What role do field sobriety tests play in a DWI arrest?

Field sobriety tests are an important component in assessing a driver's level of impairment during a DWI arrest. These tests are designed to evaluate various physical and cognitive functions that can be affected by alcohol or drugs. Common tests include the horizontal gaze nystagmus, walk-and-turn, and one-leg stand, each of which measures different aspects of a person's motor skills and decision-making abilities.

While officers often use the results of these tests to form an opinion about a driver's impairment, they do not serve as the sole basis for an arrest. They are part of a larger process that may include observations of driving behavior, chemical tests (like breath or blood tests), and other evidence. Furthermore, field sobriety tests are standardized assessments that officers are trained to administer, making them an essential tool in DWI investigations rather than optional assessments that are infrequently employed.

Lastly, these tests do not measure blood alcohol concentration directly; instead, they provide behavioral indicators of impairment that might prompt further investigation, such as the use of a breathalyzer or another chemical test to confirm alcohol levels. This multifaceted approach helps ensure that law enforcement conducts a thorough and fair assessment of a driver's impairment.