Drugs deadly on our roads: study

Cannabis: Found to be a major contributor to road deaths.

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Drugs are as big a menace on our roads as alcohol, a new study has found.

The blood of more than 1000 drivers killed on our roads in the past five years was tested for the police by Dr Helen Poulsen from Environment Science and Research (ESR).

The 1046 drivers tested represented 89% of those killed on the roads between 2004-2009 – and almost half of them returned positive results for alcohol and drugs. The results of the "Alcohol and other drug use in New Zealand drivers 2004-2009" project could undermine the country's focus on drink-driving because cannabis was also a major contributor to road deaths.

Of the 500 drivers who had used alcohol, cannabis or a combination of both, Poulsen's report found 135 drivers used alcohol alone, 96 used only cannabis, 142 used both, and 127 used a combination of drugs.

As a result the Automobile Association is calling for people processed for drink-driving to be assessed for alcohol dependency, and for roadside saliva tests to detect drugs, including cannabis and methamphetamine – commonly known as P – as is done in some Australian states.

AA motoring affairs general manager Mike Noon said the debate on whether to lower New Zealand's blood-alcohol content level from 80mg to 50mg per 100ml of blood did not recognise that the worst-impaired drivers were going undetected.

"These results show focusing on alcohol and drink-driving won't address the problem of impaired drivers on our roads. The report says when alcohol and drugs are used together, the effects are likely to be greater than when just one is used.

"People with drugs in their system might pass an alcohol roadside breath test and not be suspected for drugs, but their driving may be seriously impaired," he said.

The report proved better drug testing of drivers was needed because a third of tested drivers who died over the past five years had taken drugs.

He said the findings also threw up useful data on blood-alcohol content levels. The study showed 21 of 1046 deceased drivers had blood-alcohol levels between 50mg and 80mg. Only 10 of them used alcohol alone, while the other 11 also used an impairing drug, he said.

For drivers with levels above the current 80mg limit, 27% were between 81 and 160, 35% between 161 and 240 and 15% had levels over 240mg. "There's all this focus on lowering the limit but the drivers who are dying are very drunk," Noon said.

Last month Transport Minister Steven Joyce was widely criticised when National would not lower the limit for those over 20, saying more research was needed.

- © Fairfax NZ News