Studies Show Traffic Deaths Won't Rise as States Legalize Marijuana
As states liberalize their marijuana laws, public officials and safety
advocates worry that more drivers high on pot will lead to a big
increase in traffic deaths. Researchers, though, are divided on the
Studies of marijuana's effects show that the drug can
slow decision-making, decrease peripheral vision and impede
multitasking, all of which are critical driving skills. But unlike with
alcohol, drivers high on pot tend to be aware that they are impaired and
try to compensate by driving slowly, avoiding risky actions such as
passing other cars, and allowing extra room between vehicles.
the other hand, combining marijuana with alcohol appears to eliminate
the pot smoker's exaggerated caution and seems to increase driving
impairment beyond the effects of either substance alone.
and Washington are the only states that allow retail sales of marijuana
for recreational use. Efforts to legalize recreational marijuana are
underway in Alaska, Massachusetts, New York, Oregon and the District of
Columbia. Twenty-three states and the nation's capital permit marijuana
use for medical purposes. It is illegal in all states to drive while impaired by marijuana.
Washington and Montana have set an intoxication threshold of 5 parts
per billion of THC, the psychoactive ingredient in pot, in the blood. A
few other states have set intoxication thresholds, but most have not set
a specific level. In Washington, there was a jump of nearly 25 percent
in drivers testing positive for marijuana in 2013 - the first full year
after legalization - but no corresponding increase in car accidents or
What worries highway safety experts are cases like
that of New York teenager Joseph Beer, who in October 2012 smoked
marijuana, climbed into a Subaru Impreza with four friends and drove
more than 100 mph before losing control. The car crashed into trees with
such force that the vehicle split in half, killing his friends.
Beer pleaded guilty to aggravated vehicular homicide and was sentenced last week to 5 years to 15 years in prison.
prosecutor blamed the crash on "speed and weed," but a Yale University
Medical School expert on drug abuse who testified at the trial said
studies of marijuana and crash risk are "highly inconclusive." Some
studies show a two- or three-fold increase, while others show none, said
Dr. Mehmet Sofuoglu. Some studies even showed less risk if someone was
marijuana positive, he testified.
Teenage boys and young men are
the most likely drivers to smoke pot and the most likely drivers to have
an accident regardless of whether they're high, he said.
In 2012, just over
10 percent of high school seniors said they had smoked pot before
driving at least once in the prior two weeks, according to Monitoring
the Future, an annual University of Michigan survey of 50,000 middle and
high school students. Nearly twice as many male students as female
students said they had smoked marijuana before driving.
roadside survey by the National Highway Traffic Safety Administration in
2007 found 8.6 percent of drivers tested positive for THC, but it's not
possible to say how many were high at the time because drivers were
tested only for the presence of drugs, not the amount.
marijuana high generally peaks within a half hour and dissipates within
three hours, but THC can linger for days in the bodies of habitual
Inexperienced pot smokers are likely to be more impaired
than habitual smokers, who develop a tolerance. Some studies show
virtually no driving impairment in habitual smokers.
Two recent studies that used similar data to assess crash risk came to opposite conclusions.
University researchers compared drivers who tested positive for
marijuana in the roadside survey with state drug and alcohol tests of
drivers killed in crashes. They found that marijuana alone increased the
likelihood of being involved in a fatal crash by 80 percent.
because the study included states where not all drivers are tested for
alcohol and drugs, a majority of drivers in fatal crashes were excluded,
possibly skewing the results. Also, the use of urine tests rather than
blood tests in some cases may overestimate marijuana use and impairment.
Pacific Institute for Research and Evaluation study used the roadside
survey and data from nine states that test more than 80 percent of
drivers killed in crashes. When adjusted for alcohol and driver
demographics, the study found that otherwise sober drivers who tested
positive for marijuana were slightly less likely to have been involved
in a crash than drivers who tested negative for all drugs.
states do not test drivers involved in a fatal crash for drugs unless
there is reason to suspect impairment. Even if impairment is suspected,
if the driver tests positive for alcohol, there may be no further
testing because alcohol alone may be enough to bring criminal charges.
Testing procedures also vary from state to state.
If you or a loved one is in a bind as a result of a DUI, immediately contact a Seattle DUI attorney. A DUI lawyer
is not going to judge you, and understands that everyone makes
mistakes. Hiring aSeattle DUI lawyer to help can – at a minimum –
reduce those penalties, and can help direct people on how to best deal
with their DUI charge. So it should go without saying that someone cited
for DUI should hire a qualified Seattle DUI lawyer
as soon as possible. Driving Under the Influence charges can cause
havoc on a person’s personal and professional life. Anyone charged with
DUI in Washington State should immediately seek the assistance of a
seasoned Seattle DUI lawyer.