One in five Kiwis think they can have three or more alcoholic drinks and drive - research

One in five New Zealanders believes they can have three or more alcoholic drinks and still drive, according to new research.

The research, commissioned by DB Breweries, surveyed 500 people over the age of 18 who drank alcohol. It found that New Zealand drivers have a significant knowledge gap when it comes to the laws around drinking and driving.

While 73 percent of people said they understand the drink driving laws, only 22 percent know the official blood alcohol content limit.

Blood alcohol content is used to determine whether someone is under the influence of alcohol. The alcohol limit for drivers over 20 years old is 50mg of alcohol per 100ml of blood.

However, according to the research, 20 percent of drivers think they can have three or more drinks and still get behind the wheel.

It also found people who drink on average one to three drinks per week believe they can safely drink 2.8 drinks and then drive.

This is compared to non-drinking drivers who think they can safely drink 1.8 drinks and be ok to drive.

Another 20 percent have driven within two hours of drinking in the last 14 days.

Managing director at DB Breweries, Peter Simons, said most people focus on how many drinks they have and not the actual units.

This can be inaccurate because there is a difference between a 'standard drink' and a 330ml bottle of beer, which generally contains more than one standard drink per serving.

Simons said basing it on the number of drinks is problematic because it's very subjective and varies from person to person.

"So many factors contribute to an individual's blood alcohol count that it is impossible to base your choice to drive on the number of drinks you consume. Because of this ambiguity, the safest option is always not to drink at all when driving.

Students Against Dangerous Driving (SADD) national manager Donna Govorko told the AM Show having a zero alcohol limit would be the best way to remove confusion. 

"Why do you need to drink and then drive? There are lots of other options."

Govorko said the previous legal alcohol limit was way too high and people haven't adjusted to the new law. 

"It took way to long to bring it down. I think the older generation still think they can drink maybe three, four or even five [drinks]."

She said most people are also unaware of how many standard drinks are in an average bottle of wine or beer. 

An average bottle of wine has just over 8 standard drinks while a 440ml can of 4.2 percent beer has 1.5. 

As a former police officer, she said unfortunately the confusion over the legal limit didn't come as a shock. 

"I used to see the effects of people thinking they were quite able to get into a car and drive when they were quite substantially over the limit, it just didn't register to them."

She said people are still under the belief that if they have only had "a couple of drinks", they are fine". But Govorko said it is difficult to calculate because there are so many variables. 

"Different factors affect you: your weight, your gender, how hydrated you are, what you have actually had to drink. If you have two light beers and then two 5 percent beers and it is totally different."

A police spokesperson said it's important to plan ahead when socialising, make alternative arrangements if circumstances change and if drinking, don't drive.

"It's never worth the risk to get behind the wheel or on a bike when you've been drinking and could be impaired."