Pubdate: Thu, 21 Jul 2011
Source: Vancouver Sun (CN BC)
Copyright: 2011 The Vancouver Sun
Author: Pamela Fayerman, Vancouver Sun


Hospitals to Test Injured Drivers' Blood Without Their

Injured drivers taken to B. C. hospitals over the next five years will
help answer the question: Do those who are high on marijuana cause
more crashes than sober drivers?

In the marijuana-impairment study -- the first of its kind in Canada --
blood will be collected from injured drivers without their permission.
Since the data is collected anonymously and not used to pursue legal
charges, researchers don't have to seek approval from drivers to
analyze their blood under the ethics-approved terms of the study.

Blood is drawn for treatment of any injuries and the excess amount is
then analyzed. The sample is assigned a code that is not shared with
police, and the resulting data is then linked to police accident
reports to eventually show researchers if cannabis contributed to the

A recent random sampling of B. C. drivers showed that 10 per cent were
impaired by alcohol and 7.2 per cent by drugs, usually marijuana or
cocaine. After alcohol, cannabis is the most widely used intoxicating
substance in the world. In the random sampling, it accounted for about
two-thirds of the drugs detected at the police roadside stops,
followed by cocaine.

Concentrations of THC, the active ingredient in cannabis, will be
measured in the new marijuana study. It will be led by Dr. Jeffrey
Brubacher, an emergency doctor at Vancouver General Hospital.

Many marijuana users think it's less hazardous because cannabis tends
to make people drive more slowly and less aggressively than, say,
drivers who are drunk, according to studies.

At the same time, drivers high on marijuana have a harder time staying
within lanes and their reflexes are slower, which means they are more
likely to crash into obstacles that suddenly appear. On the other
hand, " cannabis users tend to overestimate their impairment whereas
people who used alcohol underestimate theirs," Brubacher stated in an
explanation of his study in the B. C. Medical Journal.

Brubacher said data on the first 100 injured drivers have already been
collected for the study, which aims to include information on 3,000
crashinvolved drivers at five B. C. hospitals.

THC levels in blood -- which are measurable no matter how the cannabis
is consumed ( smoked, sprayed, drunk or eaten) -- yield a blood THC
concentration considered more accurate than THC metabolites in urine.
Brubacher said urine metabolites remain active for days after cannabis
exposure, even though impairment typically lasts less than four hours.

" Our primary objective is to determine whether injured drivers who
used cannabis before a motor vehicle accident are more likely to have
caused the crash than those who did not," said Brubacher, adding that
the number of crashes caused by impaired drivers will be compared to a
control group of drivers who were found to be not culpable.

The ultimate goal of the $ 1-million study, funded by the federal
Canadian Institutes of Health Research, is to help traffic-safety
experts develop safer driving policies. It is possible, for example,
that the study might show whether there should be a legal cutoff level
for THC blood concentration, just as there is for alcohol. The study
results should also help inform the debate around whether marijuana
possession should be decriminalized.

When it comes to drug-impaired drivers, current practice is for police
to do a roadside sobriety test if they have suspicions. If the driver
fails the initial observational tests ( walking a straight line, etc.)
then the driver must accompany the officer to a police station for
further examination by a specially trained drug recognition expert.
Drivers may be ordered to submit blood, saliva or urine samples, or
face a fine for refusing to comply.

While there have been some surveys showing that drivers impaired by
cannabis were nearly twice as likely to crash, Brubacher and his
co-investigators are using a similar " culpability" study design as
was used in studies in Australia and France, linking data from injured
drivers to police reports to show who caused the accident and their
level of impairment.

Those studies had a few drawbacks, however, including a cumbersome
process in which the drawing of blood was delayed about three hours
from the time of the crash.

" We anticipate that our data will provide a more accurate reflection
of true THC levels at the time of crash," Brubacher said, noting that
in a pilot project, the average time from crash to blood draw was 53

RCMP Supt. Norm Gaumont said he's pleased the study is being conducted
because there is little research on the effects of drug-impaired
driving compared to the evidence about the dangers of drunk driving.
Gaumont, who heads traffic services in B. C., said there is urgency to
get the type of data in the study because of a steady increase in the
number of deaths caused by drug-impaired drivers. At last count, B. C.
coroners showed there were 62 deaths ( out of 374 in 2008)
attributable to drugimpaired drivers.

" Drug impairment is becoming a bigger and bigger problem. We've done
a good job educating people about drunk driving, but [ offered] very
little on drugs. So certainly this study will be a benefit," Gaumont
said. He added that B. C. lawenforcement authorities are monitoring
studies in Europe and Australia, where police are experimenting with
roadside saliva tests that can yield instant information about what
drugs drivers have used, and their level of impairment.
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