Name a reason why a subject might be unable to perform SFSTs accurately other than impairment.

A subject may be unable to perform Standardized Field Sobriety Tests (SFSTs) accurately due to medical conditions or physical disabilities. Conditions such as neurological disorders, joint pain, or muscle weakness can significantly affect a person's balance, coordination, and ability to follow instructions, which are critical for performing SFSTs. These physical limitations can mimic the signs of impairment, leading to false conclusions about a person's sobriety.

While other factors, such as lack of experience with driving, distractions from environmental factors, or age-related limitations, can also impact a subject's performance, they do not inherently stem from physiological constraints. Medical conditions or disabilities create tangible obstacles that directly impede a person's physical capabilities, making them the most pertinent reason for inaccurate performance on SFSTs when not under the influence of alcohol or drugs.