Some studies have found that using the drug could more than double crash risk, while others, including a large-scale federal case-control study, have failed to find a link between marijuana use and crashes.
A recent study done by the Highway Loss Institute shows a 3 percent increase in crashes in Oregon, Colorado and Washington, where recreational marijuana is legal.
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. Collision claims have increased as a result, according to a auto insurance-related non-profit.
Authors also reported no association between adult use marijuana legalization and the total number of non-fatal crashes.
The American Journal of Public Health study "Crash Fatality Rates After Recreational Marijuana Legalization in Washington and Colorado", by Jayson D. Aydelotte (MD), Lawrence H. Brown (PhD), Kevin M. Luftman (MD), Alexandra L. Mardock (BA), Pedro G.R. Teixeira (MD), Ben Coopwood (MD) and Carlos V.R. Brown (MD), is much more straightforward.
Meanwhile, the HLDI is planning to conduct more of these studies and has started a large-scale case-control research in OR to determine whether legalized marijuana use is causing automotive injuries.
According to the study, more drivers admit to using marijuana before getting behind the wheel and it's showing up more frequently amongst people involved in crashes.
"We'll continue to monitor these states and add additional states to the analysis". The research examined crash data in three of the first states to make pot legal. In Oregon, that number is 4.5 percent, and in Colorado there's been a 14 percent increase. Legal recreational pot sales in Colorado began in January 2014, followed six months later in Washington, and in October 2015 in Oregon. "We see strong evidence of an increased crash risk in states that have approved recreational marijuana sales".
The findings showed that "Colorado saw the biggest estimated increase in claim frequency compared with its control states". The republican says he will appoint a commission to study a legalized system. "It is something states need to look at when they're considering legalization".
They then compared this data to neighboring states.
Armentano is the deputy director of NORML (the National Organization for the Reform of Marijuana Laws) and an adviser for Freedom Leaf. The findings "should give other states eyeing legalization pause", said David Zuby, IIHS executive vice president and chief research officer, in a statement.