Pubdate: Wed, 04 May 2005
Source: New Zealand Herald (New Zealand)
Copyright: 2005 New Zealand Herald
Contact:  http://www.nzherald.co.nz/
Details: http://www.mapinc.org/media/300
Author: Martin Johnston
Bookmark: http://www.mapinc.org/find?224 (Cannabis and Driving)
Bookmark: http://www.mapinc.org/testing.htm (Drug Testing)

NEW ZEALAND: STUDY LINKS CANNABIS AND CRASHES

Study Links Cannabis and Crashes

Drivers who regularly use cannabis are at high risk of causing a
serious crash, but not because they have just smoked a joint, a study
has found.

The Auckland University study of more than 1000 drivers found that
habitual users - who on average smoked at least once a week - had a
nearly 10-fold higher risk of having a serious crash.

Drivers who had smoked a joint within the last three hours initially
appeared to be at increased risk too, but this link disappeared when
factors such as their alcohol consumption and driving speed were taken
into account.

The researchers, whose paper has been published in the British journal
Addiction, do not know why habitual users are at increased risk. But
they do advise against roadside testing of drivers for cannabis use
because of the small numbers who have just had a toke and the virtual
absence of a link between that and serious crashes.

Only 0.5 per cent of drivers in the randomly selected, roadside arm of
the study had smoked within the previous three hours, though most of
those who had were habitual users.

The paper says targeting groups in the population at high risk for
cannabis use may therefore be more cost-effective than roadside testing.

The Government is keen to introduce roadside drug testing if overseas
research produces a reliable system, but acknowledges the
difficulties.

"There is some road-testing in Australia in one or two states,"
Associate Health Minister Jim Anderton said last night. "The police
here have been evaluating their results and running some trials.

"The problem we've got is that there's a multiplicity of drugs ... so
you would need to have different tests."

The Auckland University researchers interviewed the drivers of 571
vehicles involved in crashes in which one or more occupants was
hospitalised or killed and those of 588 randomly selected cars they
flagged down in the Auckland region.

Ten per cent of the serious-crash drivers were habitual cannabis
users, compared with 0.9 per cent of the other group.

The journal paper suggested it was unlikely that the increased crash
risk among habitual users was due to brain damage from the drug.

"It's much more likely to be things about habitual marijuana smokers,
the way they drive, the type of people they are, than anything else,
but we don't know," said one of the researchers, Dr Jennie Connor.
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MAP posted-by: Larry Seguin