studies on the effects of marijuana on drivers in states where it
is allowed for recreational use came to different conclusions
about whether it increases risks behind the wheel.
A study by the American Journal of Public Health published on
Thursday looked at motor vehicle fatalities and found no
significant increase in Colorado and Washington State, where
recreational marijuana use is legal, compared with eight states
where it is not legal that have similar populations, vehicle
ownership, and traffic laws. Alabama, Kentucky and Texas were
among the states in the comparison group.
“Our study focused on deaths and actually found what we expected
going into this,” Jason Adedoyte, lead author of the study said
in a telephone interview. Adedoyte is a trauma surgeon at Dell
Seton Medical Center at the University of Texas at Austin.
“Back in 2012 some argued that people would ride around in their
cars crash and die. Our study proved that isn’t true,” he said.
The American Journal of Public Health examined data from 2009 to
2015 taken from the U.S. Fatality Analysis Reporting System.
In another study published on Wednesday, the Highway Loss Data
Institute analyzed the frequency of car insurance collision
claims in Washington, Colorado and Oregon, where recreational
marijuana is also permitted.
It found a 3 percent increase in collision claims in those states
compared with Wyoming, Idaho and Nevada, where it is not legal.
“In states that passed legislation approving the recreational use
of marijuana, the data showed that there was a strong indicator
that marijuana was a factor in considering the rise of claims,”
Matt Moore, senior vice president of The Highway Loss Data
Institute, said in a telephone interview.
The Institute examined about 2.5 million insurance collision
claims from January 2012 and October 2016.
Mason Tvert, communication director of the Washington, D.C.-based
Marijuana Policy Project, a pro-legalization group, questioned
the methodology of the Institute’s study.
“There’s no clear evidence that marijuana is a factor. It’s going
to take several years and studies before we can determine that,”
he said in a telephone interview.
The Institute’s Moore defended its approach, saying, “We looked
at the correlation of states with similar insurance claim
frequencies, and the states we chose had the highest
Federal law prohibits recreational use of marijuana in the
country, however, it has been approved by eight states including
Maine, Massachusetts, Colorado, Washington, Alaska, Oregon,
California, Nevada and the District of Columbia.
(Reporting by Taylor T. Harris in New York; Editing by Frank