If you've been stopped for suspected DUI in Washington, the officer likely asked you to perform a series of physical tests before deciding to arrest you. These field sobriety tests (FSTs) are presented as objective science. They are not. Here's what you need to know.
The Three Standardized Tests — and Their Flaws
1. Horizontal Gaze Nystagmus (HGN)
The officer tracks a pen or finger across your field of vision and looks for involuntary eye jerking (nystagmus). While HGN is the most scientifically supported of the three tests, its accuracy depends heavily on proper administration. Officers must hold the stimulus at the correct angle, move it at the correct speed, and hold it for the correct duration. Deviations from the protocol invalidate the results.
More importantly, HGN can be caused by conditions entirely unrelated to alcohol — including inner ear problems, certain medications, brain injuries, and even caffeine in high doses.
2. Walk-and-Turn (WAT)
You are asked to walk heel-to-toe along a line, turn, and walk back. Officers look for 8 clues of impairment including stepping off the line, using arms for balance, and improper turn technique. The test is performed on the side of a road, often in the dark, on uneven pavement, with traffic passing. These conditions alone affect performance.
Shoes matter enormously. High heels, boots, or simply footwear you're not accustomed to walking in can dramatically affect WAT performance without any alcohol involvement.
3. One-Leg Stand (OLS)
You must stand on one foot and count to 30. Again, officers look for specific "clues." People over 65, with knee or ankle injuries, back problems, or inner ear issues routinely fail this test regardless of sobriety.
The Dirty Secret: Pass or Fail, the Evidence Still Gets Used
Here's what many people don't realize: in Washington, DUI arrests happen regularly even when people pass all three tests. Officers often testify that you passed the tests but still appeared impaired based on "other observations." This is why these tests are fundamentally unfair — passing doesn't get you out of an arrest, but the results are used against you if you're arrested.
How Janet Bergstrom Challenges Field Sobriety Test Evidence
As a former King County Deputy Prosecutor, I built DUI cases around FST evidence. Now I know exactly what to look for when challenging it. Specific areas of attack include: officer training records, video footage showing improper administration, environmental conditions at the time of testing, medical conditions affecting performance, and deviation from the National Highway Traffic Safety Administration (NHTSA) standardized protocol.
If the officer deviated from the standardized protocol — even slightly — we can move to exclude FST evidence entirely. Without FST evidence, many DUI cases collapse.