California DMV Permit Test (Class C)Alcohol and DrugsHard
Which factor is most reliable in determining a person's level of alcohol impairment?
- AHow long they have been drinking.
- BTheir personal tolerance to alcohol.
- CTheir Blood Alcohol Concentration (BAC).
- DThe type of alcoholic beverage consumed (e.g., beer vs. liquor).
Show answer & explanationAnswer & explanation
Correct answer: C. Their Blood Alcohol Concentration (BAC).
While factors like tolerance, drink type, and duration of drinking influence BAC, the Blood Alcohol Concentration (BAC) itself is the most objective and legally recognized measure of alcohol impairment. It directly quantifies the amount of alcohol in a person's bloodstream, correlating to their level of functional impairment.
Why the other options are wrong
- A. Drinking duration is a factor, but BAC integrates duration, amount, body weight, and metabolism into a single, definitive measure.
- B. Tolerance can mask the outward signs of impairment but does not reduce the actual physiological impairment or BAC.
- D. All standard drinks contain roughly the same amount of pure alcohol; the type of drink itself doesn't inherently change impairment, only the rate of consumption.
Blood Alcohol Concentration (BAC)
BAC is the percentage of alcohol in a person's bloodstream, serving as the primary objective measure of alcohol intoxication and impairment.
- Measured by breath, blood, or urine tests.
- Correlates directly with level of impairment.
- Used to determine legal intoxication.
- Affected by body weight, gender, amount consumed, time, food.
Memory trick: BAC is the Blueprint, the ultimate measurement.