Field sobriety testing

Sobriety checkpoint in Stralsund, Germany

Field sobriety tests (FSTs), also referred to as standardized field sobriety tests (SFSTs), are a battery of tests used by police officers to determine if a person suspected of impaired driving is intoxicated with alcohol or other drugs. FSTs (and SFSTs) are primarily used in the United States, to meet "probable cause for arrest" requirements (or the equivalent), necessary to sustain an alcohol-impaired driving (DWI or DUI) conviction based on a chemical blood alcohol test.