Gerard Vaughan: NZ lags on drivers' blood-alcohol level

Eighty-five per cent of respondents in a road safety survey said drivers should be limited to two or fewer drinks, which fits with a level of 0.05. Photo / Dean Purcell

New Zealand is lagging behind the rest of the world in the amount of alcohol it allows drivers to legally drink before getting behind the wheel.

The Ministry of Transport's Safer Journeys strategy includes a proposal to lower the legal adult blood-alcohol content for driving from 0.08 (80mg alcohol/100ml of blood) to 0.05mg.

In its response to the strategy, the Government approved a number of measures including a zero alcohol tolerance for drivers under 20. It has, however, deferred a decision on the adult level to later this month. It will also consider the option of undertaking more research into the risk posed by drivers with a blood-alcohol content between 0.05 and 0.08.

In my view, the time for more research is past. It is time for action. The evidence for a lower blood-alcohol content is overwhelming.

Since the 0.08 for adult drivers was set in 1978, New Zealand and international research has consistently demonstrated that an alcohol limit of 0.05 or lower saves lives and prevents serious injuries. In Australia, New South Wales achieved an 8 per cent reduction in fatal crashes, and Queensland achieved an 18 per cent reduction.

In Europe, Belgium achieved a 10 per cent reduction in all alcohol related fatalities and France achieved a 30 per cent reduction in alcohol related fatal crashes.

Most countries with legal blood alcohol limits set a limit of 0.05 or lower, which is also the limit recommended by the World Health Organisation as key to reducing alcohol related deaths and injuries.

Safer Journeys estimates that an adult drink-drive limit here of 0.05 would save between 15 and 33 lives and prevent 320 to 686 injuries every year. This corresponds to an estimated annual social cost saving of between $111 million and $238 million.

One objection to lowering the blood alcohol content is that there is insufficient evidence that driving between levels of 0.05 and 0.08 is unsafe. However, the evidence is clear that compared to a sober driver, a driver aged over 30 is 16.5 times more likely to have a fatal crash at 0.08 and 5.8 times more likely at 0.05.

International experience also shows that one of the key strengths of a lowered limit would be its ability to reduce the number of drivers with very high blood-alcohol content levels. For example, in the Australian Capital Territory a lower limit achieved reduced the number of drivers randomly breath tested with levels between 0.15 and 0.2 by a third.

One reason a lowered limit is effective is that it encourages drivers to keep a better count of the number of drinks they consume in order to stay within the limit. A level of 0.05 means people are making responsible decisions to either stop drinking or to not drive before their judgment is significantly impaired.

One way to deal with drivers is to introduce compulsory alcohol interlocks connected to a vehicle's ignition. These devices mean a recidivist drink driver must take a breath test before starting the car. If the driver fails, the car will not start. Interlocks have proved to be effective overseas in preventing drink driving, particularly in association with treatment and education.

Some people are concerned that a 0.05 limit would prevent a glass of wine with dinner or a drink after work. However, a level of 0.05 is consistent with a social drink. Australian guidelines for 0.05 suggest the limit for men is two standard drinks in the first hour and one standard drink per hour thereafter. For women the limit is one standard drink per hour.

Our current level of 0.08 allows people to become significantly impaired and still legally drive. It allows a man of average height and weight to consume six standard drinks within 90 minutes: he could drink almost a bottle of wine and get behind the wheel legally. For a woman it allows four standard drinks to be consumed - that's almost half a bottle of wine.

A limit of 0.08 is above what the public overwhelmingly consider a reasonable limit. The Ministry of Transport's 2009 Public Attitudes to Road Safety Survey found 85 per cent of people said drivers should be limited to two or fewer drinks before driving, which fits with a level of 0.05.

Successive Governments have put the issue in the too hard basket. Now is the time to accept the evidence and take the necessary action to improve the road safety for all of us.

* Gerard Vaughan is chief executive of the Alcohol Advisory Council.