According to a recent study by researchers from Columbia University, drivers who died in car accidents tested positive for marijuana three times more often from 1999 to 2010, when 20 states legalized marijuana for medical purposes.

According to a recent study by researchers from Columbia University, drivers who died in car accidents tested positive for marijuana three times more often from 1999 to 2010, when 20 states legalized marijuana for medical purposes.

The study looked at data from the Fatality Analysis Reported System covering 23 thousand drivers that died over the 11 year period of the study.

In 2010, 12 point 2 percent of the dead drivers tested positive for cannabinol, compared to the 4 point 2 percent that tested positive in 1999.

The substance most commonly found in the dead drivers’ bodies was alcohol, with 40 percent of the subjects testing positive.

Doctor Guohua Li, co-author of the study from the Columbia University Medical Center (1,5,2) said: “If the current trends continue, non-alcohol drugs, such as marijuana, will overtake alcohol in traffic fatalities around 2020.”

Another study based on the same data showed that in states with legalized medical marijuana, fatal car accidents actually decreased by up to 11 percent in the first year of legalization.

Also there was reportedly a 13 percent decrease in the number of drunk driving related deaths in places that have legalized medical marijuana.