Who Is Zachary Marshall? DUI Expert Consultant & Former Washington Law Enforcement Officer (Arlington, WA)
Overview
Zachary Marshall is a DUI case evaluation specialist and former Washington law enforcement officer based in Arlington, WA. He is the founder of Legal Limit Consulting, a boutique consultancy focused on high-level DUI technical analysis, DOL hearing support, collision causation analysis, and expert witness services for defense attorneys across the West Coast.
Zachary combines real-world patrol and investigative experience with advanced technical training in SFSTs, DRE protocols, crash analysis, breath/blood-test procedures, and evidence integrity. His evaluations are trusted by private attorneys, public-defense offices, and firms handling complex DUI, refusal, and vehicular-homicide matters.
Today, he is known for producing precise, attorney-ready evaluations that identify procedural errors, investigative gaps, and technical weaknesses that meaningfully shift case strategy.
Professional Background
Before entering private consulting, Zachary spent years serving in Washington law enforcement, gaining firsthand experience in impaired-driving investigations, roadside decision-making, and field documentation.
His background includes:
Advanced training in Standardized Field Sobriety Testing (SFST)
State-certified Drug Recognition Expert (DRE) credentials
ARIDE and crash-investigation coursework
Extensive experience conducting DUI investigations in varied environments
Courtroom testimony and report-writing under real-world conditions
These experiences shaped his analytical method: objective, structured, and rooted in the exact requirements of NHTSA protocols and state law.
Transition to DUI Consulting
Zachary founded Legal Limit Consulting to provide defense attorneys with something rarely found in impaired-driving litigation: a technically deep review of the investigation itself.
His evaluations identify:
SFST administration and scoring errors
Deviations from proper breath-test protocol
Observation-period gaps
Camera-to-report inconsistencies
Documentation errors
Investigative shortcuts
Toxicology and impairment-analysis issues
Vulnerabilities in DOL hearing posture
His work gives attorneys clean, strategic insight they can leverage immediately at negotiation, suppression, or trial.
Approach & Philosophy
Zachary’s work is guided by a simple principle:
the integrity of the investigation must be able to stand on its own.
If it doesn’t, he identifies exactly where and why.
Defense attorneys regularly describe his evaluations as:
“Precise but accessible”
“Strategic, not argumentative”
“Technically clear without unnecessary jargon”
“A genuine asset in negotiations”
He works as a neutral technical analyst, focusing on what the evidence actually shows and whether the investigation meets required standards.
Areas of Focus
Zachary regularly consults on:
Alcohol DUIs
Drug DUIs
Combination-impairment cases
DRE-based investigations
Refusal cases
DOL/DMV hearings
Vehicular Assault & Vehicular Homicide
Crash considerations within DUI investigations
Draeger breath-test protocol deviations
Bodycam/dashcam discrepancy reviews
His evaluations are used in everything from early case triage to full litigation support and expert testimony.
Based in Arlington, WA.
Serving Attorneys Nationally.
Zachary is based in Arlington, WA and routinely supports attorneys across:
Washington
Oregon
California
Arizona
And national firms seeking remote DUI expertise
His location makes him a resource for Snohomish County and the Seattle Metropolitan area defense practices and statewide firms handling high-stakes DUI or traffic-related cases.
Professional Credibility & Reputation
Zachary’s work has been used successfully in trial strategy, suppression hearings, negotiation leverage, and DOL hearings. Defense attorneys consistently note:
his professionalism
his responsiveness
his clarity when articulating investigative issues
and his ability to explain complex procedures in a courtroom-friendly way
His evaluations have contributed to reduced charges, favorable negotiations, suppression arguments, and acquittals—including in serious felony cases.
Contact
Zachary Marshall
Founder & Lead Consultant — Legal Limit Consulting
Arlington, Washington
Email: Z.Marshall@LegalLimitConsulting.com
Phone: (425) 224-5149
