Pubdate: Wed, 09 Nov 2016
Source: Globe and Mail (Canada)
Copyright: 2016 The Globe and Mail Company
Contact:  http://www.theglobeandmail.com/
Details: http://www.mapinc.org/media/168
Author: Mike Hager
Page: S1

POT BAN ON DRIVERS WON'T WORK, EXPERTS SAY

It would be unrealistic to bar drivers from having any trace of
marijuana in their system when it becomes legal in Canada, as B.C. has
suggested, because the drug can be detected long after a person is
impaired, public health experts say.

The federal government's task force on the future of cannabis
legalization has highlighted impaired driving as one of the core
issues it must address before making its recommendations by the end of
this month.

It's an issue that several provinces have also raised as a major
concern. Most recently, British Columbia's Solicitor-General, Mike
Morris, told the BC Liberal Party's convention on the weekend that he
favours such a zero-tolerance policy when it comes to drivers and
cannabis. Mr. Morris noted that Australia has implemented such a policy.

But M.J. Milloy, an infectious disease epidemiologist who is studying
the therapeutic effects of marijuana at the B.C. Centre for Excellence
in HIV/AIDS, said enforcing a zero-tolerance approach would be
problematic because roadside testing could capture traces of
tetrahydrocannabinol (THC), the psychoactive compound in cannabis,
long after the driver feels any sort of high.

"THC sticks around for a long time," he said, adding that blood tests
can reveal traces of the compound two weeks after marijuana is consumed.

Instead, Dr. Milloy said, the federal government should invest in
researching how and to what degree cannabis impairs drivers. Then
policy makers can create an objective limit of THC impairment, he
said. The best option for testing that limit may be by swabbing
someone's saliva, which could reveal use of the substance hours - not
days - beforehand, he added.

Still, he said, Washington and Colorado's established limits of five
nanograms of THC per millilitre of blood are arbitrary because
different people can metabolize the drug to widely varying degrees,
depending on their body type and history of using cannabis.

There are other barriers to a testing and enforcement regime. Roadside
cannabis tests are still in their pilot stages, and researchers are
trying to determine how, and at what level, marijuana affects drivers.
The Toronto-based Centre for Addiction and Mental Health could release
results as early as next month on its three-year study of how
marijuana impairs one's driving ability.

David Hammond, an associate professor of public health at the
University of Waterloo, said it is accepted that marijuana can impair
one's co-ordination, ability to pay attention as well as reaction
time, but more research is needed to assess the role marijuana use
plays in fatal traffic accidents. "There's no evidence that it's more
dangerous [than alcohol] and requires stiffer penalties," Prof.
Hammond said. "If a jurisdiction wants to have stiffer penalties and
have zero tolerance, that's fine, but I think they should be
consistent across substances."

The federal task force on legalization reported that 97 per cent of
impaired-driving incidents reported by police in 2013 involved
alcohol, while only 3 per cent involved drugs, including cannabis.

Prof. Hammond said that having different impairment standards creates
the risk of a cultural bias that penalizes those who prefer a toke
over those who like a cocktail, the latter of which has been
normalized in Canadian society - especially among wealthier citizens.

An August, 2012, Saskatchewan Provincial Court ruling illustrates how
difficult it can be for police to get cannabis-impaired driving
charges to stick under the current system of enforcement.

In that case, a judge ruled that police at a roadside check could not
prove a woman was impaired from a joint she admitted to smoking
21⁄2 hours earlier. That was despite her failing several field
sobriety tests - such as walking in a straight line and touching her
nose - and being given a blood test at the police station that was
positive for THC. The judge stated that there was no doubt the accused
had used the drug before getting in her car, but there was no proof
that it negatively affected her performance behind the wheel.

"These observations and tests do not assist me in determining if her
consumption of marijuana was such that her ability to drive a motor
vehicle was impaired at the time she was observed driving," the judge
ruled.
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