What is the primary component measured to assess intoxication level?

The primary component measured to assess intoxication level is blood alcohol concentration (BAC). BAC indicates the amount of alcohol present in an individual's bloodstream, usually expressed as a percentage. This measurement is crucial in determining impairment due to alcohol consumption, as it correlates directly with the effects of alcohol on the nervous system, motor skills, and cognitive functions.

Other methods and indicators, such as pulse rate, blood pressure, or carbon dioxide levels, do not specifically measure the effects of alcohol. While vital signs like pulse and blood pressure can reflect general health or stress levels, they do not provide a direct assessment of intoxication. Therefore, BAC is the most reliable and widely used metric for evaluating a person's level of intoxication in both legal and clinical settings, making it the correct answer in this context.