According to plans being drawn up by coalition ministers, the drink-drive limit could drop to 50mg of alcohol per 100ml of blood, down from 80mg.
This could mean that a single glass of wine or a pint of strong beer or cider could push many people over the limit, particularly women.
The limit could be even lower for new drivers with less than five years of experience behind the wheel. The proposals are for that to be 20mg per 100ml of blood.
The limit has been at 80mg for the last 40 years, since the introduction of the breathalyser.
The plans were drawn up by Sir Peter North for the Department for Transport. They've been met with support by the British Medical Association and The AA.
The Department for Transport estimated that, in 2008, 13,020 reported casualties happened when one of the drivers involved was over the limit. This number accounted for 6 per cent of road casualties that year.
An argument against lowering the limit, proposed by the Federation of Licensed Victuallers Associations (FLVA), contends that drivers who fall foul of drink driving laws under the new proposals may not be stigmatised in the same way that they are now. They argue that public perception may well soften with a lower limit in place.