The proposal to lower the blood-alcohol limit for driving from 80mg of alcohol per 100ml of blood to 50mg dates back to at least 2001. That's when I wrote about the difficulties associated with it in Drinkers need method of measuring blood alcohol. My main issue with the suggestion back then was after a couple of drinks most of us have no reliable way of knowing our blood-alcohol level and lowering this level will only make this Russian Roulette-style game even riskier for those operating at its fringes.
But today there's clearly an appetite for taking a harder line on drink driving. Almost two-thirds of those in a recent Herald-DigiPoll survey supported lowering the limit. It seems there's a belief that our roads would be safer if the lawful blood-alcohol level was dropped; there's also a desire to align our limit with that of Australia, France and Germany.
But there's surprisingly little discussion about what impact the proposed measure may have on those people we ought to be very concerned about - that is: recidivist drink-drivers who seem to pay little attention to existing limits. What evidence exists to suggest that this group of dangerous offenders is likely to act more responsibly in the event of a law change?
If the drink drive limit is lowered, I predict that it's the behaviour of the law-abiding masses that will change. Taxis will do a roaring trade, sales of alcohol detectors will climb and non-alcoholic cocktails will become fashionable at last. I reckon it may also help fuel uncharacteristic binge drinking if people accustomed to having a couple of drinks on their way home from work each evening convert this to one massive night out each week (in a taxi or with a designated driver) to avoid falling foul of the reduced limit.
In 2009 a representative from CrossRoads, a Sensible Sentencing Trust subsidiary which aims "to remove hardcore impaired drivers from New Zealand's roads", told the NZ Herald: "Of the 30,000 drunk drivers convicted last year, 10,000 had one previous conviction and 1500 had at least four."