BAC limits — Maryland Permit Test

BAC limits on the Maryland permit test — 3 rules, each with the reason behind it and a question on it while it is fresh.

The rules

Driving with a blood alcohol concentration (BAC) of 0.08% or higher is driving under the influence (DUI) per se.

0.08 is the point at which impairment is presumed in law — no further proof of bad driving is needed for the charge.

A BAC of 0.07% is prima facie evidence of driving while impaired by alcohol (DWI).

Impairment starts well below the DUI threshold, so a lower reading can still support the lesser charge.

Drivers under 21, and any driver with an alcohol restriction on their license, may not drive with any alcohol in their system; a reading of 0.02% or more is enough to prove the restriction was broken.

The restriction itself is zero — 0.02% is simply the reading the law treats as proof of it, not an allowance to drink up to.

On the test

At what blood alcohol concentration (BAC) is a driver 21 or older under the influence (DUI) per se?

0.08%. 0.08 is the point at which impairment is presumed in law — no further proof of bad driving is needed for the charge.

How this works

Most practice tests hand you a bank of questions and leave the manual somewhere else. This one puts them together.

You read one law and the reason behind it, then answer a question on that law while it is still fresh. Get it right and you move on; get it wrong and you have found the gap while it is cheap to fix, not on the morning of the exam.

Learning one rule at a time, and proving it immediately, is what turns a manual you skimmed into something you actually know — and it makes studying feel like getting somewhere rather than like waiting to find out.

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Where these come from

Every rule here is checked against Maryland Driver's Manual, published by the Maryland Department of Transportation Motor Vehicle Administration, and against the state code itself. Last checked 2026-08-29.