Fatal car crashes involving marijuana use have tripled in the U.S. in the last decade, according to a new study revealing the dark side of marijuana legalization.
"Currently, one of nine drivers involved in fatal crashes would test positive for marijuana," said study co-author Dr. Guohua Li, director of the Center for Injury Epidemiology and Prevention at Columbia. "If this trend continues, in five or six years non-alcohol drugs will overtake alcohol to become the most common substance involved in deaths related to impaired driving."
Researchers from Columbia University's Mailman School of Public Health viewed crash statistics from six states, including California, Hawaii, Illinois, New Hampshire, Rhode Island and West Virginia. These states routinely gather toxicology tests from drivers involved in fatal car crashes.
Li said alcohol contributed to the same percentage of traffic deaths over a decade, but the influence of drugs played an ever-increasing role.
While drugs played a part in 4 percent of traffic deaths in 1999, it was the main drug involved in 12 percent of traffic deaths in 2010.
The increase in marijuana use occurred across bother genders and all ages.
Research showed the combination of drugs alcohol and marijuana compounds the risk of fatalities.
"If a driver is under the influence of alcohol, their risk of a fatal crash is 13 times higher than the risk of the driver who is not under the influence of alcohol," Li said. "But if the driver is under the influence of both alcohol and marijuana, their risk increases to 24 times that of a sober person."
“It’s a wake-up call for us in highway safety,” said Jonathan Adkins, deputy executive director of the Governors Highway Safety Association. “The legalization of pot is going to spread to other states. It’s not even a partisan issue at this point. Our expectation is this will become the norm rather than the rarity.”
Li said authorities don’t currently have a viable test to check for marijuana intoxication.
“In the case of marijuana, I would say in maybe five years or more you will see some testing method or technique that may not as accurate as the Breathalyzer, but is more accurate than the testing devices we have today,” Li said.