New South Wales · Driver Knowledge Test (DKT) · Road safety

After a heavy night of drinking, how long can it take for your BAC to return to zero?

The answer

  • About 8 hours
  • More than 18 hours Correct
  • Exactly 12 hours for everyone
  • About 4 hours

Why that's the answer

It can take more than 18 hours for your BAC to get back to zero, so you may still be over your legal limit for much of the next day. This is why 'I slept it off' is not a defence.

Where this rule comes from

Take the full New South Wales practice test (153 questions)

More NSW DKT questions

Same topic first — road safety trips up more learners than any single rule.

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