CANNABIS GROUP ATTACKS DRIVER TESTS

A pro-cannabis lobby group says a proposed trial to test drivers for drug
use could be too subjective to be accurate.

Police booze bus staff nationwide will be trained this month to identify
drivers on drugs, in preparation for a three to six-month trial, expected
before June. Northland is one of the likely testing spots.

Staff will learn to spot a driver on drugs by physical indicators and tests,
such as requiring the driver to stand on one leg. Police would then require
the motorist to take an evidential blood test.

While the regions for the trial have yet to be decided, national police road
and safety manager Superintendent Steve Fitzgerald has said that Northland
is a likely option.

National Organisation for Reform of Marijuana Laws (NORML) spokesman Chris
Fowlie said Norml did not support people driving while impaired in any way,
but was concerned with how police were planning to determine what
constituted "impaired".

"All the Government is preparing is a subjective test where an officer will
decide on the spot whether someone is affected by drugs based on dilated
pupils, slurred speech and their ability to walk a straight line. Our big
concern is that there will be potentially biased officers taking a very
subjective assessment of a driver."

He said that while blood-alcohol readings could be very accurate follow-ups
to breath-testing in the case of alcohol impairment, the high-inducing agent
in cannabis, tetrahydrocannabinol (THC), broke down into non-psychoactive
metabolites (which do not cause impairment) very quickly.

These could be stored in the body for up to a month.

"It [the test] is useless for measuring impairment. Clearly people would not
be impaired a month after smoking a joint," Mr Fowlie said.

In contrast, harder drugs such as methamphetamine were harder to detect both
subjectively and in blood tests.

"The methodology's ill-conceived and will see a lot of people of no danger
to road users potentially being arrested."

Overseas studies showed that cannabis could affect reaction times and the
ability to maintain a steady, straight line. However, people concentrated
more on their driving when stoned and were much less likely to take risks
when driving, Mr Fowlie said.

Mr Fitzgerald has said the "field impairment tests" were designed by
neurologists, and properly trained staff would be 95 per cent accurate.

Under the Land Transport Act it is an offence to drive under the influence
of drugs to the extent of being "incapable of having proper control of the
vehicle".

There are no defined thresholds for the level of drugs which would render a
driver "incapable" and a charging threshold has yet to be established.

"The trial is simply the first step for us to say technology is moving on
and the legislation is likely to change, so it's about time we make a move
to get some expertise on the subject."

Northland road policing manager Inspector Rex Knight said driver
drug-testing might take two years to be instituted fully but the trial was a
positive step.

Police estimate that up to 16 per cent of drivers killed on New Zealand
roads have been under the influence of drugs.