What is the purpose of field sobriety tests?

Field sobriety tests are specifically designed to assess a driver's level of impairment. Law enforcement officers administer these tests to gather evidence concerning a driver's ability to operate a vehicle safely. The tests typically involve a series of physical and cognitive challenges, such as balancing, walking in a straight line, or following an object with the eyes. These tasks gauge various skills that can be affected by alcohol or drug use, such as coordination, balance, and attention.

By evaluating a driver's performance on these tests, officers can make informed judgments about whether the driver is impaired and to what degree. The results can play a critical role in deciding whether further action, such as arrest or chemical testing, is justified. The primary objective is not to prove that a driver is sober or uncomfortable, and it is not inherently aimed at immediate arrest but rather at understanding the driver's capability to drive safely.