The Automobile Association study of drivers involved in fatal crashes found 79 tested positive for drugs.

Drug-impaired drivers are now involved in more fatal crashes on Kiwi roads than over-the-limit drink-drivers, new research shows.

A study by the Automobile Association (AA) found 79 drivers who were involved in fatal crashes last year later tested positive for drugs, compared to 70 (later updated to 74) who were above the legal alcohol limit or refused to be tested.*

It is thought to be the first time that drugs have overtaken alcohol in this statistic.

BRADEN FASTIER/STUFF Drugs were the suspected cause of a three-vehicle crash in the Tasman district in January. There are now fresh calls for roadside drug testing to be introduced in New Zealand.

In 2013, the number of drug-impaired drivers involved in fatal crashes was just 14, compared with 53 who were intoxicated or avoided tests.

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Drivers who had taken prescription medications above recommended levels, or those known to impair driving, were included in the figures. But the two most commonly-detected drugs (excluding alcohol) were cannabis and methamphetamine.

MIKE CLARE/SUPPLIED AA road safety spokesman Dylan Thomsen said the number of fatal crashes involving methamphetamine had "shot up" in recent years.

AA road safety spokesman Dylan Thomsen said the figures showed drug-driving was an increasing problem in New Zealand, and he believed police should be given the power to carry out roadside saliva-based drug tests.

"Right now, the AA doesn't believe police have the tools they need to get drugged drivers off the road and deter people from doing it."

A member's bill is currently before Parliament, which would give officers the ability to conduct roadside saliva tests for cannabis, MDMA and methamphetamine.

As it stands, for an officer to test a driver for drugs they first need strong cause to suspect drug use. The next step is to take the driver to a station for a "walk-and-turn" test.

"The current system almost needs a driver to be sitting in the car with drugs on the seat next to them to get tested, and the current test takes up a huge amount of an officer's time," Thomsen said.

Saliva-based testing was used in many other countries and it was time New Zealand became one of them, he said.

ROSA WOODS/STUFF Associate Transport Minister Julie Anne Genter said any measures to tackle drug-driving needed to be evidence-based.

Associate Transport Minister Julie Anne Genter said she had asked officials to look at the problem and what other enforcement tactics could be used.

But the jury was still out on whether saliva-based tests were the best option.

"Solutions to tackle drug driving need to be based on evidence and, ultimately, be effective," she said.

STUFF Malcolm Barnett, pictured with wife Sharlene, lost their daughter Krystal in an Upper Hutt road crash caused by a driver high on methamphetamine in September 2005. (File photo)

"I am aware that there remains a number of practical challenges around saliva testing, including the reliability of the testing technology and the time it takes for police to obtain an accurate result."

Genter acknowledged drug-driving was a concern, but said police officers had the authority to order a driver to undergo an impairment test, and follow-up blood test.

"If a driver fails these tests, they can face criminal sanctions."

New Zealand Transport Agency director of safety and environment Harry Wilson said drug-driving was a serious and growing problem both here and globally.

The challenge for policy-makers was to change the often "complacent" attitudes towards driving under the influence of illegal or prescription drugs, he said.

"Many people currently believe they can drive safely on drugs, or that drugs actually make them drive better ... the crash stats prove that isn't the case."

The agency was working to raise awareness of the issue through its road safety advertising campaign, Wilson said.

A police spokesperson said it was not appropriate for to comment on a legislation that was before Parliament.

DRIVERS INVOLVED IN FATAL CRASHES

2017: Drugs proven - 79; above the alcohol limit or test refused - 70 (later updated to 74)

2016: Drugs - 59; alcohol - 67

2015: Drugs - 27; alcohol - 66

2014: Drugs - 14; alcohol - 48

2013: Drugs - 14; alcohol - 53

Note: Some drivers will have tested positive for both drugs and alcohol

* Roger Brooking, from the Drink Driving Intervention Trust, contests the article's premise, because the AA did not include road deaths from alcohol-related accidents where the driver was under the legal limit. NZTA reports that "there were 80 road deaths involving drivers that had a non-zero evidential alcohol reading below the legal limit...". Brooking says: "In other words, 154 deaths were alcohol-related and 79 were drug-related."