support the alleged impairment.
• Whether medical history, tolerance, timing of use, residual metabolites, or multiple substances provide relevant context.
• Whether a drug recognition expert, an officer trained to evaluate suspected drug impairment, followed applicable procedures.

We assess how the evidence fits together before determining whether negotiation, pretrial motions, or trial preparation best fits the facts.

What to Expect in Seattle Municipal Court

Seattle Municipal Court handles gross misdemeanor DUI cases arising within Seattle city limits. A case may proceed through arraignment, pretrial hearings, motions, trial, and sentencing. Its course will depend on the charge, evidence, negotiations, and court rulings.

We begin with a detailed case analysis, request available reports and recordings, review testing materials, and assess potential administrative driving consequences. Our representation emphasizes direct attorney communication, independent investigation, strategic negotiation, and courtroom preparation.

Our team has more than 70 years of combined experience across criminal defense and family law. We’ve served clients in Seattle, King County, and across Washington State since 1996.