What is the purpose of Field Sobriety Tests during an OUI enforcement?

Field Sobriety Tests (FSTs) are specifically designed to assess driver impairment, particularly in situations where law enforcement suspects a driver may be operating under the influence (OUI). These tests evaluate various physical and cognitive functions that are often affected by alcohol or drug use. For instance, tasks that require balance, coordination, and the ability to follow instructions can reveal impairments that are not typically visible in a normal driver.

The tests provide law enforcement with measurable indicators of a driver's ability to operate a vehicle safely. Successful completion of FSTs generally suggests that the driver is not impaired, while failure may give officers probable cause to further investigate, which can include breathalyzer tests or arrest. Therefore, the primary objective of FSTs is not related to vehicle mechanics or compliance checks but to directly evaluate the suspect's level of impairment in relation to safe driving.