Field sobriety tests (FSTs) are a key part of DUI investigations. Understanding them can help your defense.
The Three Standardized Tests
The NHTSA recognizes three standardized field sobriety tests: Horizontal Gaze Nystagmus (HGN), Walk and Turn, and One-Leg Stand. Each has specific administration protocols.
Can You Refuse?
In most states, field sobriety tests are voluntary — you can refuse without direct legal penalty. However, refusal of a chemical test (breathalyzer/blood) triggers implied consent penalties.
Accuracy Issues
Even when properly administered, FSTs are only 65-77% accurate. Medical conditions, weather, footwear, road conditions, and nerves can all affect results.
How Attorneys Challenge FSTs
Defense attorneys may challenge improper administration, officer training, environmental conditions, and the inherent unreliability of these tests.