Re: MAPS: marijuana and impairment.

[John Lucas <jlucas@xxxxxxxxxxx>]

I believe the report to which you refer was actually done by the Federal
Government.  This is from the Cal NORML March 1994 bulletin.

Hope this helps.
John Lucas
jlucas@xxxxxxxxxxx
------------------

A newly released National Highway Transportation Safety Administration study
indicates that alcohol is by far the leading cause of drug-related traffic
fatalities, while marijuana poses negligible danger except when combined with
alcohol.
 The study, the most comprehensive drug accident survey to date, is dated October
1992, but is only now being released. A researcher familiar with the project says
this is because it contradicts the government's official anti-drug line that
illicit drugs are a major public safety hazard.
 The study investigated blood samples from 1882 drivers killed in car, truck and
motorcycle accidents in seven states during 1990 - 91. Alcohol was found in 51.5%
of the specimens. Just 17.8% showed traces of other drugs; marijuana was a
distant second to alcohol at 6.7%, followed by cocaine (5.3%), benzodiazepine
tranquillizers (2.9%) and amphetamine (1.9%). Two-thirds of marijuana- and
other-drug-using drivers were also positive for alcohol.
 The report concluded that alcohol was by far the "dominant problem" in
drug-related accidents. A responsibility analysis showed that alcohol-using
drivers were conspicuously culpable in fatal accidents, especially at high blood
concentrations or in combination with other drugs, including marijuana. However,
those who used marijuana alone were found to be if anything less culpable than
non-drug-users. The report concluded, "there was no indication that marijuana by
itself was a cause of fatal accidents."
 Although California NORML's "Health Tips for Marijuana Smokers," by California
NORML coordinator Dale Gieringer, lists accidents and respiratory disease due to
smoking as the two leading health hazards of marijuana, these findings are
consistent with other studies, which have generally found that marijuana is
rarely involved in driving accidents except when combined with alcohol.
 The NHTSA report, "The Incidence and Role of Drugs in Fatally Injured Drivers,"
by K.W. Terhune, et al. of the Calspan Corp. Accident Research Group in Buffalo,
NY (Report # DOT-HS-808-065) is available from the National Technical Information
Service, Springfield VA 22161.
---------------------------------
March 1994

The second recently released NHTSA report, "Marijuana and Actual Driving
Performance" (Robbe & O'Hanlon, November 1993), was conducted in The Netherlands,
where the government actually promulgates harm reduction-based drug policies.
This report was comprised of the results of three controlled experiments in which
subjects consumed various dosages of marijuana and then drove in freeway- and
city-driving conditions. The performances of marijuana consumers were then
compared with the performances of subjects under the influence of alcohol.

The report concluded:

"... marijuana, when taken alone, produces a moderate degree of driving
impairment which is related to the consumed THC dose. The impairment manifests
itself mainly in the ability to maintain a steady lateral position on the road,
but its magnitude is not exceptional in comparison with changes produced by many
medicinal drugs and alcohol. Drivers under the influence of marijuana retain
insight in their performance and will compensate where they can, for example, by
slowing down or increasing effort. As a consequence, THC's adverse effects on
driving performance appear relatively small." (abstract page)

 Moreover, the authors summarized, "... both direct and indirect evidence
converge on the conclusion that THC's effects after doses up to [the maximum
level used in the study, which had been determined to be the maximum dosage
marijuana consumers typically ingest to get "high"] never exceed alcohol's at
[blood alcohol concentrations of .08%]." (This concentration is less than or
equal to the legal limit for driving in most states.) (p. 105)


Cyrus McCandless wrote:

> I had heard a couple of years ago that two major insurance companies did a
> very large study to determine whether marijuana users were an
> insurance risk.  They used records of blood samples taken from people
> involved in accidents, and found that people with THC in their blood were
> actually less likely to be the *cause* of an accident, although it says
> nothing about whether they would be more likely to be involved in one.
>
> Can someone on this list confirm/provide a reference for this, and maybe
> a place to obtain the report?
>
> Cyrus
>
> On Fri, 30 Apr 1999, John Baltic wrote:
>
> > A question on marijuana impairment, mostly as it relates to driving an
> > automobile.  Can it be measured?  Is there a test?
> >
> > With alchohol we measure the amount in the blood or breath and set a limit.
> > How might impairment be tested in subjects who may have smoked marijuna?
> >
> > The other questions are, of course, does marijuna use cause any impairment
> > of functioning?   Maybe marijuna users are better drivers than nonusers,
> > right?  Maybe it enhances functioning, or some functioning, up to a point.
> >
> >
> >
> >
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