Drink-driving limit: Too many people wrongly believe three drinks is okay

Motorists are still confused about "ambiguous" drink-drive laws, with many believing they are fine to get behind the wheel after three drinks.

New research released today shows the average motorist has a significant knowledge gap when it comes to the laws around drinking and driving.

While nearly three-quarters of motorists are confident they understand the rules, only 22 per cent actually know the correct legal adult limit - and 20 per cent believe they can have three or more drinks before driving.

The findings suggest people are basing how much they drink around the number of drinks they think they can have, rather than blood alcohol content which can vary greatly from person to person.

Alcohol contributes to around 30 per cent of New Zealand's fatal road crashes. About 1100 people have been killed and a further 5300 injured in drink-driving crashes during the past 10 years.

The current limit was implemented by the Land Transport Amendment Act in 2014, lowering the drink-driving cap for adult drivers aged over 20 from 400mcg to 250mcg of alcohol per litre of breath.

AA road safety spokesman Dylan Thomsen said the current approach to preventing drink driving was not working.

"Even with the reduction of the alcohol limit in 2014, we haven't seen the levels of people driving under the influence of alcohol come down by much, and now it's plateauing.

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"We need to be doing more to police alcohol testing and checkpoints – without that more of these people will think they're more likely to get away with drink-driving."

Thomsen said part of the problem was that the current system was "a bit ambiguous".

"The rule of thumb is you should be okay if you don't have more than two standard drinks. But people need to be more aware of what a standard drink is. There are so many subjective aspects to think of with this too, like people's build, or have you eaten?"

The research was conducted by DB Breweries and managing director Peter Simons said it confirmed the public largely misunderstood official blood-alcohol content guidelines.

"This research has shown us that instead of thinking about blood-alcohol content, people find it easier to consider the 'number of drinks' they are allowed before they get behind the wheel. This is a problem because it is such a subjective measure."

Leah Abrams, founder of a charity to help the victim of drink-driving accidents, was hit by a driver just over the breath alcohol limit in 2015. Photo / Supplied

According to the Institute of Environmental Science and Research, most adults are likely to be able to drink two standard drinks over two hours and remain under the limit.

However, research by the National Institute for Health and Clinical Excellence shows that drivers with 250mcg of alcohol per litre of breath are three times more likely to die in a crash, because even small amounts of alcohol affect drivers' reaction times, judgment and co-ordination.

The scene of a crash in which Leah Abrams was hit by a driver just over the breath alcohol limit in 2015. Photo / Supplied

Auckland woman Leah Abrams was critically injured by a drink-driver in Mt Eden in 2015.

The 44-year-old, who set up an anti-drink-driving campaign, No One Ever Stands Alone, believes there should be a zero-alcohol policy for all drivers given the ambiguity of the current rules.

"After I was hit by a driver under the influence of drink, I spent a week in hospital and the rest of 2016 recovering from my injuries," she said.

"The driver who hit me was not wildly over the limit, he had consumed 400mcg of alcohol, which is just on the cusp of what is currently legal in New Zealand.

"This shows that although he was at the right end of the scale, he had still consumed enough to be impaired enough to cause my crash and change my life forever.

"The mentality has to change from sticking within limits to just not drinking at all when you're going to drive. You're putting others in peril and it's just not worth it."

Road safety charity Brake is also calling on motorists to give alcohol a swerve when it comes to driving.

Caroline Perry, the New Zealand director of Brake, said it was extremely risky getting behind the wheel after a drink so this new research around people's attitudes were very concerning.

"Even if you feel okay after a drink, the reality is that if you get behind the wheel you're putting yourself and others in needless danger. The only safe amount of alcohol to consume if you're driving is none."

Nearly 19,000 people were charged last year for 'driving under the influence' offences. Photo / file

Sandra Venables, Assistant Commissioner for Road Policing, echoed the comments.

"Our message is always if you're drinking, don't drive.

"We want people to be safe and responsible; to plan ahead when they're socialising, or to make alternative arrangements if circumstances change while you're out. It's never worth the risk to get behind the wheel or on a bike when you've been drinking and could be impaired."

Drivers caught with breath-alcohol levels of between 251mcg and 400mcg receive a $200 fine and 50 demerit points but avoid a conviction. Anybody caught driving with a level of more than 400mcg goes to court.

Ministry of Justice figures show the number of drink-driving convictions has risen from 17,634 in 2016/17 to 18,463 in 2018/19.

DRINK DRIVING

• Alcohol contributes to around 30% of New Zealand's fatal road crashes.

• Over the past 10 years, fatal crashes caused by drink-driving have claimed the lives of around 1100 people in New Zealand and caused serious injuries to a further 5300.

• In 2018/19 there were 18,463 charges for 'driving under the influence' offences in New Zealand, with 94% of charges convicted.

• Of those convicted, 76% were male and 23% were female.

• 427 Kiwis were imprisoned in 2018/19 for driving under the influence.