Blood alcohol — New Jersey Permit Test
Blood alcohol on the New Jersey permit test — 5 rules, each with the reason behind it and a question on it while it is fresh.
The rules
In New Jersey it is illegal to drive with a blood alcohol concentration of 0.08 percent or higher.
It is the line the law draws, and impairment starts well below it.
In New Jersey, it is illegal for an individual to drive while under the influence of intoxicating liquor, narcotic, hallucinogenic or habit-producing drugs, or with a BAC of 0.08 percent or higher.
For a driver under 21 it is illegal to drive with a blood alcohol concentration of 0.01 percent or higher.
Under 21 the drinking itself is already illegal, so the driving limit is set at almost nothing.
For individuals younger than 21, it is illegal to drive with a BAC of 0.01 percent or higher.
At a blood alcohol concentration slightly above 0.05 percent the risk of causing a crash doubles.
The risk is climbing well before the legal limit, which is why the manual gives the figure.
If a motorist has reached a BAC of slightly above 0.05 percent after drinking, the risk for causing a motor vehicle crash doubles.
At a blood alcohol concentration of 0.15 percent the risk of causing a crash is 25 times as great.
It is not a gentle curve. Each extra drink multiplies the odds rather than adding to them.
The risk is 25 times as great when driving with a BAC of 0.15 percent.
Blood alcohol concentration is set by four things: how much was drunk, body weight, how fast it was drunk and food eaten.
Two people at the same table can be far apart, which is why nobody can judge it by feel.
BAC is determined by four factors:
On the test
What blood alcohol concentration is illegal for a New Jersey driver over 21?
0.08 percent or higher. It is the line the law draws, and impairment starts well below it. New Jersey Driver Manual, p.115: “In New Jersey, it is illegal for an individual to drive while under the influence of intoxicating liquor, narcotic, hallucinogenic or habit-producing drugs, or with a BAC of 0.08 percent or higher.”
How this works
Most practice tests hand you a bank of questions and leave the manual somewhere else. This one puts them together.
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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 New Jersey Driver Manual, published by the New Jersey Motor Vehicle Commission, and against the state code itself. Last checked 2026-09-15.