Pubdate: Fri, 03 Jun 2016
Source: Province, The (CN BC)
Page: 11
Copyright: 2016 Postmedia Network Inc.
Author: David Booth


BEHIND THE WHEEL: Recent studies indicate smoking marijuana far less 
dangerous than drinking booze

The National Post recently scandalized its famously conservative 
readers with a headline claiming that "about half of Canadians who 
drive while high insist pot doesn't impair them."

The article - When is stoned too stoned? - further sensationalized 
the "crisis" by noting: "nothing would make (20 per cent of those 
surveyed) stop driving while stoned."

With the Trudeau government poised to legalize marijuana, it was 
enough to send neo-cons into paroxysms of paranoia, fearing our roads 
would be turned into killing fields by the demon weed.

It didn't help matters that CNN Money also ramped up the hype by 
noting the number of fatalities involving drivers who had consumed 
marijuana had doubled since Washington state legalized pot for 
recreational consumption. About time, then, that many jurisdictions 
are quickly instituting alcohol-like limits to the THC content one 
can have in the bloodstream and still be allowed to drive.

The only problem is that the stoners might have it right.

Marijuana, by most measures, is not in any way the scourge that 
alcohol is. We may indeed be perfectly competent to drive while 
"baked." At the very least, the methodology currently being employed 
to identify those impaired by excessive THC consumption may be 
grossly ineffective and, at worst, prejudicial.

The problem with trying to weed out those too toasted to drive is 
two-fold, namely: the testing is faulty and, perhaps more surprising, 
the evidence that getting high will result in more automobile 
accidents - as it does so conclusively for alcohol - is very thin indeed.

For one thing, the current testing regime is flawed. Essentially 
following the protocol employed to measure alcohol impairment, 
current restrictions are based on limiting the amount of 
Tetrahydrocannabinol (THC) in your bloodstream while driving. Besides 
the compete lack of consensus on how much THC is too much (current 
limits under discussion range from one nanogram per millilitre of 
blood to five ng) there doesn't seem to be any direct correlation 
between increased levels of THC in the blood and traffic fatalities.

Even Peter Kissinger, chief executive of the American Motorists 
Association, one of the organizations for marijuana prohibition, says 
"It's simply not possible today to determine whether a driver is 
impaired based solely on the amount of the drug in their body."

The problem, say medical experts, is that THC, unlike alcohol, can 
stay in your bloodstream for weeks, long after any effects have worn 
off. Jolene Forman, a staff lawyer for the Drug Policy Alliance, a 
drug-reform advocacy group, told the New York Times that using 
roadside THC blood tests to prove impairment is "equivalent to a test 
that shows that you had a glass of wine three nights prior." Indeed, 
the main reason to implement a blood test for THC content would seem 
to be that constabularies find an easily quantified objective 
restriction more convenient than a subjective test for impairment.

And, it is in the area of just how "impaired" one is that the 
reasoning behind marijuana restrictions gets even murkier.

While there is little doubt that THC somewhat impairs certain motor 
skills - for instance, compromising the ability to steadily walk 
heel-to-toe - numerous driver simulation studies have shown that 
those driving under the influence of marijuana, in complete contrast 
to the aggressive driving habits of those under the influence of 
alcohol, compensate by driving more cautiously.

The University of Iowa Carver College of Medicine, for instance, 
found that, after smoking a "marijuana cigarette," 85 subjects in a 
double-blind study performed virtually the same after smoking 
cannabis as they did sober, with "no differences found during the 
baseline driving segment (and the) collision-avoidance scenarios."

Indeed, a Canadian senate study showed that while "evidence of 
impairment from the consumption of cannabis has been reported by 
studies using laboratory tests, driving simulators and on-road 
observation" these results "do not necessarily reflect 'impairment' 
in terms of performance effectiveness, since few studies report 
increased accident risk."

And no less than the U.S. National Highway Traffic Safety 
Administration concluded that once you factor out age, gender, race 
and alcohol use, "drivers who tested positive for marijuana were no 
more likely to crash" than those who were stone-cold sober. The one 
notable exception is the combination of alcohol and cannabis, which 
seems to exacerbate the effect of both.

That senate study suggested lowering the alcohol limit to 40 
milligrams of alcohol - as opposed to the current limit of 80 mg - 
per 100 millilitres of blood, in the "presence of other drugs, 
especially ... cannabis."

Even more telling is that, according to a University of Chicago 
study, marijuana use may reduce accidents. According to Medical 
Marijuana Laws, Traffic Fatalities, and Alcohol Consumption, the 19 
states that have legalized marijuana saw "an eight to 11 per cent 
decrease in traffic fatalities" in the first full year after the 
medical marijuana laws were passed.

The hypothesis is that drivers are substituting marijuana for 
alcohol, Ottawa's Traffic Injury Research Association theorizing that 
"these sharp declines may be due to the decreased number of 
alcohol-impaired drivers on the road as a result of the legalization 
of medical marijuana." Whatever the case, it turns out the reason 
more Washingtonians are dying in car accidents with THC in their 
bloodstream isn't so much that pot consumption is causing more 
accidents but simply that more people are smoking pot.

Nonetheless, it's not difficult to see there's still a cautionary 
note of ambivalence in the medical/ safety community about 
disregarding the potential dangers of marijuana consumption on driving safety.

Despite (at least) some evidence that smoking marijuana presents 
little additional risk of being in an accident, no one wants to sound 

Indeed, reading between the lines in these numerous studies, one gets 
the impression that most of the authors don't seem so much worried 
about the effects of marijuana while driving as the blowback from not 
being worried about the effects of marijuana while driving.

Note: This article in no way promotes the consumption of marijuana 
before, during or, for that matter, after driving an automobile. It 
does not, in fact, promote the use of cannabis at any time. Indeed, 
although the author readily admits to misspending his youth (back in 
the days when Thai Stick ruled the THC world), except for a weekend 
of reminiscence in Amsterdam some 20 years ago, absolutely no illicit 
substances have found their way into his bloodstream since graduating 
from university in 1983.
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MAP posted-by: Jay Bergstrom