Study links legalized pot with increase in car crash claims

Henrietta Brewer
June 26, 2017

The first study released found a link between legalized recreational marijuana and an increase in auto crashes.

The Highway Loss Data Institute, a leading insurance research group, released the results Thursday saying the study found collision claims in Colorado, Washington, and OR went up 2.7 per cent in the years since legal pot sales began when compared with surrounding states.

Their study shows collisions reported to insurance companies in Colorado, Oregon and Washington were a combined three percent higher than what would have been expected if those states hadn't legalized cannabis.

Matt Moore, senior vice president of the non-profit company behind the study, says the research is necessary, as states must have all the facts before deciding to open the marijuana floodgates.

"Worry that legalized marijuana is increasing crash rates isn't misplaced", David Zuby, executive vice president and chief research officer for the Insurance Institute for Highway Safety, said in a statement. "There is a range of results that indicate there's a need for additional work here".


The authors of that study analyzed federal data on fatal vehicle crashes from 2009 to 2015. The researchers characterized that number as small, but significant.

Dr. Jayson D. Aydelotte, the lead author on the report, could not be immediately reached for comment Friday or to provide the full report, including supplemental appendices showing additional analysis.

Another study released a year ago by AAA's safety foundation stated that legal THC limits established by states with legal marijuana have no scientific basis, and could result in innocent drivers being convicted while guilty drivers are released.

But marijuana advocates should make no excuses for the effect that legalization has had on highway safety in the state, even if it is not the effect that alcohol has.

"I don't want to minimize the issue - I think it's an important issue that needs to be studied", he said. That study was based on an examination of 2.5 million insurance claims from January 2012 to October 2016. That also reduced the racial disparities in the stops, according to a new analysis of police data, but not by much.


Marijuana legalization is causing concerns across the US over high driving and how to accurately test drivers for the substance.

Vehicle accidents are on the rise in legal states, and some data crunchers are pointing their fingers at recreational marijuana.

Additionally, while drivers may have THC in their system, it's less certain to know what extent they're impaired, he said.

According to a 2016 factcheck.org report, "from 2006 to 2014 overall, marijuana-related traffic deaths increased by 154 percent, from 37 fatalities with drivers testing positive for marijuana in 2006 to 94 in 2014 - hardly an insignificant increase". In Colorado, the change occurred gradually, with searches dropping initially by 30 percent, and then flatting out to a more than 50-percent drop within a year.

The findings showed that "Colorado saw the biggest estimated increase in claim frequency compared with its control states". These insurance companies have found several possible factors that could be responsible for the spike in vehicle crash claims.


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