When someone is suspected of DUI in Washington, one of the first things law enforcement does is attempt to measure impairment. Officers often rely on field sobriety tests at the roadside and, in many cases, chemical testing such as blood draws once the person is in custody.
DUIs in Washington State
Prosecutors tend to present these results as powerful evidence, framing them as scientific or objective proof of intoxication. But both methods have flaws that can lead to inaccurate conclusions.
Field tests are influenced by stress, health issues, or environmental conditions, while blood tests depend on strict procedures that are not always followed correctly. Understanding these limitations is central to building a defense in an impaired driving case.
Field Sobriety Tests
These tests measure balance, coordination, and focus through tasks like walking a straight line or following an object with your eyes. But they are subjective. Nervousness, medical issues, or uneven ground can all affect performance, making sober drivers appear impaired.
Blood Tests
Blood tests seem scientific, but they are not flawless. Alcohol levels change quickly, meaning a test taken an hour after an arrest may not reflect the driver’s condition at the time. Labs must also follow strict procedures. If samples are mishandled or contaminated, results may be unreliable.
Defenses Involving Testing
Attorneys often challenge whether officers were properly trained, whether equipment was calibrated, and whether the chain of custody for blood samples was followed. These details can make a difference in court.
Why It Matters
Because juries often view these tests as conclusive, highlighting their weaknesses is important. Many people sitting in a jury box assume that numbers on a lab report or an officer’s testimony about a roadside test are beyond question.
In reality, both types of testing are far less certain than they appear. Field sobriety tests can be influenced by nerves, fatigue, or medical conditions.
Blood tests can be compromised by poor handling, equipment problems, or delays between the arrest and the draw. A defense attorney can bring these issues to light, showing jurors that what prosecutors present as “scientific proof” is not always reliable.
By analyzing the testing process and whether procedures were followed correctly, your Washington State criminal defense attorney can refocus the case on reasonable doubt and protect you from being unfairly convicted on shaky evidence.
If you are accused of DUI in Snohomish County, call Snohomish Law Group at 425-517-3847 to speak with Scott Lawrence and begin your defense.
