The number of teenage drunk drivers arrested since the introduction of a zero alcohol limit for under-20s has fallen markedly.
In the first nine months since the law was introduced on August the 7th last year, fewer than 3100 teens have been arrested fror drink driving.
More than 6400 arrests were made in the twelve months before the law came into effect.
The Automobile Association says it is e delighted by the fall.
Motoring affairs manager Mike Noon says it appears teenagers find the new law less confusing because they know they should not have had any alcohol at all, instead of having to judge how much they can drink before they break the limit.