I am steadily becoming frustrated by the perpetual and growing lottery that is alcohol and driving.
In December, new legal alcohol limits - lower than right now - will come into force, dropping the limit to just over half what it is now.
Most people I know who drink have worked out something like a mathematical sequence of events in terms of consumption of alcohol over time and food.
It is, of course, not remotely mathematical at all, but familiarity has made them confident of what they can drink and be safe to drive. Well, this new limit is going to catch a lot of people out.
I think what depresses me is the police and transport infrastructure - and enforcement - around alcohol is so immense, and takes up so much resourcing.
We frequently get letters to the paper, following a substantial checkpoint, from people complaining that police resourcing could be better utilised elsewhere.
These letters say more about the writer than anything else; they speak volumes for the lack of awareness of how big the problem is.
Alcohol is such a straightforward thing, but its impact on society is far greater than smoking, drugs or obesity.
I am sure the police feel just as much frustration as we do about the resourcing that alcohol enforcement requires, but New Zealand society is the architect of its own misfortune.
And so will you be, if you want to start "computing" how much you can drink under these new laws. As we discovered, there is no "set" number of drinks that will tip you over, because it can differ from person to person.
I know people who wouldn't want to drive after half a glass of wine. I have also met the opposite extreme.
I've had a family member who had to be driven everywhere because he lost his licence. It's embarrassing for both because of the obligation, and it's a logistical nuisance.
Have a think on what it would be like to be driven everywhere, like some child. Think on that, before "calculating" your limit.