Driver's License Test Prep
California Practice DUI & Impaired Driving

You are 25 years old, driving your personal car, not driving a passenger for hire, and not on DUI probation. What is the lowest blood alcohol concentration (BAC) that makes it illegal for you to drive?

  1. A.
    0.04%
  2. B.
    0.08% Correct
  3. C.
    0.10%
The Why

The answer is "0.08%"

For a driver over 21 in a personal car, California sets the BAC limit at 0.08%. Choice A picks the neighboring line in the printed BAC list, applying the commercial or for-hire threshold to a driver whose situation the question tells you is not either of those.

Why the others miss

The traps in the wrong answers

A. 0.04%

The 0.04% figure applies only to commercial drivers and to drivers carrying a passenger for hire, not to a driver in a personal car. This answer picks the neighboring line in the printed BAC list because the adult and commercial thresholds sit one on top of the other on the page.

C. 0.10%

California's adult BAC limit is 0.08%, not 0.10%; 0.10% is not the legal threshold for this driver category. This answer carries forward the 0.10% cutoff from older state laws that pre-dated the nationwide move to a 0.08% standard.

The Rule

This question tests your knowledge of DUI & Impaired Driving in California. Source: California Driver Manual, "Blood Alcohol Concentration (BAC) Limits," p.73..

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