From today, the drink-drive limit has been lowered to 250 micrograms of alcohol per litre of breath or 50 milligrams per 100ml of blood. The law change aims to reduce the number of alcohol-related crashes – which have killed or injured about 6400 New Zealanders over the past 10 years. Michael Forbes at The Dominion Post looked at the science behind how people should change their drinking habits to account for the new limits.
An excerpt (read in full here):
A couple of after-work drinks will still be okay under the new drink-drive limit but consuming water is unlikely improve your odds of passing a breath test, scientists say.
There is no simple way of telling how much you can have and still be all right to drive because a person’s blood-alcohol level depends on their weight, how much time they spend drinking and how much food they have eaten.
The larger you are, the more body water you have to dilute the alcohol. Women usually need to be more careful than men because they tend to have about 10 per cent less body water.
But ESR forensic toxicologist Sam Coward said there will still be room for a few responsible drinks before you get behind the wheel, regardless of your size or gender.
“Unless you’re a tiny person, you’re going to be able to have two or three small glasses of wine or beers over a couple of hours and still be within the new limit.”