In a standard SFST, what does swaying during the One-Leg Stand indicate?

The observation of swaying during the One-Leg Stand is a significant indicator of impaired balance, which suggests a potential impairment in the subject being tested. This part of the Standardized Field Sobriety Tests (SFST) is designed to assess an individual's ability to maintain balance while performing a simple task under conditions that could be influenced by alcohol or other substances.

When a person sways, it typically reflects a lack of coordination and an inability to maintain a stable posture on one leg, which is crucial for displaying good motor skills and balance. Such behavior is often interpreted as evidence that the subject may be experiencing some level of impairment, either due to substance use or other conditions affecting their neuromuscular control. Maintaining balance is a fundamental aspect of safe driving, and observed swaying raises concerns about the individual's capability to operate a vehicle safely.