Alcohol, Drugs & DUI

A commercial driver in California is considered DUI at a BAC of 0.04%, half the 0.08% limit that applies to regular drivers. People often select 0.08% out of habit, but the law holds commercial operators to a stricter standard because of the size and risk of their vehicles.

In California a driver 21 or older is legally DUI per se at a BAC of 0.08% or higher. The 0.04% limit applies to commercial drivers, and 0.01% applies to those under 21 under zero tolerance, so picking 0.04% confuses the commercial standard with the standard license limit.

In California a driver 21 or older is legally DUI per se at a BAC of 0.08% or higher. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.

• !The 0.08% figure is the adult per se limit, which tempts test-takers who forget that underage drivers are held to a far stricter standard.

Answer each from memory — you'll see instantly whether you're right and why.

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