Which symptom might suggest a driver has consumed alcohol during field testing?

Inconsistent eye movement is a key indicator that a driver has potentially consumed alcohol. During field testing, law enforcement officers look for specific physical cues that could suggest impairment. Alcohol can affect the nervous system and motor coordination, leading to difficulties in sustaining smooth eye movement.

One common test used by officers is the Horizontal Gaze Nystagmus (HGN) test, which assesses the eyes' ability to follow a moving object smoothly. If a driver exhibits inconsistent or jerky eye movements, it might indicate impairment due to alcohol consumption. This symptom is particularly significant because it can manifest even at lower levels of blood alcohol concentration and is a reliable indicator of impairment.

The other symptoms listed do not correlate with alcohol consumption. Excessive blinking could occur for various reasons unrelated to intoxication, such as nervousness or a health issue. Clear speech would typically suggest that a driver is not impaired, as alcohol often slurs speech or makes it less coherent. A calm demeanor might be misinterpreted; some individuals may seem unaffected by alcohol, even when impaired, making it an unreliable sign of sobriety.