For a driver aged 20 or over who does not hold a zero-alcohol or alcohol-interlock licence, which blood-alcohol limit applies under the national rules?

Explanation

The ordinary age-based ceiling is 50 milligrams of alcohol in each 100 millilitres of blood for this driver. A figure of 80 marks the upper end of a higher infringement range, while a zero-alcohol or alcohol-interlock licence permits no alcohol at all.