Dialogue: Drinkers need method of measuring blood alcohol

If the drink-driving alcohol limit is to be lowered, we should at least have a way of checking if we are legal, writes SHELLEY BRIDGEMAN.

The prospect of lowering the drink-driving alcohol limit from 80mg to 50mg per 100ml of blood just re-emphasises all the old issues inherent in the concept of such a limit.

It's not the concept itself that is flawed; in theory it is a logical and tidy little law. Rather, it is the fact that in practice each person is unable to measure their own blood-alcohol levels that makes it such a farce.

At least with other offences we have the capacity to know if we're on the wrong side of the law. If you steal, commit assault or murder, at least you know you're in trouble; it's a clear-cut thing.

But what chance does anyone have of gauging precisely whether their blood-alcohol happens to be 82mg or 79mg?

Lowering the level would only exacerbate this untenable situation. "Officer, I could have sworn it was 49.5mg, not 50.2mg."

Even under the present system, it's purely a game of Russian roulette. Every time we drive a car without an alcohol-free day under our belt we run the risk of breaking the law.

One night a friend of mine was stopped to be breath-tested. She had had a few drinks, so was delighted to pass. Imagine her glee when, armed with the secret knowledge that she was right as rain, she was stopped five minutes later by a different breath-testing crew. Her smile soon disappeared when this time she was deemed to be over the limit and whisked away to the police station. How arbitrary is that?

That means that even if we had the ability to accurately gauge our own blood-alcohol levels, we would need to perform the test at several-minute intervals to have a reliable reading.

To complicate things further, a whole raft of other impossible-to-measure elements affect blood-alcohol levels, such as food intake, capacity for alcohol, tiredness levels and stress levels.

And, if you are a woman, you can throw in extra factors such as the fact we have lower body weights than men and, of course, the perennial influence of hormones.

At least in the 1980s, pubs had machines with a straw you blew into to measure your level. Whatever happened to those things?

Of course, they were my student days - and (being carless) we used them only to see how high a reading we could get. But at least they were there for concerned drivers, too.

A few years ago I was driving home after a wedding reception. (Usual story, the newly-weds had abandoned their guests for a few hours before dinner - and drinking was the only diversion.) When I was stopped at a road-block I was worried that it might be all over red rover - goodbye licence, hello buses - but by the time I had blown in the bag (not an easy task, incidentally) I was cleared.

The point of this story, though, was the pure fear I felt when I was pulled over. I suffered the sort of knee-wobbling anguish that robbers must feel when they are about to be caught by the cops.

But I'm a law-abiding citizen - why should I have to experience this just because there happens to be a law relating to blood-alcohol measurements over which I have no fail-safe control?

Clearly, if the law-makers are considering lowering this limit, they must be blind to the practical flaws in the present system. Apparently they are completely relaxed that every driver who has had a drink is totally mystified about their legal status until that defining moment when they are stopped.

I hosted a small drinks party the other night and when I went to top up my guests' drinks they all muttered something about driving and wondered how much more they could have - even while they were still on their first glass.

If that is the behaviour generated by an 80mg limit, imagine our responses to a 50mg limit. "Just a spoonful for me thanks, I'm driving." Or perhaps "I've already had a sip tonight so I might just gargle with this."

It's so unscientific. We spend our lives wondering. I wonder whether I can have one more drink. I wonder if half a packet of crisps counts as food. I wonder if it's been an hour since my last drink.

Effectively we are all just gambling with our drivers' licences. At the very best we are speculating or making an educated guess. Even so-called experts cannot agree about safe drinking levels.

Perhaps there's an opportunity for a new game show: Guess what my blood-alcohol level is?

If the limit is reduced, the only dependable response is to never drive after consuming alcohol. And if that's what the law-makers really want, why can't they be upfront about it and simply put a zero-limit law in place? At least then we would all know where we stand.

And if they are not going to do that, surely they have an obligation to provide us with reliable tools for measuring our own blood-alcohol levels.

* Shelley Bridgeman is an Auckland writer.