Which at-scene measurement provides a direct indicator of intoxication?

• A. Breathalyzer reading
• B. Blood pressure
• C. Hair analysis
• D. Eyeglass prescription

Answer: (A)

Measuring intoxication on the scene relies on tapping into the amount of alcohol in the bloodstream. A breathalyzer reading provides a direct indicator because it estimates blood alcohol concentration from a breath sample. The deeper lungs air carries alcohol that correlates with how intoxicated someone is, giving a quantifiable measure of impairment.

Blood pressure is just a vital sign that can vary for many reasons and doesn’t quantify intoxication. Hair analysis shows long-term substance use over days to weeks, not current impairment. An eyeglass prescription has no relation to intoxication.