A lower drink-drive level will make Kiwis safer on the roads

OPINION: It's time to weigh the arguments of opponents against the evidence, writes Ross Bell.

In April, the Cabinet will decide whether to lower the blood alcohol limit for driving from 0.08 (80mg of alcohol in 100ml of blood) to 0.05mg (50mg alcohol/ 100ml blood) as part of its new road safety strategy, Safer Journeys. There should be no doubt about the decision.

A lower limit means people drink less or not at all before they drive because they don't want to get caught driving drunk. This results in fewer accidents caused by alcohol.

Polls show a majority of New Zealanders favour reducing the limit, but there remains a diminishing minority who oppose the reduction. It's time to weigh their arguments against the evidence.

There is insufficient evidence that driving between 0.05 and 0.08 is unsafe.

A wealth of research has been done (nearly 300 studies in the past 50 years) and the evidence is conclusive. Critical driving abilities such as vision, steering and braking start to become impaired at 0.05 and, by 0.08, a driver is significantly impaired.

We can also look at what happened in eight overseas jurisdictions where the limit was reduced from 0.08 to 0.05. Six of these reported positive road safety results: France, Austria, Queensland, New South Wales, Australian Capital Territory and Japan. In Denmark, there were fewer alcohol-related crashes after the limit reduction, but results were "mixed" because, in a quirk of statistics, more people died in those crashes. In South Australia, results were inconclusive, but the number of drivers caught with high blood alcohol levels did decrease.

When all the international evidence is considered, there is no doubt a lower limit reduces alcohol-impaired driving. This is why a 0.05 limit is standard in most developed countries, and why some, such as Sweden and Norway, have lowered their limits even further.

Lowering the limit would penalise responsible drivers.

A good test of how true this is would be what most people think the limit on drinking before driving should be. The Transport Ministry's Public Attitudes to Road Safety Survey 2009 found that 85 per cent of people preferred a limit of two drinks, which equates to a 0.05 blood- alcohol level. Just 2 per cent said drivers should be permitted four or more drinks, which equates to 0.08 or more.

On present figures, lowering the limit to 0.05 would result in seven to 12 additional drivers in every 1000 being apprehended for drink-driving. However, a lower limit is likely to reduce the number of people opting to drink and drive, so the increase in "responsible drivers" being penalised would be much smaller.

The main problem is recidivist drink- drivers.

Statistically, less than a quarter (24 per cent) of drivers involved in alcohol-related casualty crashes have a drink-driving offence in the five years before their crash, so recidivists are not the main problem. The safety risk needs to be lowered across the general driving population and 0.05 will do that. Recidivists could be further targeted by measures such as compulsory alcohol interlocks on their cars.

Drink-driving is a youth issue.

Although it is true that 15 to 19-year-olds are more likely to be affected by alcohol than other age groups, young drivers are only a part of the drink-drive problem. They make up just 24 per cent of alcohol- affected drivers in crashes.

Most drivers killed have blood alcohol levels higher than 0.08.

That drivers well above 0.08 represent the most killed is not surprising. At 0.15, for example, a driver is more than 180 times more likely to die in a crash. But that does not change the fact that drivers at 0.05-0.08 are also driving with a much higher crash risk. At 0.08 a driver is up to 50 times more likely to be involved in a fatal crash, depending on their age.

International evaluations show that a lower limit is a more effective way to reduce higher-level drink-driving. When the Australian Capital Territory went down to 0.05, drivers caught with blood- alcohol levels between 0.15 and 0.20 fell by 34 per cent. Those above 0.20 declined by 58 per cent. Lowering the limit works because it encourages drivers to keep a better count of their drinks. At 0.05, people are sober enough to decide to either stop drinking or not to drive. Once they reach 0.08, they are less able to make responsible decisions.

Lowering the limit will reduce mobility and social connectedness in rural communities.

At present, most deaths (55 per cent) and serious injuries from drink-drive crashes happen on rural roads. Surely, this would reduce mobility and social connectedness in rural communities more than drinking less before driving. It's much harder in a rural area, for example, to get to a GP or physiotherapist after an accident.

It's also hard to argue that 0.05 would interfere with social drinking. A 0.05 limit equates to about two standard drinks in the first hour and one per hour thereafter. A level of 0.08 equates to six drinks in 90 minutes, which is closer to the definition of binge drinking than social drinking.

The case for retaining the 0.08 limit is pretty hard to sustain. It's time for the Cabinet to stop deliberations and go with the evidence. A drink-drive limit of 0.05 will save an estimated 15 to 33 lives and prevent up to 686 injuries every year. Estimated annual social cost savings are between $111 and $238 million.

It has made for safer journeys overseas. It will do the same thing here.

Ross Bell is director of the New Zealand Drug Foundation