It's our silent killer, now the Automobile Association says there needs to be random roadside testing for drugs, similar to alcohol.
The AA's spokesperson, Dylan Thomsen, said drug driving was a silent killer on the country's roads because a lot more drivers involved in fatal crashes were found to have drugs in their system, than people thought.
Blood samples taken from 1046 drivers killed in fatal crashes between 2004 and 2009 found that 1 in 3 had some type of drug in their system, mostly cannabis.
Mr Thomsen said most people were aware of the dangers of drink driving and alcohol but there were a lot of people who didn't see drugs, including cannabis, in the same way.
The Ministry of Health estimates that about 130,000 New Zealanders use cannabis at least once a week and 1 in 3 cannabis users admitted driving stoned in the 2015 cannabis use survey.
He said many drove without realising the risks involved and some even thought they were better drivers when they were stoned, taking risks they otherwise wouldn't.
"The risks are that it slows down your reactions, it makes you more likely to miss seeing something.
"You can become extremely focussed on one thing and not be taking in some of that wider information. So you might be really focussed on controlling your speed, and you aren't seeing that vehicle that's coming from the side."
Mr Thomsen said many people were also ignorant about the risks of combining drugs and alcohol.
"You can have somebody who, they might have a beer, or a wine and they won't drink anymore than that because they don't want to drink and drive. But then they will smoke some of a joint and they don't realise that by combining those two, the impairing effect it has multiplies massively.
"So any combination of alcohol with an illegal drug, or even with prescription medication. So people taking different types of medicines and then can have a drink and think, well I'm well under the drink drive limit.
"But it's changing the way you think about whether you're in a fit state to drive," he said.
Mr Thomsen said more and more countries had introduced road side drug testing, including Australia and the United Kingdom.
"Rather than a breath test for alcohol you've got a saliva based test, where they basically take a swab from inside your mouth and are able to check for a range of drugs.
"The AA wants to see that introduced in New Zealand," he said.
Every state in Australia now has roadside drug testing, which test for cannabis, ecstasy and methamphetamine. Most are doing more than 50,000 drug tests a year.
"Now in a lot of states they are catching more people for drugged driving than drunk-driving. It's a major issue on the roads."
He said the vast majority of people in New Zealand didn't drink and drive and the country needed to work towards getting to a similar place with drugs.